Граф коммитов

8538 Коммитов

Автор SHA1 Сообщение Дата
Johannes Holland 6422cbd3c5 tpm: Remove read16/read32/write32 calls from tpm_tis_phy_ops
Only tpm_tis and tpm_tis_synquacer have a dedicated way to access
multiple bytes at once, every other driver will just fall back to
read_bytes/write_bytes. Therefore, remove the read16/read32/write32
calls and move their logic to read_bytes/write_bytes.

Suggested-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Johannes Holland <johannes.holland@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-05-23 18:47:49 +03:00
Xiu Jianfeng d0dc1a7100 tpm: ibmvtpm: Correct the return value in tpm_ibmvtpm_probe()
Currently it returns zero when CRQ response timed out, it should return
an error code instead.

Fixes: d8d74ea3c0 ("tpm: ibmvtpm: Wait for buffer to be set before proceeding")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-05-23 18:47:49 +03:00
Haowen Bai 80b8a39777 tpm/tpm_ftpm_tee: Return true/false (not 1/0) from bool functions
Return boolean values ("true" or "false") instead of 1 or 0 from bool
functions.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-05-23 18:47:49 +03:00
Jason A. Donenfeld 1ce6c8d68f random: check for signals after page of pool writes
get_random_bytes_user() checks for signals after producing a PAGE_SIZE
worth of output, just like /dev/zero does. write_pool() is doing
basically the same work (actually, slightly more expensive), and so
should stop to check for signals in the same way. Let's also name it
write_pool_user() to match get_random_bytes_user(), so this won't be
misused in the future.

Before this patch, massive writes to /dev/urandom would tie up the
process for an extremely long time and make it unterminatable. After, it
can be successfully interrupted. The following test program can be used
to see this works as intended:

  #include <unistd.h>
  #include <fcntl.h>
  #include <signal.h>
  #include <stdio.h>

  static unsigned char x[~0U];

  static void handle(int) { }

  int main(int argc, char *argv[])
  {
    pid_t pid = getpid(), child;
    int fd;
    signal(SIGUSR1, handle);
    if (!(child = fork())) {
      for (;;)
        kill(pid, SIGUSR1);
    }
    fd = open("/dev/urandom", O_WRONLY);
    pause();
    printf("interrupted after writing %zd bytes\n", write(fd, x, sizeof(x)));
    close(fd);
    kill(child, SIGTERM);
    return 0;
  }

Result before: "interrupted after writing 2147479552 bytes"
Result after: "interrupted after writing 4096 bytes"

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-22 22:34:31 +02:00
Jens Axboe 79025e727a random: wire up fops->splice_{read,write}_iter()
Now that random/urandom is using {read,write}_iter, we can wire it up to
using the generic splice handlers.

Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[Jason: added the splice_write path. Note that sendfile() and such still
 does not work for read, though it does for write, because of a file
 type restriction in splice_direct_to_actor(), which I'll address
 separately.]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-20 18:26:48 +02:00
Jens Axboe 22b0a222af random: convert to using fops->write_iter()
Now that the read side has been converted to fix a regression with
splice, convert the write side as well to have some symmetry in the
interface used (and help deprecate ->write()).

Signed-off-by: Jens Axboe <axboe@kernel.dk>
[Jason: cleaned up random_ioctl a bit, require full writes in
 RNDADDENTROPY since it's crediting entropy, simplify control flow of
 write_pool(), and incorporate suggestions from Al.]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-20 18:26:48 +02:00
Jens Axboe 1b388e7765 random: convert to using fops->read_iter()
This is a pre-requisite to wiring up splice() again for the random
and urandom drivers. It also allows us to remove the INT_MAX check in
getrandom(), because import_single_range() applies capping internally.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
[Jason: rewrote get_random_bytes_user() to simplify and also incorporate
 additional suggestions from Al.]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-20 18:26:48 +02:00
Yang Yingliang e4e62bbc6a hwrng: omap3-rom - fix using wrong clk_disable() in omap_rom_rng_runtime_resume()
'ddata->clk' is enabled by clk_prepare_enable(), it should be disabled
by clk_disable_unprepare().

Fixes: 8d9d4bdc49 ("hwrng: omap3-rom - Use runtime PM instead of custom functions")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-05-20 13:54:45 +08:00
Ilpo Järvinen ef44c6c1e8 pcmcia: synclink_cs: Don't allow CS5-6
Only CS7 and CS8 seem supported but CSIZE was not sanitized in termios
c_cflag. The driver sets 7 bits whenever data_bits is not 8 so default
to CS7 when CSIZE is not CS8.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220519081808.3776-10-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-19 18:32:40 +02:00
Ilpo Järvinen 9fafe73351 tty: remove CMSPAR ifdefs
CMSPAR is defined by all architectures since commit 6bf08cb246
("[PATCH] Add CMSPAR to termbits.h for powerpc and alpha").

Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220513082906.11096-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-19 18:26:16 +02:00
Jason A. Donenfeld 3092adcef3 random: unify batched entropy implementations
There are currently two separate batched entropy implementations, for
u32 and u64, with nearly identical code, with the goal of avoiding
unaligned memory accesses and letting the buffers be used more
efficiently. Having to maintain these two functions independently is a
bit of a hassle though, considering that they always need to be kept in
sync.

This commit factors them out into a type-generic macro, so that the
expansion produces the same code as before, such that diffing the
assembly shows no differences. This will also make it easier in the
future to add u16 and u8 batches.

This was initially tested using an always_inline function and letting
gcc constant fold the type size in, but the code gen was less efficient,
and in general it was more verbose and harder to follow. So this patch
goes with the boring macro solution, similar to what's already done for
the _wait functions in random.h.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:15 +02:00
Jason A. Donenfeld 5ad7dd882e random: move randomize_page() into mm where it belongs
randomize_page is an mm function. It is documented like one. It contains
the history of one. It has the naming convention of one. It looks
just like another very similar function in mm, randomize_stack_top().
And it has always been maintained and updated by mm people. There is no
need for it to be in random.c. In the "which shape does not look like
the other ones" test, pointing to randomize_page() is correct.

So move randomize_page() into mm/util.c, right next to the similar
randomize_stack_top() function.

This commit contains no actual code changes.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:15 +02:00
Jason A. Donenfeld 6701de6c51 random: remove mostly unused async readiness notifier
The register_random_ready_notifier() notifier is somewhat complicated,
and was already recently rewritten to use notifier blocks. It is only
used now by one consumer in the kernel, vsprintf.c, for which the async
mechanism is really overly complex for what it actually needs. This
commit removes register_random_ready_notifier() and unregister_random_
ready_notifier(), because it just adds complication with little utility,
and changes vsprintf.c to just check on `!rng_is_initialized() &&
!rng_has_arch_random()`, which will eventually be true. Performance-
wise, that code was already using a static branch, so there's basically
no overhead at all to this change.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Petr Mladek <pmladek@suse.com> # for vsprintf.c
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:15 +02:00
Jason A. Donenfeld 248561ad25 random: remove get_random_bytes_arch() and add rng_has_arch_random()
The RNG incorporates RDRAND into its state at boot and every time it
reseeds, so there's no reason for callers to use it directly. The
hashing that the RNG does on it is preferable to using the bytes raw.

The only current use case of get_random_bytes_arch() is vsprintf's
siphash key for pointer hashing, which uses it to initialize the pointer
secret earlier than usual if RDRAND is available. In order to replace
this narrow use case, just expose whether RDRAND is mixed into the RNG,
with a new function called rng_has_arch_random(). With that taken care
of, there are no users of get_random_bytes_arch() left, so it can be
removed.

Later, if trust_cpu gets turned on by default (as most distros are
doing), this one use of rng_has_arch_random() can probably go away as
well.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Petr Mladek <pmladek@suse.com> # for vsprintf.c
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:15 +02:00
Jason A. Donenfeld 560181c27b random: move initialization functions out of hot pages
Much of random.c is devoted to initializing the rng and accounting for
when a sufficient amount of entropy has been added. In a perfect world,
this would all happen during init, and so we could mark these functions
as __init. But in reality, this isn't the case: sometimes the rng only
finishes initializing some seconds after system init is finished.

For this reason, at the moment, a whole host of functions that are only
used relatively close to system init and then never again are intermixed
with functions that are used in hot code all the time. This creates more
cache misses than necessary.

In order to pack the hot code closer together, this commit moves the
initialization functions that can't be marked as __init into
.text.unlikely by way of the __cold attribute.

Of particular note is moving credit_init_bits() into a macro wrapper
that inlines the crng_ready() static branch check. This avoids a
function call to a nop+ret, and most notably prevents extra entropy
arithmetic from being computed in mix_interrupt_randomness().

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:15 +02:00
Jason A. Donenfeld a19402634c random: make consistent use of buf and len
The current code was a mix of "nbytes", "count", "size", "buffer", "in",
and so forth. Instead, let's clean this up by naming input parameters
"buf" (or "ubuf") and "len", so that you always understand that you're
reading this variety of function argument.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:15 +02:00
Jason A. Donenfeld f5bda35fba random: use static branch for crng_ready()
Since crng_ready() is only false briefly during initialization and then
forever after becomes true, we don't need to evaluate it after, making
it a prime candidate for a static branch.

One complication, however, is that it changes state in a particular call
to credit_init_bits(), which might be made from atomic context, which
means we must kick off a workqueue to change the static key. Further
complicating things, credit_init_bits() may be called sufficiently early
on in system initialization such that system_wq is NULL.

Fortunately, there exists the nice function execute_in_process_context(),
which will immediately execute the function if !in_interrupt(), and
otherwise defer it to a workqueue. During early init, before workqueues
are available, in_interrupt() is always false, because interrupts
haven't even been enabled yet, which means the function in that case
executes immediately. Later on, after workqueues are available,
in_interrupt() might be true, but in that case, the work is queued in
system_wq and all goes well.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-19 16:54:10 +02:00
Juergen Gross 5e0afd8eab xen/tpmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
Simplify tpmfront's ring creation and removal via xenbus_setup_ring()
and xenbus_teardown_ring(), which are provided exactly for the use
pattern as seen in this driver.

Signed-off-by: Juergen Gross <jgross@suse.com>
2022-05-19 14:21:59 +02:00
Jason A. Donenfeld 12e45a2a63 random: credit architectural init the exact amount
RDRAND and RDSEED can fail sometimes, which is fine. We currently
initialize the RNG with 512 bits of RDRAND/RDSEED. We only need 256 bits
of those to succeed in order to initialize the RNG. Instead of the
current "all or nothing" approach, actually credit these contributions
the amount that is actually contributed.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:53 +02:00
Jason A. Donenfeld 2f14062bb1 random: handle latent entropy and command line from random_init()
Currently, start_kernel() adds latent entropy and the command line to
the entropy bool *after* the RNG has been initialized, deferring when
it's actually used by things like stack canaries until the next time
the pool is seeded. This surely is not intended.

Rather than splitting up which entropy gets added where and when between
start_kernel() and random_init(), just do everything in random_init(),
which should eliminate these kinds of bugs in the future.

While we're at it, rename the awkwardly titled "rand_initialize()" to
the more standard "random_init()" nomenclature.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:53 +02:00
Jason A. Donenfeld 8a5b8a4a4c random: use proper jiffies comparison macro
This expands to exactly the same code that it replaces, but makes things
consistent by using the same macro for jiffy comparisons throughout.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:53 +02:00
Jason A. Donenfeld cc1e127bfa random: remove ratelimiting for in-kernel unseeded randomness
The CONFIG_WARN_ALL_UNSEEDED_RANDOM debug option controls whether the
kernel warns about all unseeded randomness or just the first instance.
There's some complicated rate limiting and comparison to the previous
caller, such that even with CONFIG_WARN_ALL_UNSEEDED_RANDOM enabled,
developers still don't see all the messages or even an accurate count of
how many were missed. This is the result of basically parallel
mechanisms aimed at accomplishing more or less the same thing, added at
different points in random.c history, which sort of compete with the
first-instance-only limiting we have now.

It turns out, however, that nobody cares about the first unseeded
randomness instance of in-kernel users. The same first user has been
there for ages now, and nobody is doing anything about it. It isn't even
clear that anybody _can_ do anything about it. Most places that can do
something about it have switched over to using get_random_bytes_wait()
or wait_for_random_bytes(), which is the right thing to do, but there is
still much code that needs randomness sometimes during init, and as a
geeneral rule, if you're not using one of the _wait functions or the
readiness notifier callback, you're bound to be doing it wrong just
based on that fact alone.

So warning about this same first user that can't easily change is simply
not an effective mechanism for anything at all. Users can't do anything
about it, as the Kconfig text points out -- the problem isn't in
userspace code -- and kernel developers don't or more often can't react
to it.

Instead, show the warning for all instances when CONFIG_WARN_ALL_UNSEEDED_RANDOM
is set, so that developers can debug things need be, or if it isn't set,
don't show a warning at all.

At the same time, CONFIG_WARN_ALL_UNSEEDED_RANDOM now implies setting
random.ratelimit_disable=1 on by default, since if you care about one
you probably care about the other too. And we can clean up usage around
the related urandom_warning ratelimiter as well (whose behavior isn't
changing), so that it properly counts missed messages after the 10
message threshold is reached.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:53 +02:00
Jason A. Donenfeld 68c9c8b192 random: move initialization out of reseeding hot path
Initialization happens once -- by way of credit_init_bits() -- and then
it never happens again. Therefore, it doesn't need to be in
crng_reseed(), which is a hot path that is called multiple times. It
also doesn't make sense to have there, as initialization activity is
better associated with initialization routines.

After the prior commit, crng_reseed() now won't be called by multiple
concurrent callers, which means that we can safely move the
"finialize_init" logic into crng_init_bits() unconditionally.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:53 +02:00
Jason A. Donenfeld fed7ef0616 random: avoid initializing twice in credit race
Since all changes of crng_init now go through credit_init_bits(), we can
fix a long standing race in which two concurrent callers of
credit_init_bits() have the new bit count >= some threshold, but are
doing so with crng_init as a lower threshold, checked outside of a lock,
resulting in crng_reseed() or similar being called twice.

In order to fix this, we can use the original cmpxchg value of the bit
count, and only change crng_init when the bit count transitions from
below a threshold to meeting the threshold.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:53 +02:00
Jason A. Donenfeld e3d2c5e79a random: use symbolic constants for crng_init states
crng_init represents a state machine, with three states, and various
rules for transitions. For the longest time, we've been managing these
with "0", "1", and "2", and expecting people to figure it out. To make
the code more obvious, replace these with proper enum values
representing the transition, and then redocument what each of these
states mean.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:52 +02:00
Jason A. Donenfeld e73aaae2fa siphash: use one source of truth for siphash permutations
The SipHash family of permutations is currently used in three places:

- siphash.c itself, used in the ordinary way it was intended.
- random32.c, in a construction from an anonymous contributor.
- random.c, as part of its fast_mix function.

Each one of these places reinvents the wheel with the same C code, same
rotation constants, and same symmetry-breaking constants.

This commit tidies things up a bit by placing macros for the
permutations and constants into siphash.h, where each of the three .c
users can access them. It also leaves a note dissuading more users of
them from emerging.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:52 +02:00
Jason A. Donenfeld 791332b3cb random: help compiler out with fast_mix() by using simpler arguments
Now that fast_mix() has more than one caller, gcc no longer inlines it.
That's fine. But it also doesn't handle the compound literal argument we
pass it very efficiently, nor does it handle the loop as well as it
could. So just expand the code to spell out this function so that it
generates the same code as it did before. Performance-wise, this now
behaves as it did before the last commit. The difference in actual code
size on x86 is 45 bytes, which is less than a cache line.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:52 +02:00
Jason A. Donenfeld e3e33fc2ea random: do not use input pool from hard IRQs
Years ago, a separate fast pool was added for interrupts, so that the
cost associated with taking the input pool spinlocks and mixing into it
would be avoided in places where latency is critical. However, one
oversight was that add_input_randomness() and add_disk_randomness()
still sometimes are called directly from the interrupt handler, rather
than being deferred to a thread. This means that some unlucky interrupts
will be caught doing a blake2s_compress() call and potentially spinning
on input_pool.lock, which can also be taken by unprivileged users by
writing into /dev/urandom.

In order to fix this, add_timer_randomness() now checks whether it is
being called from a hard IRQ and if so, just mixes into the per-cpu IRQ
fast pool using fast_mix(), which is much faster and can be done
lock-free. A nice consequence of this, as well, is that it means hard
IRQ context FPU support is likely no longer useful.

The entropy estimation algorithm used by add_timer_randomness() is also
somewhat different than the one used for add_interrupt_randomness(). The
former looks at deltas of deltas of deltas, while the latter just waits
for 64 interrupts for one bit or for one second since the last bit. In
order to bridge these, and since add_interrupt_randomness() runs after
an add_timer_randomness() that's called from hard IRQ, we add to the
fast pool credit the related amount, and then subtract one to account
for add_interrupt_randomness()'s contribution.

A downside of this, however, is that the num argument is potentially
attacker controlled, which puts a bit more pressure on the fast_mix()
sponge to do more than it's really intended to do. As a mitigating
factor, the first 96 bits of input aren't attacker controlled (a cycle
counter followed by zeros), which means it's essentially two rounds of
siphash rather than one, which is somewhat better. It's also not that
much different from add_interrupt_randomness()'s use of the irq stack
instruction pointer register.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Filipe Manana <fdmanana@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:52 +02:00
Greg Kroah-Hartman d6da35e0c6 Merge 5.18-rc7 into usb-next
We need the tty fixes in here as well, as we need to revert one of them :(

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-16 15:39:23 +02:00
Jason A. Donenfeld a4b5c26b79 random: order timer entropy functions below interrupt functions
There are no code changes here; this is just a reordering of functions,
so that in subsequent commits, the timer entropy functions can call into
the interrupt ones.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-16 01:27:24 +02:00
Jason A. Donenfeld e85c0fc1d9 random: do not pretend to handle premature next security model
Per the thread linked below, "premature next" is not considered to be a
realistic threat model, and leads to more serious security problems.

"Premature next" is the scenario in which:

- Attacker compromises the current state of a fully initialized RNG via
  some kind of infoleak.
- New bits of entropy are added directly to the key used to generate the
  /dev/urandom stream, without any buffering or pooling.
- Attacker then, somehow having read access to /dev/urandom, samples RNG
  output and brute forces the individual new bits that were added.
- Result: the RNG never "recovers" from the initial compromise, a
  so-called violation of what academics term "post-compromise security".

The usual solutions to this involve some form of delaying when entropy
gets mixed into the crng. With Fortuna, this involves multiple input
buckets. With what the Linux RNG was trying to do prior, this involves
entropy estimation.

However, by delaying when entropy gets mixed in, it also means that RNG
compromises are extremely dangerous during the window of time before
the RNG has gathered enough entropy, during which time nonces may become
predictable (or repeated), ephemeral keys may not be secret, and so
forth. Moreover, it's unclear how realistic "premature next" is from an
attack perspective, if these attacks even make sense in practice.

Put together -- and discussed in more detail in the thread below --
these constitute grounds for just doing away with the current code that
pretends to handle premature next. I say "pretends" because it wasn't
doing an especially great job at it either; should we change our mind
about this direction, we would probably implement Fortuna to "fix" the
"problem", in which case, removing the pretend solution still makes
sense.

This also reduces the crng reseed period from 5 minutes down to 1
minute. The rationale from the thread might lead us toward reducing that
even further in the future (or even eliminating it), but that remains a
topic of a future commit.

At a high level, this patch changes semantics from:

    Before: Seed for the first time after 256 "bits" of estimated
    entropy have been accumulated since the system booted. Thereafter,
    reseed once every five minutes, but only if 256 new "bits" have been
    accumulated since the last reseeding.

    After: Seed for the first time after 256 "bits" of estimated entropy
    have been accumulated since the system booted. Thereafter, reseed
    once every minute.

Most of this patch is renaming and removing: POOL_MIN_BITS becomes
POOL_INIT_BITS, credit_entropy_bits() becomes credit_init_bits(),
crng_reseed() loses its "force" parameter since it's now always true,
the drain_entropy() function no longer has any use so it's removed,
entropy estimation is skipped if we've already init'd, the various
notifiers for "low on entropy" are now only active prior to init, and
finally, some documentation comments are cleaned up here and there.

Link: https://lore.kernel.org/lkml/YmlMGx6+uigkGiZ0@zx2c4.com/
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Nadia Heninger <nadiah@cs.ucsd.edu>
Cc: Tom Ristenpart <ristenpart@cornell.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-15 12:11:58 +02:00
Jason A. Donenfeld 5c3b747ef5 random: use first 128 bits of input as fast init
Before, the first 64 bytes of input, regardless of how entropic it was,
would be used to mutate the crng base key directly, and none of those
bytes would be credited as having entropy. Then 256 bits of credited
input would be accumulated, and only then would the rng transition from
the earlier "fast init" phase into being actually initialized.

The thinking was that by mixing and matching fast init and real init, an
attacker who compromised the fast init state, considered easy to do
given how little entropy might be in those first 64 bytes, would then be
able to bruteforce bits from the actual initialization. By keeping these
separate, bruteforcing became impossible.

However, by not crediting potentially creditable bits from those first 64
bytes of input, we delay initialization, and actually make the problem
worse, because it means the user is drawing worse random numbers for a
longer period of time.

Instead, we can take the first 128 bits as fast init, and allow them to
be credited, and then hold off on the next 128 bits until they've
accumulated. This is still a wide enough margin to prevent bruteforcing
the rng state, while still initializing much faster.

Then, rather than trying to piecemeal inject into the base crng key at
various points, instead just extract from the pool when we need it, for
the crng_init==0 phase. Performance may even be better for the various
inputs here, since there are likely more calls to mix_pool_bytes() then
there are to get_random_bytes() during this phase of system execution.

Since the preinit injection code is gone, bootloader randomness can then
do something significantly more straight forward, removing the weird
system_wq hack in hwgenerator randomness.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-13 23:59:23 +02:00
Jason A. Donenfeld cbe89e5a37 random: do not use batches when !crng_ready()
It's too hard to keep the batches synchronized, and pointless anyway,
since in !crng_ready(), we're updating the base_crng key really often,
where batching only hurts. So instead, if the crng isn't ready, just
call into get_random_bytes(). At this stage nothing is performance
critical anyhow.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-13 23:59:23 +02:00
Jason A. Donenfeld b7b67d1391 random: mix in timestamps and reseed on system restore
Since the RNG loses freshness with system suspend/hibernation, when we
resume, immediately reseed using whatever data we can, which for this
particular case is the various timestamps regarding system suspend time,
in addition to more generally the RDSEED/RDRAND/RDTSC values that happen
whenever the crng reseeds.

On systems that suspend and resume automatically all the time -- such as
Android -- we skip the reseeding on suspend resumption, since that could
wind up being far too busy. This is the same trade-off made in
WireGuard.

In addition to reseeding upon resumption always mix into the pool these
various stamps on every power notification event.

Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-13 23:59:23 +02:00
Jason A. Donenfeld 78c768e619 random: vary jitter iterations based on cycle counter speed
Currently, we do the jitter dance if two consecutive reads to the cycle
counter return different values. If they do, then we consider the cycle
counter to be fast enough that one trip through the scheduler will yield
one "bit" of credited entropy. If those two reads return the same value,
then we assume the cycle counter is too slow to show meaningful
differences.

This methodology is flawed for a variety of reasons, one of which Eric
posted a patch to fix in [1]. The issue that patch solves is that on a
system with a slow counter, you might be [un]lucky and read the counter
_just_ before it changes, so that the second cycle counter you read
differs from the first, even though there's usually quite a large period
of time in between the two. For example:

| real time | cycle counter |
| --------- | ------------- |
| 3         | 5             |
| 4         | 5             |
| 5         | 5             |
| 6         | 5             |
| 7         | 5             | <--- a
| 8         | 6             | <--- b
| 9         | 6             | <--- c

If we read the counter at (a) and compare it to (b), we might be fooled
into thinking that it's a fast counter, when in reality it is not. The
solution in [1] is to also compare counter (b) to counter (c), on the
theory that if the counter is _actually_ slow, and (a)!=(b), then
certainly (b)==(c).

This helps solve this particular issue, in one sense, but in another
sense, it mostly functions to disallow jitter entropy on these systems,
rather than simply taking more samples in that case.

Instead, this patch takes a different approach. Right now we assume that
a difference in one set of consecutive samples means one "bit" of
credited entropy per scheduler trip. We can extend this so that a
difference in two sets of consecutive samples means one "bit" of
credited entropy per /two/ scheduler trips, and three for three, and
four for four. In other words, we can increase the amount of jitter
"work" we require for each "bit", depending on how slow the cycle
counter is.

So this patch takes whole bunch of samples, sees how many of them are
different, and divides to find the amount of work required per "bit",
and also requires that at least some minimum of them are different in
order to attempt any jitter entropy.

Note that this approach is still far from perfect. It's not a real
statistical estimate on how much these samples vary; it's not a
real-time analysis of the relevant input data. That remains a project
for another time. However, it makes the same (partly flawed) assumptions
as the code that's there now, so it's probably not worse than the status
quo, and it handles the issue Eric mentioned in [1]. But, again, it's
probably a far cry from whatever a really robust version of this would
be.

[1] https://lore.kernel.org/lkml/20220421233152.58522-1-ebiggers@kernel.org/
    https://lore.kernel.org/lkml/20220421192939.250680-1-ebiggers@kernel.org/

Cc: Eric Biggers <ebiggers@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-13 23:59:23 +02:00
Jason A. Donenfeld 4b758eda85 random: insist on random_get_entropy() existing in order to simplify
All platforms are now guaranteed to provide some value for
random_get_entropy(). In case some bug leads to this not being so, we
print a warning, because that indicates that something is really very
wrong (and likely other things are impacted too). This should never be
hit, but it's a good and cheap way of finding out if something ever is
problematic.

Since we now have viable fallback code for random_get_entropy() on all
platforms, which is, in the worst case, not worse than jiffies, we can
count on getting the best possible value out of it. That means there's
no longer a use for using jiffies as entropy input. It also means we no
longer have a reason for doing the round-robin register flow in the IRQ
handler, which was always of fairly dubious value.

Instead we can greatly simplify the IRQ handler inputs and also unify
the construction between 64-bits and 32-bits. We now collect the cycle
counter and the return address, since those are the two things that
matter. Because the return address and the irq number are likely
related, to the extent we mix in the irq number, we can just xor it into
the top unchanging bytes of the return address, rather than the bottom
changing bytes of the cycle counter as before. Then, we can do a fixed 2
rounds of SipHash/HSipHash. Finally, we use the same construction of
hashing only half of the [H]SipHash state on 32-bit and 64-bit. We're
not actually discarding any entropy, since that entropy is carried
through until the next time. And more importantly, it lets us do the
same sponge-like construction everywhere.

Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-13 23:59:23 +02:00
Miaoqian Lin a508e33956 ipmi:ipmb: Fix refcount leak in ipmi_ipmb_probe
of_parse_phandle() returns a node pointer with refcount
incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.

Fixes: 00d93611f0 ("ipmi:ipmb: Add the ability to have a separate slave and master device")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Message-Id: <20220512044445.3102-1-linmq006@gmail.com>
Cc: stable@vger.kernel.org # v5.17+
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:04 -05:00
Yu Zhe 5396ccbd79 ipmi: remove unnecessary type castings
remove unnecessary void* type castings.

Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Message-Id: <20220421150941.7659-1-yuzhe@nfschina.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:04 -05:00
Corey Minyard 1016daf218 ipmi: Make two logs unique
There were two identical logs in two different places, so you couldn't
tell which one was being logged.  Make them unique.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:04 -05:00
Corey Minyard be8503597c ipmi:si: Convert pr_debug() to dev_dbg()
A device is available, use it.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:04 -05:00
Corey Minyard b2c6941a5c ipmi: Convert pr_debug() to dev_dbg()
A device is available at all debug points, use the right interface.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:04 -05:00
Corey Minyard 2ebaf18a0b ipmi: Fix pr_fmt to avoid compilation issues
The was it was wouldn't work in some situations, simplify it.  What was
there was unnecessary complexity.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:04 -05:00
Corey Minyard f214549d71 ipmi: Add an intializer for ipmi_recv_msg struct
Don't hand-initialize the struct here, create a macro to initialize it
so new fields added don't get forgotten in places.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:03 -05:00
Corey Minyard 9824117dd9 ipmi: Add an intializer for ipmi_smi_msg struct
There was a "type" element added to this structure, but some static
values were missed.  The default value will be zero, which is correct,
but create an initializer for the type and initialize the type properly
in the initializer to avoid future issues.

Reported-by: Joe Wiese <jwiese@rackspace.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:03 -05:00
Corey Minyard 7602b957e2 ipmi:ssif: Check for NULL msg when handling events and messages
Even though it's not possible to get into the SSIF_GETTING_MESSAGES and
SSIF_GETTING_EVENTS states without a valid message in the msg field,
it's probably best to be defensive here and check and print a log, since
that means something else went wrong.

Also add a default clause to that switch statement to release the lock
and print a log, in case the state variable gets messed up somehow.

Reported-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:03 -05:00
Stephen Kitt 0924c5a0cb ipmi: use simple i2c probe function
The i2c probe functions here don't use the id information provided in
their second argument, so the single-parameter i2c probe function
("probe_new") can be used instead.

This avoids scanning the identifier tables during probes.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Message-Id: <20220324171159.544565-1-steve@sk2.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
2022-05-12 10:00:03 -05:00
Corey Minyard d5d91586be ipmi: Add a sysfs count of total outstanding messages for an interface
Go through each user and add its message count to a total and print the
total.

It would be nice to have a per-user file, but there's no user sysfs
entity at this point to hang it off of.  Probably not worth the effort.

Based on work by Chen Guanqiao <chen.chenchacha@foxmail.com>

Cc: Chen Guanqiao <chen.chenchacha@foxmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:03 -05:00
Corey Minyard f60231885f ipmi: Add a sysfs interface to view the number of users
A count of users is kept for each interface, allow it to be viewed.

Based on work by Chen Guanqiao <chen.chenchacha@foxmail.com>

Cc: Chen Guanqiao <chen.chenchacha@foxmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:03 -05:00
Corey Minyard 333730e456 ipmi: Limit the number of message a user may have outstanding
This way a rogue application can't use up a bunch of memory.

Based on work by Chen Guanqiao <chen.chenchacha@foxmail.com>

Cc: Chen Guanqiao <chen.chenchacha@foxmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:02 -05:00
Corey Minyard 8e76741c3d ipmi: Add a limit on the number of users that may use IPMI
Each user uses memory, we need limits to avoid a rogue program from
running the system out of memory.

Based on work by Chen Guanqiao <chen.chenchacha@foxmail.com>

Cc: Chen Guanqiao <chen.chenchacha@foxmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-05-12 10:00:02 -05:00
Herbert Xu 25dfae6840 hwrng: cn10k - Enable compile testing
This patch enables COMPILE_TEST for cn10k.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-05-06 18:16:55 +08:00
Linus Torvalds 3118d7ab3f Fix some issues that were reported
This has been in for-next for a bit (longer than the times would
 indicate, I had to rebase to add some text to the headers) and these are
 fixes that need to go in.
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Merge tag 'for-linus-5.17-2' of https://github.com/cminyard/linux-ipmi

Pull IPMI fixes from Corey Minyard:
 "Fix some issues that were reported.

  This has been in for-next for a bit (longer than the times would
  indicate, I had to rebase to add some text to the headers) and these
  are fixes that need to go in"

* tag 'for-linus-5.17-2' of https://github.com/cminyard/linux-ipmi:
  ipmi:ipmi_ipmb: Fix null-ptr-deref in ipmi_unregister_smi()
  ipmi: When handling send message responses, don't process the message
2022-05-04 11:01:31 -07:00
Greg Kroah-Hartman 9e6a907903 Merge 5.18-rc5 into tty-next
We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-02 14:56:14 +02:00
Greg Kroah-Hartman 35a7609639 Linux 5.18-rc5
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Merge 5.18-rc5 into char-misc-next

We need the char-misc fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-02 13:49:24 +02:00
Corey Minyard 9cc3aac425 ipmi:ipmi_ipmb: Fix null-ptr-deref in ipmi_unregister_smi()
KASAN report null-ptr-deref as follows:

KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:ipmi_unregister_smi+0x7d/0xd50 drivers/char/ipmi/ipmi_msghandler.c:3680
Call Trace:
 ipmi_ipmb_remove+0x138/0x1a0 drivers/char/ipmi/ipmi_ipmb.c:443
 ipmi_ipmb_probe+0x409/0xda1 drivers/char/ipmi/ipmi_ipmb.c:548
 i2c_device_probe+0x959/0xac0 drivers/i2c/i2c-core-base.c:563
 really_probe+0x3f3/0xa70 drivers/base/dd.c:541

In ipmi_ipmb_probe(), 'iidev->intf' is not set before
ipmi_register_smi() success.  And in the error handling case,
ipmi_ipmb_remove() is called to release resources, ipmi_unregister_smi()
is called without check 'iidev->intf', this will cause KASAN
null-ptr-deref issue.

General kernel style is to allow NULL to be passed into unregister
calls, so fix it that way.  This allows a NULL check to be removed in
other code.

Fixes: 57c9e3c9a3 ("ipmi:ipmi_ipmb: Unregister the SMI on remove")
Reported-by: Hulk Robot <hulkci@huawei.com>
Cc: stable@vger.kernel.org # v5.17+
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-04-29 10:06:52 -05:00
Corey Minyard 3d092ef093 ipmi: When handling send message responses, don't process the message
A chunk was dropped when the code handling send messages was rewritten.
Those messages shouldn't be processed normally, they are just an
indication that the message was successfully sent and the timers should
be started for the real response that should be coming later.

Add back in the missing chunk to just discard the message and go on.

Fixes: 059747c245 ("ipmi: Add support for IPMB direct messages")
Reported-by: Joe Wiese <jwiese@rackspace.com>
Cc: stable@vger.kernel.org # v5.16+
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Tested-by: Joe Wiese <jwiese@rackspace.com>
2022-04-29 10:06:37 -05:00
Colin Ian King 11aeb93089 hwrng: optee - remove redundant initialization to variable rng_size
Variable rng_size is being initialized with a value that is never read,
the variable is being re-assigned later on. The initialization is
redundant and can be removed.

Cleans up cppcheck warning:
Variable 'rng_size' is assigned a value that is never used.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-04-29 13:44:58 +08:00
Herbert Xu c6d3ffae0d Revert "hwrng: mpfs - Enable COMPILE_TEST"
This reverts commit 6a71277ce9.

The underlying option POLARFIRE_SOC_SYS_CTRL already supports
COMPILE_TEST so there is no need for this.  What's more, if
we force this option on without the underlying option it fails
to build.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-04-26 17:42:36 +08:00
Jason A. Donenfeld 8717627d6a random: document crng_fast_key_erasure() destination possibility
This reverts 35a33ff380 ("random: use memmove instead of memcpy for
remaining 32 bytes"), which was made on a totally bogus basis. The thing
it was worried about overlapping came from the stack, not from one of
its arguments, as Eric pointed out.

But the fact that this confusion even happened draws attention to the
fact that it's a bit non-obvious that the random_data parameter can
alias chacha_state, and in fact should do so when the caller can't rely
on the stack being cleared in a timely manner. So this commit documents
that.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-25 17:26:40 +02:00
Jason A. Donenfeld 830a4e5c48 /dev/mem: make reads and writes interruptible
In 8619e5bdee ("/dev/mem: Bail out upon SIGKILL."), /dev/mem became
killable, and that commit noted:

  Theoretically, reading/writing /dev/mem and /dev/kmem can become
  "interruptible". But this patch chose "killable". Future patch will
  make them "interruptible" so that we can revert to "killable" if
  some program regressed.

So now we take the next step in making it "interruptible", by changing
fatal_signal_pending() into signal_pending().

Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20220407122638.490660-1-Jason@zx2c4.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-24 17:31:01 +02:00
Hangyu Hua b67d19662f char: xillybus: fix a refcount leak in cleanup_dev()
usb_get_dev is called in xillyusb_probe. So it is better to call
usb_put_dev before xdev is released.

Acked-by: Eli Billauer <eli.billauer@gmail.com>
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20220406075703.23464-1-hbh25y@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-24 17:30:45 +02:00
Jakob Koschel 4834f9898c char: xillybus: replace usage of found with dedicated list iterator variable
To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Acked-by: Eli Billauer <eli.billauer@gmail.com>
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220324070939.59297-1-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-24 17:24:12 +02:00
Jakob Koschel 3a5e65023f char: misc: remove usage of list iterator past the loop body
In preparation to limit the scope of the list iterator to the list
traversal loop, use a dedicated pointer pointing to the found element [1].

Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220319201454.2511733-1-jakobkoschel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-24 17:15:12 +02:00
Vincent Whitchurch 7ea4aa70bf char: ttyprintk: register console
Register a console in the ttyprintk driver so that it can be selected
for /dev/console with console=ttyprintk on the kernel command line,
similar to other console drivers.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20220215141750.92808-1-vincent.whitchurch@axis.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-22 16:24:47 +02:00
Herbert Xu 6a71277ce9 hwrng: mpfs - Enable COMPILE_TEST
The dependency on HW_RANDOM is redundant so this patch removes it.
As this driver seems to cross-compile just fine we could also enable
COMPILE_TEST.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-04-21 17:53:55 +08:00
Vladis Dronov 32547a6aed hwrng: cn10k - Make check_rng_health() return an error code
Currently check_rng_health() returns zero unconditionally.
Make it to output an error code and return it.

Fixes: 38e9791a02 ("hwrng: cn10k - Add random number generator support")
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-04-21 17:53:55 +08:00
Vladis Dronov 753d677087 hwrng: cn10k - Optimize cn10k_rng_read()
This function assumes that sizeof(void) is 1 and arithmetic works for
void pointers. This is a GNU C extention and may not work with other
compilers. Change this by using an u8 pointer.

Also move cn10k_read_trng() out of a loop thus saving some cycles.

Fixes: 38e9791a02 ("hwrng: cn10k - Add random number generator support")
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-04-21 17:53:54 +08:00
Haowen Bai c50c29a806 tty: synclink_cs: Use bitwise instead of arithmetic operator for flags
This silences the following coccinelle warning:
drivers/s390/char/tape_34xx.c:360:38-39: WARNING: sum of probable bitmasks, consider |

we will try to make code cleaner

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Link: https://lore.kernel.org/r/1647846757-946-1-git-send-email-baihaowen@meizu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-20 19:42:40 +02:00
Jason A. Donenfeld 35a33ff380 random: use memmove instead of memcpy for remaining 32 bytes
In order to immediately overwrite the old key on the stack, before
servicing a userspace request for bytes, we use the remaining 32 bytes
of block 0 as the key. This means moving indices 8,9,a,b,c,d,e,f ->
4,5,6,7,8,9,a,b. Since 4 < 8, for the kernel implementations of
memcpy(), this doesn't actually appear to be a problem in practice. But
relying on that characteristic seems a bit brittle. So let's change that
to a proper memmove(), which is the by-the-books way of handling
overlapping memory copies.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-16 12:53:31 +02:00
Conor Dooley 716a757c83 hwrng: mpfs - add polarfire soc hwrng support
Add a driver to access the hardware random number generator on the
Polarfire SoC. The hwrng can only be accessed via the system controller,
so use the mailbox interface the system controller exposes to access the
hwrng.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-04-15 16:34:28 +08:00
Jason A. Donenfeld b0c3e796f2 random: make random_get_entropy() return an unsigned long
Some implementations were returning type `unsigned long`, while others
that fell back to get_cycles() were implicitly returning a `cycles_t` or
an untyped constant int literal. That makes for weird and confusing
code, and basically all code in the kernel already handled it like it
was an `unsigned long`. I recently tried to handle it as the largest
type it could be, a `cycles_t`, but doing so doesn't really help with
much.

Instead let's just make random_get_entropy() return an unsigned long all
the time. This also matches the commonly used `arch_get_random_long()`
function, so now RDRAND and RDTSC return the same sized integer, which
means one can fallback to the other more gracefully.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-13 13:58:57 +02:00
Jason A. Donenfeld 5209aed513 random: allow partial reads if later user copies fail
Rather than failing entirely if a copy_to_user() fails at some point,
instead we should return a partial read for the amount that succeeded
prior, unless none succeeded at all, in which case we return -EFAULT as
before.

This makes it consistent with other reader interfaces. For example, the
following snippet for /dev/zero outputs "4" followed by "1":

  int fd;
  void *x = mmap(NULL, 4096, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  assert(x != MAP_FAILED);
  fd = open("/dev/zero", O_RDONLY);
  assert(fd >= 0);
  printf("%zd\n", read(fd, x, 4));
  printf("%zd\n", read(fd, x + 4095, 4));
  close(fd);

This brings that same standard behavior to the various RNG reader
interfaces.

While we're at it, we can streamline the loop logic a little bit.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-13 13:58:57 +02:00
Jason A. Donenfeld e3c1c4fd9e random: check for signals every PAGE_SIZE chunk of /dev/[u]random
In 1448769c9c ("random: check for signal_pending() outside of
need_resched() check"), Jann pointed out that we previously were only
checking the TIF_NOTIFY_SIGNAL and TIF_SIGPENDING flags if the process
had TIF_NEED_RESCHED set, which meant in practice, super long reads to
/dev/[u]random would delay signal handling by a long time. I tried this
using the below program, and indeed I wasn't able to interrupt a
/dev/urandom read until after several megabytes had been read. The bug
he fixed has always been there, and so code that reads from /dev/urandom
without checking the return value of read() has mostly worked for a long
time, for most sizes, not just for <= 256.

Maybe it makes sense to keep that code working. The reason it was so
small prior, ignoring the fact that it didn't work anyway, was likely
because /dev/random used to block, and that could happen for pretty
large lengths of time while entropy was gathered. But now, it's just a
chacha20 call, which is extremely fast and is just operating on pure
data, without having to wait for some external event. In that sense,
/dev/[u]random is a lot more like /dev/zero.

Taking a page out of /dev/zero's read_zero() function, it always returns
at least one chunk, and then checks for signals after each chunk. Chunk
sizes there are of length PAGE_SIZE. Let's just copy the same thing for
/dev/[u]random, and check for signals and cond_resched() for every
PAGE_SIZE amount of data. This makes the behavior more consistent with
expectations, and should mitigate the impact of Jann's fix for the
age-old signal check bug.

---- test program ----

  #include <unistd.h>
  #include <signal.h>
  #include <stdio.h>
  #include <sys/random.h>

  static unsigned char x[~0U];

  static void handle(int) { }

  int main(int argc, char *argv[])
  {
    pid_t pid = getpid(), child;
    signal(SIGUSR1, handle);
    if (!(child = fork())) {
      for (;;)
        kill(pid, SIGUSR1);
    }
    pause();
    printf("interrupted after reading %zd bytes\n", getrandom(x, sizeof(x), 0));
    kill(child, SIGTERM);
    return 0;
  }

Cc: Jann Horn <jannh@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-07 01:36:37 +02:00
Jann Horn 1448769c9c random: check for signal_pending() outside of need_resched() check
signal_pending() checks TIF_NOTIFY_SIGNAL and TIF_SIGPENDING, which
signal that the task should bail out of the syscall when possible. This
is a separate concept from need_resched(), which checks
TIF_NEED_RESCHED, signaling that the task should preempt.

In particular, with the current code, the signal_pending() bailout
probably won't work reliably.

Change this to look like other functions that read lots of data, such as
read_zero().

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-06 15:09:33 +02:00
Jason A. Donenfeld aba120cc10 random: do not allow user to keep crng key around on stack
The fast key erasure RNG design relies on the key that's used to be used
and then discarded. We do this, making judicious use of
memzero_explicit().  However, reads to /dev/urandom and calls to
getrandom() involve a copy_to_user(), and userspace can use FUSE or
userfaultfd, or make a massive call, dynamically remap memory addresses
as it goes, and set the process priority to idle, in order to keep a
kernel stack alive indefinitely. By probing
/proc/sys/kernel/random/entropy_avail to learn when the crng key is
refreshed, a malicious userspace could mount this attack every 5 minutes
thereafter, breaking the crng's forward secrecy.

In order to fix this, we just overwrite the stack's key with the first
32 bytes of the "free" fast key erasure output. If we're returning <= 32
bytes to the user, then we can still return those bytes directly, so
that short reads don't become slower. And for long reads, the difference
is hopefully lost in the amortization, so it doesn't change much, with
that amortization helping variously for medium reads.

We don't need to do this for get_random_bytes() and the various
kernel-space callers, and later, if we ever switch to always batching,
this won't be necessary either, so there's no need to change the API of
these functions.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jann Horn <jannh@google.com>
Fixes: c92e040d57 ("random: add backtracking protection to the CRNG")
Fixes: 186873c549 ("random: use simpler fast key erasure flow on per-cpu keys")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-06 15:05:10 +02:00
Muralidhara M K e1907d3751 x86/amd_nb: Unexport amd_cache_northbridges()
amd_cache_northbridges() is exported by amd_nb.c and is called by
amd64-agp.c and amd64_edac.c modules at module_init() time so that NB
descriptors are properly cached before those drivers can use them.

However, the init_amd_nbs() initcall already does call
amd_cache_northbridges() unconditionally and thus makes sure the NB
descriptors are enumerated.

That initcall is a fs_initcall type which is on the 5th group (starting
from 0) of initcalls that gets run in increasing numerical order by the
init code.

The module_init() call is turned into an __initcall() in the MODULE=n
case and those are device-level initcalls, i.e., group 6.

Therefore, the northbridges caching is already finished by the time
module initialization starts and thus the correct initialization order
is retained.

Unexport amd_cache_northbridges(), update dependent modules to
call amd_nb_num() instead. While at it, simplify the checks in
amd_cache_northbridges().

  [ bp: Heavily massage and *actually* explain why the change is ok. ]

Signed-off-by: Muralidhara M K <muralimk@amd.com>
Signed-off-by: Naveen Krishna Chatradhi <nchatrad@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220324122729.221765-1-nchatrad@amd.com
2022-04-05 19:22:27 +02:00
Jason A. Donenfeld 48bff1053c random: opportunistically initialize on /dev/urandom reads
In 6f98a4bfee ("random: block in /dev/urandom"), we tried to make a
successful try_to_generate_entropy() call *required* if the RNG was not
already initialized. Unfortunately, weird architectures and old
userspaces combined in TCG test harnesses, making that change still not
realistic, so it was reverted in 0313bc278d ("Revert "random: block in
/dev/urandom"").

However, rather than making a successful try_to_generate_entropy() call
*required*, we can instead make it *best-effort*.

If try_to_generate_entropy() fails, it fails, and nothing changes from
the current behavior. If it succeeds, then /dev/urandom becomes safe to
use for free. This way, we don't risk the regression potential that led
to us reverting the required-try_to_generate_entropy() call before.

Practically speaking, this means that at least on x86, /dev/urandom
becomes safe. Probably other architectures with working cycle counters
will also become safe. And architectures with slow or broken cycle
counters at least won't be affected at all by this change.

So it may not be the glorious "all things are unified!" change we were
hoping for initially, but practically speaking, it makes a positive
impact.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-05 16:13:13 +02:00
Jan Varho 527a9867af random: do not split fast init input in add_hwgenerator_randomness()
add_hwgenerator_randomness() tries to only use the required amount of input
for fast init, but credits all the entropy, rather than a fraction of
it. Since it's hard to determine how much entropy is left over out of a
non-unformly random sample, either give it all to fast init or credit
it, but don't attempt to do both. In the process, we can clean up the
injection code to no longer need to return a value.

Signed-off-by: Jan Varho <jan.varho@gmail.com>
[Jason: expanded commit message]
Fixes: 73c7733f12 ("random: do not throw away excess input to crng_fast_load")
Cc: stable@vger.kernel.org # 5.17+, requires af704c856e
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-04-04 19:34:49 +02:00
Linus Torvalds 478f74a3d8 Random number generator fixes for Linux 5.18-rc1.
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Merge tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator fixes from Jason Donenfeld:

 - If a hardware random number generator passes a sufficiently large
   chunk of entropy to random.c during early boot, we now skip the
   "fast_init" business and let it initialize the RNG.

   This makes CONFIG_RANDOM_TRUST_BOOTLOADER=y actually useful.

 - We already have the command line `random.trust_cpu=0/1` option for
   RDRAND, which let distros enable CONFIG_RANDOM_TRUST_CPU=y while
   placating concerns of more paranoid users.

   Now we add `random.trust_bootloader=0/1` so that distros can
   similarly enable CONFIG_RANDOM_TRUST_BOOTLOADER=y.

 - Re-add a comment that got removed by accident in the recent revert.

 - Add the spec-compliant ACPI CID for vmgenid, which Microsoft added to
   the vmgenid spec at Ard's request during earlier review.

 - Restore build-time randomness via the latent entropy plugin, which
   was lost when we transitioned to using a hash function.

* tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  random: mix build-time latent entropy into pool at init
  virt: vmgenid: recognize new CID added by Hyper-V
  random: re-add removed comment about get_random_{u32,u64} reseeding
  random: treat bootloader trust toggle the same way as cpu trust toggle
  random: skip fast_init if hwrng provides large chunk of entropy
2022-03-31 14:51:34 -07:00
Jason A. Donenfeld 1754abb3e7 random: mix build-time latent entropy into pool at init
Prior, the "input_pool_data" array needed no real initialization, and so
it was easy to mark it with __latent_entropy to populate it during
compile-time. In switching to using a hash function, this required us to
specifically initialize it to some specific state, which means we
dropped the __latent_entropy attribute. An unfortunate side effect was
this meant the pool was no longer seeded using compile-time random data.
In order to bring this back, we declare an array in rand_initialize()
with __latent_entropy and call mix_pool_bytes() on that at init, which
accomplishes the same thing as before. We make this __initconst, so that
it doesn't take up space at runtime after init.

Fixes: 6e8ec2552c ("random: use computational hash for entropy extraction")
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-31 16:43:27 -04:00
Linus Torvalds 9ae2a14308 dma-mapping updates for Linux 5.18
- do not zero buffer in set_memory_decrypted (Kirill A. Shutemov)
  - fix return value of dma-debug __setup handlers (Randy Dunlap)
  - swiotlb cleanups (Robin Murphy)
  - remove most remaining users of the pci-dma-compat.h API
    (Christophe JAILLET)
  - share the ABI header for the DMA map_benchmark with userspace
    (Tian Tao)
  - update the maintainer for DMA MAPPING BENCHMARK (Xiang Chen)
  - remove CONFIG_DMA_REMAP (me)
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Merge tag 'dma-mapping-5.18' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - do not zero buffer in set_memory_decrypted (Kirill A. Shutemov)

 - fix return value of dma-debug __setup handlers (Randy Dunlap)

 - swiotlb cleanups (Robin Murphy)

 - remove most remaining users of the pci-dma-compat.h API
   (Christophe JAILLET)

 - share the ABI header for the DMA map_benchmark with userspace
   (Tian Tao)

 - update the maintainer for DMA MAPPING BENCHMARK (Xiang Chen)

 - remove CONFIG_DMA_REMAP (me)

* tag 'dma-mapping-5.18' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: benchmark: extract a common header file for map_benchmark definition
  dma-debug: fix return value of __setup handlers
  dma-mapping: remove CONFIG_DMA_REMAP
  media: v4l2-pci-skeleton: Remove usage of the deprecated "pci-dma-compat.h" API
  rapidio/tsi721: Remove usage of the deprecated "pci-dma-compat.h" API
  sparc: Remove usage of the deprecated "pci-dma-compat.h" API
  agp/intel: Remove usage of the deprecated "pci-dma-compat.h" API
  alpha: Remove usage of the deprecated "pci-dma-compat.h" API
  MAINTAINERS: update maintainer list of DMA MAPPING BENCHMARK
  swiotlb: simplify array allocation
  swiotlb: tidy up includes
  swiotlb: simplify debugfs setup
  swiotlb: do not zero buffer in set_memory_decrypted()
2022-03-29 08:50:14 -07:00
Linus Torvalds a701f370b5 xen: branch for v5.18-rc1
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Merge tag 'for-linus-5.18-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:

 - A bunch of minor cleanups

 - A fix for kexec in Xen dom0 when executed on a high cpu number

 - A fix for resuming after suspend of a Xen guest with assigned PCI
   devices

 - A fix for a crash due to not disabled preemption when resuming as Xen
   dom0

* tag 'for-linus-5.18-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: fix is_xen_pmu()
  xen: don't hang when resuming PCI device
  arch:x86:xen: Remove unnecessary assignment in xen_apic_read()
  xen/grant-table: remove readonly parameter from functions
  xen/grant-table: remove gnttab_*transfer*() functions
  drivers/xen: use helper macro __ATTR_RW
  x86/xen: Fix kerneldoc warning
  xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32
  xen: use time_is_before_eq_jiffies() instead of open coding it
2022-03-28 14:32:39 -07:00
Linus Torvalds 02e2af20f4 Char/Misc and other driver updates for 5.18-rc1
Here is the big set of char/misc and other small driver subsystem
 updates for 5.18-rc1.
 
 Included in here are merges from driver subsystems which contain:
 	- iio driver updates and new drivers
 	- fsi driver updates
 	- fpga driver updates
 	- habanalabs driver updates and support for new hardware
 	- soundwire driver updates and new drivers
 	- phy driver updates and new drivers
 	- coresight driver updates
 	- icc driver updates
 
 Individual changes include:
 	- mei driver updates
 	- interconnect driver updates
 	- new PECI driver subsystem added
 	- vmci driver updates
 	- lots of tiny misc/char driver updates
 
 There will be two merge conflicts with your tree, one in MAINTAINERS
 which is obvious to fix up, and one in drivers/phy/freescale/Kconfig
 which also should be easy to resolve.
 
 All of these have been in linux-next for a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other small driver subsystem
  updates for 5.18-rc1.

  Included in here are merges from driver subsystems which contain:

   - iio driver updates and new drivers

   - fsi driver updates

   - fpga driver updates

   - habanalabs driver updates and support for new hardware

   - soundwire driver updates and new drivers

   - phy driver updates and new drivers

   - coresight driver updates

   - icc driver updates

  Individual changes include:

   - mei driver updates

   - interconnect driver updates

   - new PECI driver subsystem added

   - vmci driver updates

   - lots of tiny misc/char driver updates

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits)
  firmware: google: Properly state IOMEM dependency
  kgdbts: fix return value of __setup handler
  firmware: sysfb: fix platform-device leak in error path
  firmware: stratix10-svc: add missing callback parameter on RSU
  arm64: dts: qcom: add non-secure domain property to fastrpc nodes
  misc: fastrpc: Add dma handle implementation
  misc: fastrpc: Add fdlist implementation
  misc: fastrpc: Add helper function to get list and page
  misc: fastrpc: Add support to secure memory map
  dt-bindings: misc: add fastrpc domain vmid property
  misc: fastrpc: check before loading process to the DSP
  misc: fastrpc: add secure domain support
  dt-bindings: misc: add property to support non-secure DSP
  misc: fastrpc: Add support to get DSP capabilities
  misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP
  misc: fastrpc: separate fastrpc device from channel context
  dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells
  dt-bindings: nvmem: make "reg" property optional
  nvmem: brcm_nvram: parse NVRAM content into NVMEM cells
  nvmem: dt-bindings: Fix the error of dt-bindings check
  ...
2022-03-28 12:27:35 -07:00
Linus Torvalds 52d543b549 Minor fixes for IPMI
Little fixes for various things people have noticed.
 
 One enhancement, the IPMI over IPMB (I2c) is modified to allow it to
 take a separate sender and receiver device.  The Raspberry Pi has an
 I2C slave device that cannot send.
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Merge tag 'for-linus-5.17-1' of https://github.com/cminyard/linux-ipmi

Pull IPMI updates from Corey Minyard:

 - Little fixes for various things people have noticed.

 - One enhancement, the IPMI over IPMB (I2c) is modified to allow it to
   take a separate sender and receiver device. The Raspberry Pi has an
   I2C slave device that cannot send.

* tag 'for-linus-5.17-1' of https://github.com/cminyard/linux-ipmi:
  ipmi: initialize len variable
  ipmi: kcs: aspeed: Remove old bindings support
  ipmi:ipmb: Add the ability to have a separate slave and master device
  ipmi:ipmi_ipmb: Unregister the SMI on remove
  ipmi: kcs: aspeed: Add AST2600 compatible string
  ipmi: ssif: replace strlcpy with strscpy
  ipmi/watchdog: Constify ident
  ipmi: Add the git repository to the MAINTAINERS file
2022-03-25 17:46:22 -07:00
Jason A. Donenfeld dd7aa36e53 random: re-add removed comment about get_random_{u32,u64} reseeding
The comment about get_random_{u32,u64}() not invoking reseeding got
added in an unrelated commit, that then was recently reverted by
0313bc278d ("Revert "random: block in /dev/urandom""). So this adds
that little comment snippet back, and improves the wording a bit too.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-25 08:49:40 -06:00
Jason A. Donenfeld d97c68d178 random: treat bootloader trust toggle the same way as cpu trust toggle
If CONFIG_RANDOM_TRUST_CPU is set, the RNG initializes using RDRAND.
But, the user can disable (or enable) this behavior by setting
`random.trust_cpu=0/1` on the kernel command line. This allows system
builders to do reasonable things while avoiding howls from tinfoil
hatters. (Or vice versa.)

CONFIG_RANDOM_TRUST_BOOTLOADER is basically the same thing, but regards
the seed passed via EFI or device tree, which might come from RDRAND or
a TPM or somewhere else. In order to allow distros to more easily enable
this while avoiding those same howls (or vice versa), this commit adds
the corresponding `random.trust_bootloader=0/1` toggle.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Graham Christensen <graham@grahamc.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://github.com/NixOS/nixpkgs/pull/165355
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-25 08:49:40 -06:00
Jason A. Donenfeld af704c856e random: skip fast_init if hwrng provides large chunk of entropy
At boot time, EFI calls add_bootloader_randomness(), which in turn calls
add_hwgenerator_randomness(). Currently add_hwgenerator_randomness()
feeds the first 64 bytes of randomness to the "fast init"
non-crypto-grade phase. But if add_hwgenerator_randomness() gets called
with more than POOL_MIN_BITS of entropy, there's no point in passing it
off to the "fast init" stage, since that's enough entropy to bootstrap
the real RNG. The "fast init" stage is just there to provide _something_
in the case where we don't have enough entropy to properly bootstrap the
RNG. But if we do have enough entropy to bootstrap the RNG, the current
logic doesn't serve a purpose. So, in the case where we're passed
greater than or equal to POOL_MIN_BITS of entropy, this commit makes us
skip the "fast init" phase.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-25 08:49:40 -06:00
Linus Torvalds b14ffae378 drm for 5.18-rc1
dma-buf:
 - rename dma-buf-map to iosys-map
 
 core:
 - move buddy allocator to core
 - add pci/platform init macros
 - improve EDID parser deep color handling
 - EDID timing type 7 support
 - add GPD Win Max quirk
 - add yes/no helpers to string_helpers
 - flatten syncobj chains
 - add nomodeset support to lots of drivers
 - improve fb-helper clipping support
 - add default property value interface
 
 fbdev:
 - improve fbdev ops speed
 
 ttm:
 - add a backpointer from ttm bo->ttm resource
 
 dp:
 - move displayport headers
 - add a dp helper module
 
 bridge:
 - anx7625 atomic support, HDCP support
 
 panel:
 - split out panel-lvds and lvds bindings
 - find panels in OF subnodes
 
 privacy:
 - add chromeos privacy screen support
 
 fb:
 - hot unplug fw fb on forced removal
 
 simpledrm:
 - request region instead of marking ioresource busy
 - add panel oreintation property
 
 udmabuf:
 - fix oops with 0 pages
 
 amdgpu:
 - power management code cleanup
 - Enable freesync video mode by default
 - RAS code cleanup
 - Improve VRAM access for debug using SDMA
 - SR-IOV rework special register access and fixes
 - profiling power state request ioctl
 - expose IP discovery via sysfs
 - Cyan skillfish updates
 - GC 10.3.7, SDMA 5.2.7, DCN 3.1.6 updates
 - expose benchmark tests via debugfs
 - add module param to disable XGMI for testing
 - GPU reset debugfs register dumping support
 
 amdkfd:
 - CRIU support
 - SDMA queue fixes
 
 radeon:
 - UVD suspend fix
 - iMac backlight fix
 
 i915:
 - minimal parallel submission for execlists
 - DG2-G12 subplatform added
 - DG2 programming workarounds
 - DG2 accelerated migration support
 - flat CCS and CCS engine support for XeHP
 - initial small BAR support
 - drop fake LMEM support
 - ADL-N PCH support
 - bigjoiner updates
 - introduce VMA resources and async unbinding
 - register definitions cleanups
 - multi-FBC refactoring
 - DG1 OPROM over SPI support
 - ADL-N platform enabling
 - opregion mailbox #5 support
 - DP MST ESI improvements
 - drm device based logging
 - async flip optimisation for DG2
 - CPU arch abstraction fixes
 - improve GuC ADS init to work on aarch64
 - tweak TTM LRU priority hint
 - GuC 69.0.3 support
 - remove short term execbuf pins
 
 nouveau:
 - higher DP/eDP bitrates
 - backlight fixes
 
 msm:
 - dpu + dp support for sc8180x
 - dp support for sm8350
 - dpu + dsi support for qcm2290
 - 10nm dsi phy tuning support
 - bridge support for dp encoder
 - gpu support for additional 7c3 SKUs
 
 ingenic:
 - HDMI support for JZ4780
 - aux channel EDID support
 
 ast:
 - AST2600 support
 - add wide screen support
 - create DP/DVI connectors
 
 omapdrm:
 - fix implicit dma_buf fencing
 
 vc4:
 - add CSC + full range support
 - better display firmware handoff
 
 panfrost:
 - add initial dual-core GPU support
 
 stm:
 - new revision support
 - fb handover support
 
 mediatek:
 - transfer display binding document to yaml format.
 - add mt8195 display device binding.
 - allow commands to be sent during video mode.
 - add wait_for_event for crtc disable by cmdq.
 
 tegra:
 - YUV format support
 
 rcar-du:
 - LVDS support for M3-W+ (R8A77961)
 
 exynos:
 - BGR pixel format for FIMD device
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Merge tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm

Pull drm updates from Dave Airlie:
 "Lots of work all over, Intel improving DG2 support, amdkfd CRIU
  support, msm new hw support, and faster fbdev support.

  dma-buf:
   - rename dma-buf-map to iosys-map

  core:
   - move buddy allocator to core
   - add pci/platform init macros
   - improve EDID parser deep color handling
   - EDID timing type 7 support
   - add GPD Win Max quirk
   - add yes/no helpers to string_helpers
   - flatten syncobj chains
   - add nomodeset support to lots of drivers
   - improve fb-helper clipping support
   - add default property value interface

  fbdev:
   - improve fbdev ops speed

  ttm:
   - add a backpointer from ttm bo->ttm resource

  dp:
   - move displayport headers
   - add a dp helper module

  bridge:
   - anx7625 atomic support, HDCP support

  panel:
   - split out panel-lvds and lvds bindings
   - find panels in OF subnodes

  privacy:
   - add chromeos privacy screen support

  fb:
   - hot unplug fw fb on forced removal

  simpledrm:
   - request region instead of marking ioresource busy
   - add panel oreintation property

  udmabuf:
   - fix oops with 0 pages

  amdgpu:
   - power management code cleanup
   - Enable freesync video mode by default
   - RAS code cleanup
   - Improve VRAM access for debug using SDMA
   - SR-IOV rework special register access and fixes
   - profiling power state request ioctl
   - expose IP discovery via sysfs
   - Cyan skillfish updates
   - GC 10.3.7, SDMA 5.2.7, DCN 3.1.6 updates
   - expose benchmark tests via debugfs
   - add module param to disable XGMI for testing
   - GPU reset debugfs register dumping support

  amdkfd:
   - CRIU support
   - SDMA queue fixes

  radeon:
   - UVD suspend fix
   - iMac backlight fix

  i915:
   - minimal parallel submission for execlists
   - DG2-G12 subplatform added
   - DG2 programming workarounds
   - DG2 accelerated migration support
   - flat CCS and CCS engine support for XeHP
   - initial small BAR support
   - drop fake LMEM support
   - ADL-N PCH support
   - bigjoiner updates
   - introduce VMA resources and async unbinding
   - register definitions cleanups
   - multi-FBC refactoring
   - DG1 OPROM over SPI support
   - ADL-N platform enabling
   - opregion mailbox #5 support
   - DP MST ESI improvements
   - drm device based logging
   - async flip optimisation for DG2
   - CPU arch abstraction fixes
   - improve GuC ADS init to work on aarch64
   - tweak TTM LRU priority hint
   - GuC 69.0.3 support
   - remove short term execbuf pins

  nouveau:
   - higher DP/eDP bitrates
   - backlight fixes

  msm:
   - dpu + dp support for sc8180x
   - dp support for sm8350
   - dpu + dsi support for qcm2290
   - 10nm dsi phy tuning support
   - bridge support for dp encoder
   - gpu support for additional 7c3 SKUs

  ingenic:
   - HDMI support for JZ4780
   - aux channel EDID support

  ast:
   - AST2600 support
   - add wide screen support
   - create DP/DVI connectors

  omapdrm:
   - fix implicit dma_buf fencing

  vc4:
   - add CSC + full range support
   - better display firmware handoff

  panfrost:
   - add initial dual-core GPU support

  stm:
   - new revision support
   - fb handover support

  mediatek:
   - transfer display binding document to yaml format.
   - add mt8195 display device binding.
   - allow commands to be sent during video mode.
   - add wait_for_event for crtc disable by cmdq.

  tegra:
   - YUV format support

  rcar-du:
   - LVDS support for M3-W+ (R8A77961)

  exynos:
   - BGR pixel format for FIMD device"

* tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm: (1529 commits)
  drm/i915/display: Do not re-enable PSR after it was marked as not reliable
  drm/i915/display: Fix HPD short pulse handling for eDP
  drm/amdgpu: Use drm_mode_copy()
  drm/radeon: Use drm_mode_copy()
  drm/amdgpu: Use ternary operator in `vcn_v1_0_start()`
  drm/amdgpu: Remove pointless on stack mode copies
  drm/amd/pm: fix indenting in __smu_cmn_reg_print_error()
  drm/amdgpu/dc: fix typos in comments
  drm/amdgpu: fix typos in comments
  drm/amd/pm: fix typos in comments
  drm/amdgpu: Add stolen reserved memory for MI25 SRIOV.
  drm/amdgpu: Merge get_reserved_allocation to get_vbios_allocations.
  drm/amdkfd: evict svm bo worker handle error
  drm/amdgpu/vcn: fix vcn ring test failure in igt reload test
  drm/amdgpu: only allow secure submission on rings which support that
  drm/amdgpu: fixed the warnings reported by kernel test robot
  drm/amd/display: 3.2.177
  drm/amd/display: [FW Promotion] Release 0.0.108.0
  drm/amd/display: Add save/restore PANEL_PWRSEQ_REF_DIV2
  drm/amd/display: Wait for hubp read line for Pollock
  ...
2022-03-24 16:19:43 -07:00
Linus Torvalds b4bc93bd76 ARM driver updates for 5.18
There are a few separately maintained driver subsystems that we merge through
 the SoC tree, notable changes are:
 
  - Memory controller updates, mainly for Tegra and Mediatek SoCs,
    and clarifications for the memory controller DT bindings
 
  - SCMI firmware interface updates, in particular a new transport based
    on OPTEE and support for atomic operations.
 
  - Cleanups to the TEE subsystem, refactoring its memory management
 
 For SoC specific drivers without a separate subsystem, changes include
 
  - Smaller updates and fixes for TI, AT91/SAMA5, Qualcomm and NXP
    Layerscape SoCs.
 
  - Driver support for Microchip SAMA5D29, Tesla FSD, Renesas RZ/G2L,
    and Qualcomm SM8450.
 
  - Better power management on Mediatek MT81xx, NXP i.MX8MQ
    and older NVIDIA Tegra chips
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Merge tag 'arm-drivers-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

Pull ARM driver updates from Arnd Bergmann:
 "There are a few separately maintained driver subsystems that we merge
  through the SoC tree, notable changes are:

   - Memory controller updates, mainly for Tegra and Mediatek SoCs, and
     clarifications for the memory controller DT bindings

   - SCMI firmware interface updates, in particular a new transport
     based on OPTEE and support for atomic operations.

   - Cleanups to the TEE subsystem, refactoring its memory management

  For SoC specific drivers without a separate subsystem, changes include

   - Smaller updates and fixes for TI, AT91/SAMA5, Qualcomm and NXP
     Layerscape SoCs.

   - Driver support for Microchip SAMA5D29, Tesla FSD, Renesas RZ/G2L,
     and Qualcomm SM8450.

   - Better power management on Mediatek MT81xx, NXP i.MX8MQ and older
     NVIDIA Tegra chips"

* tag 'arm-drivers-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (154 commits)
  ARM: spear: fix typos in comments
  soc/microchip: fix invalid free in mpfs_sys_controller_delete
  soc: s4: Add support for power domains controller
  dt-bindings: power: add Amlogic s4 power domains bindings
  ARM: at91: add support in soc driver for new SAMA5D29
  soc: mediatek: mmsys: add sw0_rst_offset in mmsys driver data
  dt-bindings: memory: renesas,rpc-if: Document RZ/V2L SoC
  memory: emif: check the pointer temp in get_device_details()
  memory: emif: Add check for setup_interrupts
  dt-bindings: arm: mediatek: mmsys: add support for MT8186
  dt-bindings: mediatek: add compatible for MT8186 pwrap
  soc: mediatek: pwrap: add pwrap driver for MT8186 SoC
  soc: mediatek: mmsys: add mmsys reset control for MT8186
  soc: mediatek: mtk-infracfg: Disable ACP on MT8192
  soc: ti: k3-socinfo: Add AM62x JTAG ID
  soc: mediatek: add MTK mutex support for MT8186
  soc: mediatek: mmsys: add mt8186 mmsys routing table
  soc: mediatek: pm-domains: Add support for mt8186
  dt-bindings: power: Add MT8186 power domains
  soc: mediatek: pm-domains: Add support for mt8195
  ...
2022-03-23 18:23:13 -07:00
Linus Torvalds 0313bc278d Revert "random: block in /dev/urandom"
This reverts commit 6f98a4bfee.

It turns out we still can't do this.  Way too many platforms that don't
have any real source of randomness at boot and no jitter entropy because
they don't even have a cycle counter.

As reported by Guenter Roeck:

 "This causes a large number of qemu boot test failures for various
  architectures (arm, m68k, microblaze, sparc32, xtensa are the ones I
  observed).

  Common denominator is that boot hangs at 'Saving random seed:'"

This isn't hugely unexpected - we tried it, it failed, so now we'll
revert it.

Link: https://lore.kernel.org/all/20220322155820.GA1745955@roeck-us.net/
Reported-and-bisected-by: Guenter Roeck <linux@roeck-us.net>
Cc: Jason Donenfeld <Jason@zx2c4.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-22 09:17:20 -07:00
Linus Torvalds 8565d64430 bounds-fixes updates for v5.18-rc1
- Various buffer and array bounds related fixes
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Merge tag 'bounds-fixes-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull bounds fixes from Kees Cook:
 "These are a handful of buffer and array bounds fixes that I've been
  carrying in preparation for the coming memcpy improvements and the
  enabling of '-Warray-bounds' globally.

  There are additional similar fixes in other maintainer's trees, but
  these ended up getting carried by me. :)"

* tag 'bounds-fixes-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  media: omap3isp: Use struct_group() for memcpy() region
  tpm: vtpm_proxy: Check length to avoid compiler warning
  alpha: Silence -Warray-bounds warnings
  m68k: cmpxchg: Dereference matching size
  intel_th: msu: Use memset_startat() for clearing hw header
  KVM: x86: Replace memset() "optimization" with normal per-field writes
2022-03-21 19:58:27 -07:00
Linus Torvalds ad9c6ee642 spi: Updates for v5.18
The overwhelming bulk of this pull request is a change from Uwe
 Kleine-König which changes the return type of the remove() function to
 void as part of some wider work he's doing to do this for all bus types,
 causing updates to most SPI device drivers.  The branch with that on has
 been cross merged with a couple of other trees which added new SPI
 drivers this cycle, I'm not expecting any build issues resulting from
 the change.
 
 Otherwise it's been a relatively quiet release with some new device
 support, a few minor features and the welcome completion of the
 conversion of the subsystem to use GPIO descriptors rather than numbers:
 
  - Change return type of remove() to void.
  - Completion of the conversion of SPI controller drivers to use GPIO
    descriptors rather than numbers.
  - Quite a few DT schema conversions.
  - Support for multiple SPI devices on a bus in ACPI systems.
  - Big overhaul of the PXA2xx SPI driver.
  - Support for AMD AMDI0062, Intel Raptor Lake, Mediatek MT7986 and
    MT8186, nVidia Tegra210 and Tegra234, Renesas RZ/V2L, Tesla FSD and
    Sunplus SP7021.
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Merge tag 'spi-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi updates from Mark Brown:
 "The overwhelming bulk of this pull request is a change from Uwe
  Kleine-König which changes the return type of the remove() function to
  void as part of some wider work he's doing to do this for all bus
  types, causing updates to most SPI device drivers. The branch with
  that on has been cross merged with a couple of other trees which added
  new SPI drivers this cycle, I'm not expecting any build issues
  resulting from the change.

  Otherwise it's been a relatively quiet release with some new device
  support, a few minor features and the welcome completion of the
  conversion of the subsystem to use GPIO descriptors rather than
  numbers:

   - Change return type of remove() to void.

   - Completion of the conversion of SPI controller drivers to use GPIO
     descriptors rather than numbers.

   - Quite a few DT schema conversions.

   - Support for multiple SPI devices on a bus in ACPI systems.

   - Big overhaul of the PXA2xx SPI driver.

   - Support for AMD AMDI0062, Intel Raptor Lake, Mediatek MT7986 and
     MT8186, nVidia Tegra210 and Tegra234, Renesas RZ/V2L, Tesla FSD and
     Sunplus SP7021"

[ And this is obviously where that spi change that snuck into the
  regulator tree _should_ have been :^]

* tag 'spi-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (124 commits)
  spi: fsi: Implement a timeout for polling status
  spi: Fix erroneous sgs value with min_t()
  spi: tegra20: Use of_device_get_match_data()
  spi: mediatek: add ipm design support for MT7986
  spi: Add compatible for MT7986
  spi: sun4i: fix typos in comments
  spi: mediatek: support tick_delay without enhance_timing
  spi: Update clock-names property for arm pl022
  spi: rockchip-sfc: fix platform_get_irq.cocci warning
  spi: s3c64xx: Add spi port configuration for Tesla FSD SoC
  spi: dt-bindings: samsung: Add fsd spi compatible
  spi: topcliff-pch: Prevent usage of potentially stale DMA device
  spi: tegra210-quad: combined sequence mode
  spi: tegra210-quad: add acpi support
  spi: npcm-fiu: Fix typo ("npxm")
  spi: Fix Tegra QSPI example
  spi: qup: replace spin_lock_irqsave by spin_lock in hard IRQ
  spi: cadence: fix platform_get_irq.cocci warning
  spi: Update NXP Flexspi maintainer details
  dt-bindings: mfd: maxim,max77802: Convert to dtschema
  ...
2022-03-21 18:33:57 -07:00
Linus Torvalds 616355cc81 for-5.18/block-2022-03-18
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Merge tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:

 - BFQ cleanups and fixes (Yu, Zhang, Yahu, Paolo)

 - blk-rq-qos completion fix (Tejun)

 - blk-cgroup merge fix (Tejun)

 - Add offline error return value to distinguish it from an IO error on
   the device (Song)

 - IO stats fixes (Zhang, Christoph)

 - blkcg refcount fixes (Ming, Yu)

 - Fix for indefinite dispatch loop softlockup (Shin'ichiro)

 - blk-mq hardware queue management improvements (Ming)

 - sbitmap dead code removal (Ming, John)

 - Plugging merge improvements (me)

 - Show blk-crypto capabilities in sysfs (Eric)

 - Multiple delayed queue run improvement (David)

 - Block throttling fixes (Ming)

 - Start deprecating auto module loading based on dev_t (Christoph)

 - bio allocation improvements (Christoph, Chaitanya)

 - Get rid of bio_devname (Christoph)

 - bio clone improvements (Christoph)

 - Block plugging improvements (Christoph)

 - Get rid of genhd.h header (Christoph)

 - Ensure drivers use appropriate flush helpers (Christoph)

 - Refcounting improvements (Christoph)

 - Queue initialization and teardown improvements (Ming, Christoph)

 - Misc fixes/improvements (Barry, Chaitanya, Colin, Dan, Jiapeng,
   Lukas, Nian, Yang, Eric, Chengming)

* tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-block: (127 commits)
  block: cancel all throttled bios in del_gendisk()
  block: let blkcg_gq grab request queue's refcnt
  block: avoid use-after-free on throttle data
  block: limit request dispatch loop duration
  block/bfq-iosched: Fix spelling mistake "tenative" -> "tentative"
  sr: simplify the local variable initialization in sr_block_open()
  block: don't merge across cgroup boundaries if blkcg is enabled
  block: fix rq-qos breakage from skipping rq_qos_done_bio()
  block: flush plug based on hardware and software queue order
  block: ensure plug merging checks the correct queue at least once
  block: move rq_qos_exit() into disk_release()
  block: do more work in elevator_exit
  block: move blk_exit_queue into disk_release
  block: move q_usage_counter release into blk_queue_release
  block: don't remove hctx debugfs dir from blk_mq_exit_queue
  block: move blkcg initialization/destroy into disk allocation/release handler
  sr: implement ->free_disk to simplify refcounting
  sd: implement ->free_disk to simplify refcounting
  sd: delay calling free_opal_dev
  sd: call sd_zbc_release_disk before releasing the scsi_device reference
  ...
2022-03-21 16:48:55 -07:00
Linus Torvalds 93e220a62d Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
 "API:
   - hwrng core now credits for low-quality RNG devices.

  Algorithms:
   - Optimisations for neon aes on arm/arm64.
   - Add accelerated crc32_be on arm64.
   - Add ffdheXYZ(dh) templates.
   - Disallow hmac keys < 112 bits in FIPS mode.
   - Add AVX assembly implementation for sm3 on x86.

  Drivers:
   - Add missing local_bh_disable calls for crypto_engine callback.
   - Ensure BH is disabled in crypto_engine callback path.
   - Fix zero length DMA mappings in ccree.
   - Add synchronization between mailbox accesses in octeontx2.
   - Add Xilinx SHA3 driver.
   - Add support for the TDES IP available on sama7g5 SoC in atmel"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (137 commits)
  crypto: xilinx - Turn SHA into a tristate and allow COMPILE_TEST
  MAINTAINERS: update HPRE/SEC2/TRNG driver maintainers list
  crypto: dh - Remove the unused function dh_safe_prime_dh_alg()
  hwrng: nomadik - Change clk_disable to clk_disable_unprepare
  crypto: arm64 - cleanup comments
  crypto: qat - fix initialization of pfvf rts_map_msg structures
  crypto: qat - fix initialization of pfvf cap_msg structures
  crypto: qat - remove unneeded assignment
  crypto: qat - disable registration of algorithms
  crypto: hisilicon/qm - fix memset during queues clearing
  crypto: xilinx: prevent probing on non-xilinx hardware
  crypto: marvell/octeontx - Use swap() instead of open coding it
  crypto: ccree - Fix use after free in cc_cipher_exit()
  crypto: ccp - ccp_dmaengine_unregister release dma channels
  crypto: octeontx2 - fix missing unlock
  hwrng: cavium - fix NULL but dereferenced coccicheck error
  crypto: cavium/nitrox - don't cast parameter in bit operations
  crypto: vmx - add missing dependencies
  MAINTAINERS: Add maintainer for Xilinx ZynqMP SHA3 driver
  crypto: xilinx - Add Xilinx SHA3 driver
  ...
2022-03-21 16:02:36 -07:00
Linus Torvalds 5628b8de12 Random number generator changes for Linux 5.18-rc1.
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Merge tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "There have been a few important changes to the RNG's crypto, but the
  intent for 5.18 has been to shore up the existing design as much as
  possible with modern cryptographic functions and proven constructions,
  rather than actually changing up anything fundamental to the RNG's
  design.

  So it's still the same old RNG at its core as before: it still counts
  entropy bits, and collects from the various sources with the same
  heuristics as before, and so forth. However, the cryptographic
  algorithms that transform that entropic data into safe random numbers
  have been modernized.

  Just as important, if not more, is that the code has been cleaned up
  and re-documented. As one of the first drivers in Linux, going back to
  1.3.30, its general style and organization was showing its age and
  becoming both a maintenance burden and an auditability impediment.

  Hopefully this provides a more solid foundation to build on for the
  future. I encourage you to open up the file in full, and maybe you'll
  remark, "oh, that's what it's doing," and enjoy reading it. That, at
  least, is the eventual goal, which this pull begins working toward.

  Here's a summary of the various patches in this pull:

   - /dev/urandom and /dev/random now do the same thing, per the patch
     we discussed on the list. I think this is worth trying out. If it
     does appear problematic, I've made sure to keep it standalone and
     revertible without any conflicts.

   - Fixes and cleanups for numerous integer type problems, locking
     issues, and general code quality concerns.

   - The input pool's LFSR has been replaced with a cryptographically
     secure hash function, which has security and performance benefits
     alike, and consequently allows us to count entropy bits linearly.

   - The pre-init injection now uses a real hash function too, instead
     of an LFSR or vanilla xor.

   - The interrupt handler's fast_mix() function now uses one round of
     SipHash, rather than the fake crypto that was there before.

   - All additions of RDRAND and RDSEED now go through the input pool's
     hash function, in part to mitigate ridiculous hypothetical CPU
     backdoors, but more so to have a consistent interface for ingesting
     entropy that's easy to analyze, making everything happen one way,
     instead of a potpourri of different ways.

   - The crng now works on per-cpu data, while also being in accordance
     with the actual "fast key erasure RNG" design. This allows us to
     fix several boot-time race complications associated with the prior
     dynamically allocated model, eliminates much locking, and makes our
     backtrack protection more robust.

   - Batched entropy now erases doled out values so that it's backtrack
     resistant.

   - Working closely with Sebastian, the interrupt handler no longer
     needs to take any locks at all, as we punt the
     synchronized/expensive operations to a workqueue. This is
     especially nice for PREEMPT_RT, where taking spinlocks in irq
     context is problematic. It also makes the handler faster for the
     rest of us.

   - Also working with Sebastian, we now do the right thing on CPU
     hotplug, so that we don't use stale entropy or fail to accumulate
     new entropy when CPUs come back online.

   - We handle virtual machines that fork / clone / snapshot, using the
     "vmgenid" ACPI specification for retrieving a unique new RNG seed,
     which we can use to also make WireGuard (and in the future, other
     things) safe across VM forks.

   - Around boot time, we now try to reseed more often if enough entropy
     is available, before settling on the usual 5 minute schedule.

   - Last, but certainly not least, the documentation in the file has
     been updated considerably"

* tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (60 commits)
  random: check for signal and try earlier when generating entropy
  random: reseed more often immediately after booting
  random: make consistent usage of crng_ready()
  random: use SipHash as interrupt entropy accumulator
  wireguard: device: clear keys on VM fork
  random: provide notifier for VM fork
  random: replace custom notifier chain with standard one
  random: do not export add_vmfork_randomness() unless needed
  virt: vmgenid: notify RNG of VM fork and supply generation ID
  ACPI: allow longer device IDs
  random: add mechanism for VM forks to reinitialize crng
  random: don't let 644 read-only sysctls be written to
  random: give sysctl_random_min_urandom_seed a more sensible value
  random: block in /dev/urandom
  random: do crng pre-init loading in worker rather than irq
  random: unify cycles_t and jiffies usage and types
  random: cleanup UUID handling
  random: only wake up writers after zap if threshold was passed
  random: round-robin registers as ulong, not u32
  random: clear fast pool, crng, and batches in cpuhp bring up
  ...
2022-03-21 14:55:32 -07:00
Tom Rix 8d10ea152e ipmi: initialize len variable
Clang static analysis reports this issue
ipmi_ssif.c:1731:3: warning: 4th function call
  argument is an uninitialized value
  dev_info(&ssif_info->client->dev,
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The 4th parameter is the 'len' variable.
len is only set by a successful call to do_cmd().
Initialize to len 0.

Signed-off-by: Tom Rix <trix@redhat.com>
Message-Id: <20220320135954.2258545-1-trix@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-03-20 12:37:15 -05:00
Randy Dunlap fefb8a2a94 virtio_console: eliminate anonymous module_init & module_exit
Eliminate anonymous module_init() and module_exit(), which can lead to
confusion or ambiguity when reading System.map, crashes/oops/bugs,
or an initcall_debug log.

Give each of these init and exit functions unique driver-specific
names to eliminate the anonymous names.

Example 1: (System.map)
 ffffffff832fc78c t init
 ffffffff832fc79e t init
 ffffffff832fc8f8 t init

Example 2: (initcall_debug log)
 calling  init+0x0/0x12 @ 1
 initcall init+0x0/0x12 returned 0 after 15 usecs
 calling  init+0x0/0x60 @ 1
 initcall init+0x0/0x60 returned 0 after 2 usecs
 calling  init+0x0/0x9a @ 1
 initcall init+0x0/0x9a returned 0 after 74 usecs

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Amit Shah <amit@kernel.org>
Cc: virtualization@lists.linux-foundation.org
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220316192010.19001-3-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 13:45:55 +01:00
Juergen Gross c94b731da2 xen/grant-table: remove readonly parameter from functions
The gnttab_end_foreign_access() family of functions is taking a
"readonly" parameter, which isn't used. Remove it from the function
parameters.

Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2022-03-15 20:34:40 -05:00
Miaoqian Lin 7f0f1f3ef6 hwrng: nomadik - Change clk_disable to clk_disable_unprepare
The corresponding API for clk_prepare_enable is clk_disable_unprepare,
other than clk_disable_unprepare.

Fix this by changing clk_disable to clk_disable_unprepare.

Fixes: beca35d05c ("hwrng: nomadik - use clk_prepare_enable()")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-14 14:45:44 +12:00
Jason A. Donenfeld 3e504d2026 random: check for signal and try earlier when generating entropy
Rather than waiting a full second in an interruptable waiter before
trying to generate entropy, try to generate entropy first and wait
second. While waiting one second might give an extra second for getting
entropy from elsewhere, we're already pretty late in the init process
here, and whatever else is generating entropy will still continue to
contribute. This has implications on signal handling: we call
try_to_generate_entropy() from wait_for_random_bytes(), and
wait_for_random_bytes() always uses wait_event_interruptible_timeout()
when waiting, since it's called by userspace code in restartable
contexts, where signals can pend. Since try_to_generate_entropy() now
runs first, if a signal is pending, it's necessary for
try_to_generate_entropy() to check for signals, since it won't hit the
wait until after try_to_generate_entropy() has returned. And even before
this change, when entering a busy loop in try_to_generate_entropy(), we
should have been checking to see if any signals are pending, so that a
process doesn't get stuck in that loop longer than expected.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 20:51:39 -07:00
Jason A. Donenfeld 7a7ff644ae random: reseed more often immediately after booting
In order to chip away at the "premature first" problem, we augment our
existing entropy accounting with more frequent reseedings at boot.

The idea is that at boot, we're getting entropy from various places, and
we're not very sure which of early boot entropy is good and which isn't.
Even when we're crediting the entropy, we're still not totally certain
that it's any good. Since boot is the one time (aside from a compromise)
that we have zero entropy, it's important that we shepherd entropy into
the crng fairly often.

At the same time, we don't want a "premature next" problem, whereby an
attacker can brute force individual bits of added entropy. In lieu of
going full-on Fortuna (for now), we can pick a simpler strategy of just
reseeding more often during the first 5 minutes after boot. This is
still bounded by the 256-bit entropy credit requirement, so we'll skip a
reseeding if we haven't reached that, but in case entropy /is/ coming
in, this ensures that it makes its way into the crng rather rapidly
during these early stages.

Ordinarily we reseed if the previous reseeding is 300 seconds old. This
commit changes things so that for the first 600 seconds of boot time, we
reseed if the previous reseeding is uptime / 2 seconds old. That means
that we'll reseed at the very least double the uptime of the previous
reseeding.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 20:51:21 -07:00
Jason A. Donenfeld a96cfe2d42 random: make consistent usage of crng_ready()
Rather than sometimes checking `crng_init < 2`, we should always use the
crng_ready() macro, so that should we change anything later, it's
consistent. Additionally, that macro already has a likely() around it,
which means we don't need to open code our own likely() and unlikely()
annotations.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld f5eab0e2db random: use SipHash as interrupt entropy accumulator
The current fast_mix() function is a piece of classic mailing list
crypto, where it just sort of sprung up by an anonymous author without a
lot of real analysis of what precisely it was accomplishing. As an ARX
permutation alone, there are some easily searchable differential trails
in it, and as a means of preventing malicious interrupts, it completely
fails, since it xors new data into the entire state every time. It can't
really be analyzed as a random permutation, because it clearly isn't,
and it can't be analyzed as an interesting linear algebraic structure
either, because it's also not that. There really is very little one can
say about it in terms of entropy accumulation. It might diffuse bits,
some of the time, maybe, we hope, I guess. But for the most part, it
fails to accomplish anything concrete.

As a reminder, the simple goal of add_interrupt_randomness() is to
simply accumulate entropy until ~64 interrupts have elapsed, and then
dump it into the main input pool, which uses a cryptographic hash.

It would be nice to have something cryptographically strong in the
interrupt handler itself, in case a malicious interrupt compromises a
per-cpu fast pool within the 64 interrupts / 1 second window, and then
inside of that same window somehow can control its return address and
cycle counter, even if that's a bit far fetched. However, with a very
CPU-limited budget, actually doing that remains an active research
project (and perhaps there'll be something useful for Linux to come out
of it). And while the abundance of caution would be nice, this isn't
*currently* the security model, and we don't yet have a fast enough
solution to make it our security model. Plus there's not exactly a
pressing need to do that. (And for the avoidance of doubt, the actual
cluster of 64 accumulated interrupts still gets dumped into our
cryptographically secure input pool.)

So, for now we are going to stick with the existing interrupt security
model, which assumes that each cluster of 64 interrupt data samples is
mostly non-malicious and not colluding with an infoleaker. With this as
our goal, we have a few more choices, simply aiming to accumulate
entropy, while discarding the least amount of it.

We know from <https://eprint.iacr.org/2019/198> that random oracles,
instantiated as computational hash functions, make good entropy
accumulators and extractors, which is the justification for using
BLAKE2s in the main input pool. As mentioned, we don't have that luxury
here, but we also don't have the same security model requirements,
because we're assuming that there aren't malicious inputs. A
pseudorandom function instance can approximately behave like a random
oracle, provided that the key is uniformly random. But since we're not
concerned with malicious inputs, we can pick a fixed key, which is not
secret, knowing that "nature" won't interact with a sufficiently chosen
fixed key by accident. So we pick a PRF with a fixed initial key, and
accumulate into it continuously, dumping the result every 64 interrupts
into our cryptographically secure input pool.

For this, we make use of SipHash-1-x on 64-bit and HalfSipHash-1-x on
32-bit, which are already in use in the kernel's hsiphash family of
functions and achieve the same performance as the function they replace.
It would be nice to do two rounds, but we don't exactly have the CPU
budget handy for that, and one round alone is already sufficient.

As mentioned, we start with a fixed initial key (zeros is fine), and
allow SipHash's symmetry breaking constants to turn that into a useful
starting point. Also, since we're dumping the result (or half of it on
64-bit so as to tax our hash function the same amount on all platforms)
into the cryptographically secure input pool, there's no point in
finalizing SipHash's output, since it'll wind up being finalized by
something much stronger. This means that all we need to do is use the
ordinary round function word-by-word, as normal SipHash does.
Simplified, the flow is as follows:

Initialize:

    siphash_state_t state;
    siphash_init(&state, key={0, 0, 0, 0});

Update (accumulate) on interrupt:

    siphash_update(&state, interrupt_data_and_timing);

Dump into input pool after 64 interrupts:

    blake2s_update(&input_pool, &state, sizeof(state) / 2);

The result of all of this is that the security model is unchanged from
before -- we assume non-malicious inputs -- yet we now implement that
model with a stronger argument. I would like to emphasize, again, that
the purpose of this commit is to improve the existing design, by making
it analyzable, without changing any fundamental assumptions. There may
well be value down the road in changing up the existing design, using
something cryptographically strong, or simply using a ring buffer of
samples rather than having a fast_mix() at all, or changing which and
how much data we collect each interrupt so that we can use something
linear, or a variety of other ideas. This commit does not invalidate the
potential for those in the future.

For example, in the future, if we're able to characterize the data we're
collecting on each interrupt, we may be able to inch toward information
theoretic accumulators. <https://eprint.iacr.org/2021/523> shows that `s
= ror32(s, 7) ^ x` and `s = ror64(s, 19) ^ x` make very good
accumulators for 2-monotone distributions, which would apply to
timestamp counters, like random_get_entropy() or jiffies, but would not
apply to our current combination of the two values, or to the various
function addresses and register values we mix in. Alternatively,
<https://eprint.iacr.org/2021/1002> shows that max-period linear
functions with no non-trivial invariant subspace make good extractors,
used in the form `s = f(s) ^ x`. However, this only works if the input
data is both identical and independent, and obviously a collection of
address values and counters fails; so it goes with theoretical papers.
Future directions here may involve trying to characterize more precisely
what we actually need to collect in the interrupt handler, and building
something specific around that.

However, as mentioned, the morass of data we're gathering at the
interrupt handler presently defies characterization, and so we use
SipHash for now, which works well and performs well.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld f3c2682bad random: provide notifier for VM fork
Drivers such as WireGuard need to learn when VMs fork in order to clear
sessions. This commit provides a simple notifier_block for that, with a
register and unregister function. When no VM fork detection is compiled
in, this turns into a no-op, similar to how the power notifier works.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld 5acd35487d random: replace custom notifier chain with standard one
We previously rolled our own randomness readiness notifier, which only
has two users in the whole kernel. Replace this with a more standard
atomic notifier block that serves the same purpose with less code. Also
unexport the symbols, because no modules use it, only unconditional
builtins. The only drawback is that it's possible for a notification
handler returning the "stop" code to prevent further processing, but
given that there are only two users, and that we're unexporting this
anyway, that doesn't seem like a significant drawback for the
simplification we receive here.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld a4107d34f9 random: do not export add_vmfork_randomness() unless needed
Since add_vmfork_randomness() is only called from vmgenid.o, we can
guard it in CONFIG_VMGENID, similarly to how we do with
add_disk_randomness() and CONFIG_BLOCK. If we ever have multiple things
calling into add_vmfork_randomness(), we can add another shared Kconfig
symbol for that, but for now, this is good enough. Even though
add_vmfork_randomess() is a pretty small function, removing it means
that there are only calls to crng_reseed(false) and none to
crng_reseed(true), which means the compiler can constant propagate the
false, removing branches from crng_reseed() and its descendants.

Additionally, we don't even need the symbol to be exported if
CONFIG_VMGENID is not a module, so conditionalize that too.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld ae099e8e98 random: add mechanism for VM forks to reinitialize crng
When a VM forks, we must immediately mix in additional information to
the stream of random output so that two forks or a rollback don't
produce the same stream of random numbers, which could have catastrophic
cryptographic consequences. This commit adds a simple API, add_vmfork_
randomness(), for that, by force reseeding the crng.

This has the added benefit of also draining the entropy pool and setting
its timer back, so that any old entropy that was there prior -- which
could have already been used by a different fork, or generally gone
stale -- does not contribute to the accounting of the next 256 bits.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jann Horn <jannh@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld 77553cf8f4 random: don't let 644 read-only sysctls be written to
We leave around these old sysctls for compatibility, and we keep them
"writable" for compatibility, but even after writing, we should keep
reporting the same value. This is consistent with how userspaces tend to
use sysctl_random_write_wakeup_bits, writing to it, and then later
reading from it and using the value.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld d0efdf35a6 random: give sysctl_random_min_urandom_seed a more sensible value
This isn't used by anything or anywhere, but we can't delete it due to
compatibility. So at least give it the correct value of what it's
supposed to be instead of a garbage one.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:56 -07:00
Jason A. Donenfeld 6f98a4bfee random: block in /dev/urandom
This topic has come up countless times, and usually doesn't go anywhere.
This time I thought I'd bring it up with a slightly narrower focus,
updated for some developments over the last three years: we finally can
make /dev/urandom always secure, in light of the fact that our RNG is
now always seeded.

Ever since Linus' 50ee7529ec ("random: try to actively add entropy
rather than passively wait for it"), the RNG does a haveged-style jitter
dance around the scheduler, in order to produce entropy (and credit it)
for the case when we're stuck in wait_for_random_bytes(). How ever you
feel about the Linus Jitter Dance is beside the point: it's been there
for three years and usually gets the RNG initialized in a second or so.

As a matter of fact, this is what happens currently when people use
getrandom(). It's already there and working, and most people have been
using it for years without realizing.

So, given that the kernel has grown this mechanism for seeding itself
from nothing, and that this procedure happens pretty fast, maybe there's
no point any longer in having /dev/urandom give insecure bytes. In the
past we didn't want the boot process to deadlock, which was
understandable. But now, in the worst case, a second goes by, and the
problem is resolved. It seems like maybe we're finally at a point when
we can get rid of the infamous "urandom read hole".

The one slight drawback is that the Linus Jitter Dance relies on random_
get_entropy() being implemented. The first lines of try_to_generate_
entropy() are:

	stack.now = random_get_entropy();
	if (stack.now == random_get_entropy())
		return;

On most platforms, random_get_entropy() is simply aliased to get_cycles().
The number of machines without a cycle counter or some other
implementation of random_get_entropy() in 2022, which can also run a
mainline kernel, and at the same time have a both broken and out of date
userspace that relies on /dev/urandom never blocking at boot is thought
to be exceedingly low. And to be clear: those museum pieces without
cycle counters will continue to run Linux just fine, and even
/dev/urandom will be operable just like before; the RNG just needs to be
seeded first through the usual means, which should already be the case
now.

On systems that really do want unseeded randomness, we already offer
getrandom(GRND_INSECURE), which is in use by, e.g., systemd for seeding
their hash tables at boot. Nothing in this commit would affect
GRND_INSECURE, and it remains the means of getting those types of random
numbers.

This patch goes a long way toward eliminating a long overdue userspace
crypto footgun. After several decades of endless user confusion, we will
finally be able to say, "use any single one of our random interfaces and
you'll be fine. They're all the same. It doesn't matter." And that, I
think, is really something. Finally all of those blog posts and
disagreeing forums and contradictory articles will all become correct
about whatever they happened to recommend, and along with it, a whole
class of vulnerabilities eliminated.

With very minimal downside, we're finally in a position where we can
make this change.

Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Guo Ren <guoren@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: David Laight <David.Laight@aculab.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-03-12 18:00:55 -07:00
James Bottomley fb5abce6b2 tpm: use try_get_ops() in tpm-space.c
As part of the series conversion to remove nested TPM operations:

https://lore.kernel.org/all/20190205224723.19671-1-jarkko.sakkinen@linux.intel.com/

exposure of the chip->tpm_mutex was removed from much of the upper
level code.  In this conversion, tpm2_del_space() was missed.  This
didn't matter much because it's usually called closely after a
converted operation, so there's only a very tiny race window where the
chip can be removed before the space flushing is done which causes a
NULL deref on the mutex.  However, there are reports of this window
being hit in practice, so fix this by converting tpm2_del_space() to
use tpm_try_get_ops(), which performs all the teardown checks before
acquring the mutex.

Cc: stable@vger.kernel.org # 5.4.x
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-03-10 01:47:25 +02:00
Lino Sanfilippo 7e0438f83d tpm: fix reference counting for struct tpm_chip
The following sequence of operations results in a refcount warning:

1. Open device /dev/tpmrm.
2. Remove module tpm_tis_spi.
3. Write a TPM command to the file descriptor opened at step 1.

------------[ cut here ]------------
WARNING: CPU: 3 PID: 1161 at lib/refcount.c:25 kobject_get+0xa0/0xa4
refcount_t: addition on 0; use-after-free.
Modules linked in: tpm_tis_spi tpm_tis_core tpm mdio_bcm_unimac brcmfmac
sha256_generic libsha256 sha256_arm hci_uart btbcm bluetooth cfg80211 vc4
brcmutil ecdh_generic ecc snd_soc_core crc32_arm_ce libaes
raspberrypi_hwmon ac97_bus snd_pcm_dmaengine bcm2711_thermal snd_pcm
snd_timer genet snd phy_generic soundcore [last unloaded: spi_bcm2835]
CPU: 3 PID: 1161 Comm: hold_open Not tainted 5.10.0ls-main-dirty #2
Hardware name: BCM2711
[<c0410c3c>] (unwind_backtrace) from [<c040b580>] (show_stack+0x10/0x14)
[<c040b580>] (show_stack) from [<c1092174>] (dump_stack+0xc4/0xd8)
[<c1092174>] (dump_stack) from [<c0445a30>] (__warn+0x104/0x108)
[<c0445a30>] (__warn) from [<c0445aa8>] (warn_slowpath_fmt+0x74/0xb8)
[<c0445aa8>] (warn_slowpath_fmt) from [<c08435d0>] (kobject_get+0xa0/0xa4)
[<c08435d0>] (kobject_get) from [<bf0a715c>] (tpm_try_get_ops+0x14/0x54 [tpm])
[<bf0a715c>] (tpm_try_get_ops [tpm]) from [<bf0a7d6c>] (tpm_common_write+0x38/0x60 [tpm])
[<bf0a7d6c>] (tpm_common_write [tpm]) from [<c05a7ac0>] (vfs_write+0xc4/0x3c0)
[<c05a7ac0>] (vfs_write) from [<c05a7ee4>] (ksys_write+0x58/0xcc)
[<c05a7ee4>] (ksys_write) from [<c04001a0>] (ret_fast_syscall+0x0/0x4c)
Exception stack(0xc226bfa8 to 0xc226bff0)
bfa0:                   00000000 000105b4 00000003 beafe664 00000014 00000000
bfc0: 00000000 000105b4 000103f8 00000004 00000000 00000000 b6f9c000 beafe684
bfe0: 0000006c beafe648 0001056c b6eb6944
---[ end trace d4b8409def9b8b1f ]---

The reason for this warning is the attempt to get the chip->dev reference
in tpm_common_write() although the reference counter is already zero.

Since commit 8979b02aaf ("tpm: Fix reference count to main device") the
extra reference used to prevent a premature zero counter is never taken,
because the required TPM_CHIP_FLAG_TPM2 flag is never set.

Fix this by moving the TPM 2 character device handling from
tpm_chip_alloc() to tpm_add_char_device() which is called at a later point
in time when the flag has been set in case of TPM2.

Commit fdc915f7f7 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
already introduced function tpm_devs_release() to release the extra
reference but did not implement the required put on chip->devs that results
in the call of this function.

Fix this by putting chip->devs in tpm_chip_unregister().

Finally move the new implementation for the TPM 2 handling into a new
function to avoid multiple checks for the TPM_CHIP_FLAG_TPM2 flag in the
good case and error cases.

Cc: stable@vger.kernel.org
Fixes: fdc915f7f7 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
Fixes: 8979b02aaf ("tpm: Fix reference count to main device")
Co-developed-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-03-08 13:55:52 +02:00
Gustavo A. R. Silva 2dd634664d tpm: xen-tpmfront: Use struct_size() helper
Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worse scenario, could lead to heap overflows.

Also, address the following sparse warning:
drivers/char/tpm/xen-tpmfront.c:131:16: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/160
Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-03-08 10:33:18 +02:00
Tadeusz Struk 2e8e4c8f66 tpm: Fix error handling in async work
When an invalid (non existing) handle is used in a TPM command,
that uses the resource manager interface (/dev/tpmrm0) the resource
manager tries to load it from its internal cache, but fails and
the tpm_dev_transmit returns an -EINVAL error to the caller.
The existing async handler doesn't handle these error cases
currently and the condition in the poll handler never returns
mask with EPOLLIN set.
The result is that the poll call blocks and the application gets stuck
until the user_read_timer wakes it up after 120 sec.
Change the tpm_dev_async_work function to handle error conditions
returned from tpm_dev_transmit they are also reflected in the poll mask
and a correct error code could passed back to the caller.

Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: <linux-integrity@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>

Fixes: 9e1b74a63f ("tpm: add support for nonblocking operation")
Tested-by: Jarkko Sakkinen<jarkko@kernel.org>
Signed-off-by: Tadeusz Struk <tstruk@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-03-08 10:33:17 +02:00
Michael S. Tsirkin 0e7174b9d5 virtio_console: break out of buf poll on remove
A common pattern for device reset is currently:
vdev->config->reset(vdev);
.. cleanup ..

reset prevents new interrupts from arriving and waits for interrupt
handlers to finish.

However if - as is common - the handler queues a work request which is
flushed during the cleanup stage, we have code adding buffers / trying
to get buffers while device is reset. Not good.

This was reproduced by running
	modprobe virtio_console
	modprobe -r virtio_console
in a loop.

Fix this up by calling virtio_break_device + flush before reset.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1786239
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-03-04 08:33:22 -05:00
Wan Jiabing e6205ad58a hwrng: cavium - fix NULL but dereferenced coccicheck error
Fix following coccicheck warning:
./drivers/char/hw_random/cavium-rng-vf.c:182:17-20: ERROR:
pdev is NULL but dereferenced.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:49:22 +12:00
Claudiu Beznea 53e748c275 hwrng: atmel - remove extra line
Remove extra line.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:19 +12:00
Claudiu Beznea c4f51eab6c hwrng: atmel - add runtime pm support
Add runtime PM support.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:19 +12:00
Claudiu Beznea b953188525 hwrng: atmel - use __maybe_unused and pm_ptr() for pm ops
Use __maybe_unused and pm_ptr() for pm ops.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:19 +12:00
Claudiu Beznea 9fbd8b306f hwrng: atmel - move set of TRNG_HALFR in atmel_trng_init()
Move set of TRNG_HALFR in atmel_trng_init() as this function is
also called on resume path. In case of SAMA7G5 where backup and
self-refresh PM mode is available most of the SoC parts are
powered of (including TRNG) when entering suspend. In that case
on resuming path TRNG_HALFR should also be re-configured.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:19 +12:00
Claudiu Beznea f14b02088f hwrng: atmel - rename enable/disable functions to init/cleanup
s/atmel_trng_disable/atmel_trng_cleanup/g and
s/atmel_trng_enable/atmel_trng_init/g to cope with
struct hwrng::{init, cleanup} members.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:18 +12:00
Claudiu Beznea a223ea9f89 hwrng: atmel - disable trng on failure path
Call atmel_trng_disable() on failure path of probe.

Fixes: a1fa98d811 ("hwrng: atmel - disable TRNG during suspend")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:18 +12:00
Claudiu Beznea 0934683dd1 hwrng: atmel - add wait for ready support on read
Add wait for ready support on read.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03 10:46:18 +12:00
Joel Stanley f4676c8ec3 ipmi: kcs: aspeed: Remove old bindings support
It's been a few releases since we depreciated the "v1" bindings. Remove
support from the driver as all known device trees have been updated to
use the new bindings.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Message-Id: <20220228062840.449215-1-joel@jms.id.au>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-02-28 10:30:14 -06:00
Jason A. Donenfeld c2a7de4feb random: do crng pre-init loading in worker rather than irq
Taking spinlocks from IRQ context is generally problematic for
PREEMPT_RT. That is, in part, why we take trylocks instead. However, a
spin_try_lock() is also problematic since another spin_lock() invocation
can potentially PI-boost the wrong task, as the spin_try_lock() is
invoked from an IRQ-context, so the task on CPU (random task or idle) is
not the actual owner.

Additionally, by deferring the crng pre-init loading to the worker, we
can use the cryptographic hash function rather than xor, which is
perhaps a meaningful difference when considering this data has only been
through the relatively weak fast_mix() function.

The biggest downside of this approach is that the pre-init loading is
now deferred until later, which means things that need random numbers
after interrupts are enabled, but before workqueues are running -- or
before this particular worker manages to run -- are going to get into
trouble. Hopefully in the real world, this window is rather small,
especially since this code won't run until 64 interrupts had occurred.

Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-28 16:05:25 +01:00
Jason A. Donenfeld abded93ec1 random: unify cycles_t and jiffies usage and types
random_get_entropy() returns a cycles_t, not an unsigned long, which is
sometimes 64 bits on various 32-bit platforms, including x86.
Conversely, jiffies is always unsigned long. This commit fixes things to
use cycles_t for fields that use random_get_entropy(), named "cycles",
and unsigned long for fields that use jiffies, named "now". It's also
good to mix in a cycles_t and a jiffies in the same way for both
add_device_randomness and add_timer_randomness, rather than using xor in
one case. Finally, we unify the order of these volatile reads, always
reading the more precise cycles counter, and then jiffies, so that the
cycle counter is as close to the event as possible.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-28 16:05:25 +01:00
Jason A. Donenfeld 64276a9939 random: cleanup UUID handling
Rather than hard coding various lengths, we can use the right constants.
Strings should be `char *` while buffers should be `u8 *`. Rather than
have a nonsensical and unused maxlength, just remove it. Finally, use
snprintf instead of sprintf, just out of good hygiene.

As well, remove the old comment about returning a binary UUID via the
binary sysctl syscall. That syscall was removed from the kernel in 5.5,
and actually, the "uuid_strategy" function and related infrastructure
for even serving it via the binary sysctl syscall was removed with
894d249115 ("sysctl drivers: Remove dead binary sysctl support") back
in 2.6.33.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-28 16:05:25 +01:00
Kees Cook e52432e164 tpm: vtpm_proxy: Check length to avoid compiler warning
When building with -Warray-bounds under GCC 11.2, this warning was
emitted:

In function 'memset',
    inlined from 'vtpm_proxy_fops_read' at drivers/char/tpm/tpm_vtpm_proxy.c:102:2:
./include/linux/fortify-string.h:43:33: warning: '__builtin_memset' pointer overflow between offset 164 and size [2147483648, 4294967295]
[-Warray-bounds]
   43 | #define __underlying_memset     __builtin_memset
      |                                 ^

This warning appears to be triggered due to the "count < len"
check in vtpm_proxy_fops_read() splitting the CFG[1], and the compiler
attempting to reason about the possible value range in len compared
to the buffer size.

In order to silence this warning, and to keep this code robust if the
use of proxy_dev->req_len ever changes in the future, explicitly check
the size of len before reaching the memset().

[1] https://lore.kernel.org/lkml/CAG48ez1iTF9KegKJrW5a3WzXgCPZJ73nS2_e5esKJRppdzvv8g@mail.gmail.com

Cc: Peter Huewe <peterhuewe@gmx.de>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-integrity@vger.kernel.org
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Link: https://lore.kernel.org/lkml/4b59d305-6858-1514-751a-37853ad777be@linux.ibm.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220119184354.3367603-1-keescook@chromium.org
2022-02-27 10:58:04 -08:00
Christophe JAILLET ffecba83be agp/intel: Remove usage of the deprecated "pci-dma-compat.h" API
In [1], Christoph Hellwig has proposed to remove the wrappers in
include/linux/pci-dma-compat.h.

Some reasons why this API should be removed have been given by Julia
Lawall in [2].

A coccinelle script has been used to perform the needed transformation.
It can be found in [3].

[1]: https://lore.kernel.org/kernel-janitors/20200421081257.GA131897@infradead.org/
[2]: https://lore.kernel.org/kernel-janitors/alpine.DEB.2.22.394.2007120902170.2424@hadrien/
[3]: https://lore.kernel.org/kernel-janitors/20200716192821.321233-1-christophe.jaillet@wanadoo.fr/

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-02-25 17:19:21 +01:00
Arnd Bergmann 25b67f373b TEE shared memory cleanup for v5.18
- The TEE shared memory pool based on two pools is replaced with a single
   somewhat more capable pool.
 - Replaces tee_shm_alloc() and tee_shm_register() with new functions
   easier to use and maintain.  The TEE subsystem and the TEE drivers are
   updated to use the new functions instead.
 - The TEE based Trusted keys routines are updated to use the new
   simplified functions above.
 - The OP-TEE based rng driver is updated to use the new simplified
   functions above.
 - The TEE_SHM-flags are refactored to better match their usage
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Merge tag 'tee-shm-for-v5.18' of git://git.linaro.org:/people/jens.wiklander/linux-tee into arm/drivers

TEE shared memory cleanup for v5.18

- The TEE shared memory pool based on two pools is replaced with a single
  somewhat more capable pool.
- Replaces tee_shm_alloc() and tee_shm_register() with new functions
  easier to use and maintain.  The TEE subsystem and the TEE drivers are
  updated to use the new functions instead.
- The TEE based Trusted keys routines are updated to use the new
  simplified functions above.
- The OP-TEE based rng driver is updated to use the new simplified
  functions above.
- The TEE_SHM-flags are refactored to better match their usage

* tag 'tee-shm-for-v5.18' of git://git.linaro.org:/people/jens.wiklander/linux-tee:
  tee: refactor TEE_SHM_* flags
  tee: replace tee_shm_register()
  KEYS: trusted: tee: use tee_shm_register_kernel_buf()
  tee: add tee_shm_register_{user,kernel}_buf()
  optee: add optee_pool_op_free_helper()
  tee: replace tee_shm_alloc()
  tee: simplify shm pool handling
  tee: add tee_shm_alloc_user_buf()
  tee: remove unused tee_shm_pool_alloc_res_mem()
  hwrng: optee-rng: use tee_shm_alloc_kernel_buf()
  optee: use driver internal tee_context for some rpc

Link: https://lore.kernel.org/r/20220218184802.GA968155@jade
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25 17:05:11 +01:00
Cai Huoqing aef3125dd6 powerpc/BSR: Make use of the helper macro LIST_HEAD()
Replace "struct list_head head = LIST_HEAD_INIT(head)" with
"LIST_HEAD(head)" to simplify the code.

Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
Link: https://lore.kernel.org/r/20220209032450.37849-1-cai.huoqing@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-25 12:10:15 +01:00
Tom Rix 22f01029cd xilinx_hwicap: cleanup comments
Remove the second 'the'.
Replacements:
was to what
intiate to initiate

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20220215193054.3032955-1-trix@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-25 12:08:57 +01:00
Jason A. Donenfeld a3f9e8910e random: only wake up writers after zap if threshold was passed
The only time that we need to wake up /dev/random writers on
RNDCLEARPOOL/RNDZAPPOOL is when we're changing from a value that is
greater than or equal to POOL_MIN_BITS to zero, because if we're
changing from below POOL_MIN_BITS to zero, the writers are already
unblocked.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-24 16:32:35 +01:00
Jason A. Donenfeld da3951ebdc random: round-robin registers as ulong, not u32
When the interrupt handler does not have a valid cycle counter, it calls
get_reg() to read a register from the irq stack, in round-robin.
Currently it does this assuming that registers are 32-bit. This is
_probably_ the case, and probably all platforms without cycle counters
are in fact 32-bit platforms. But maybe not, and either way, it's not
quite correct. This commit fixes that to deal with `unsigned long`
rather than `u32`.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-24 16:32:26 +01:00
Corey Minyard 00d93611f0 ipmi:ipmb: Add the ability to have a separate slave and master device
A situation has come up where there is a slave-only device for the slave
and a separate master device on the same bug.  Allow a separate slave
device to be registered.

Signed-off-by: Corey Minyard <minyard@acm.org>
2022-02-23 08:16:02 -06:00
Corey Minyard 57c9e3c9a3 ipmi:ipmi_ipmb: Unregister the SMI on remove
Otherwise it will continue to be hooked into the IPMI framework.

Signed-off-by: Corey Minyard <minyard@acm.org>
2022-02-23 07:59:17 -06:00
Joel Stanley 2596f6b93a ipmi: kcs: aspeed: Add AST2600 compatible string
The AST2600 is already described in the bindings, but the driver never
gained a compatible string.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Message-Id: <20220221070351.121905-1-joel@jms.id.au>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2022-02-22 11:08:02 -06:00
Jason A. Donenfeld 3191dd5a11 random: clear fast pool, crng, and batches in cpuhp bring up
For the irq randomness fast pool, rather than having to use expensive
atomics, which were visibly the most expensive thing in the entire irq
handler, simply take care of the extreme edge case of resetting count to
zero in the cpuhp online handler, just after workqueues have been
reenabled. This simplifies the code a bit and lets us use vanilla
variables rather than atomics, and performance should be improved.

As well, very early on when the CPU comes up, while interrupts are still
disabled, we clear out the per-cpu crng and its batches, so that it
always starts with fresh randomness.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:21 +01:00
Jason A. Donenfeld b777c38239 random: pull add_hwgenerator_randomness() declaration into random.h
add_hwgenerator_randomness() is a function implemented and documented
inside of random.c. It is the way that hardware RNGs push data into it.
Therefore, it should be declared in random.h. Otherwise sparse complains
with:

random.c:1137:6: warning: symbol 'add_hwgenerator_randomness' was not declared. Should it be static?

The alternative would be to include hw_random.h into random.c, but that
wouldn't really be good for anything except slowing down compile time.

Cc: Matt Mackall <mpm@selenic.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:21 +01:00
Jason A. Donenfeld 1daf2f3876 random: check for crng_init == 0 in add_device_randomness()
This has no real functional change, as crng_pre_init_inject() (and
before that, crng_slow_init()) always checks for == 0, not >= 2. So
correct the outer unlocked change to reflect that. Before this used
crng_ready(), which was not correct.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:21 +01:00
Jason A. Donenfeld da792c6d5f random: unify early init crng load accounting
crng_fast_load() and crng_slow_load() have different semantics:

- crng_fast_load() xors and accounts with crng_init_cnt.
- crng_slow_load() hashes and doesn't account.

However add_hwgenerator_randomness() can afford to hash (it's called
from a kthread), and it should account. Additionally, ones that can
afford to hash don't need to take a trylock but can take a normal lock.
So, we combine these into one function, crng_pre_init_inject(), which
allows us to control these in a uniform way. This will make it simpler
later to simplify this all down when the time comes for that.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:17 +01:00
Jason A. Donenfeld afba0b80b9 random: do not take pool spinlock at boot
Since rand_initialize() is run while interrupts are still off and
nothing else is running, we don't need to repeatedly take and release
the pool spinlock, especially in the RDSEED loop.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:17 +01:00
Jason A. Donenfeld 58340f8e95 random: defer fast pool mixing to worker
On PREEMPT_RT, it's problematic to take spinlocks from hard irq
handlers. We can fix this by deferring to a workqueue the dumping of
the fast pool into the input pool.

We accomplish this with some careful rules on fast_pool->count:

  - When it's incremented to >= 64, we schedule the work.
  - If the top bit is set, we never schedule the work, even if >= 64.
  - The worker is responsible for setting it back to 0 when it's done.

There are two small issues around using workqueues for this purpose that
we work around.

The first issue is that mix_interrupt_randomness() might be migrated to
another CPU during CPU hotplug. This issue is rectified by checking that
it hasn't been migrated (after disabling irqs). If it has been migrated,
then we set the count to zero, so that when the CPU comes online again,
it can requeue the work. As part of this, we switch to using an
atomic_t, so that the increment in the irq handler doesn't wipe out the
zeroing if the CPU comes back online while this worker is running.

The second issue is that, though relatively minor in effect, we probably
want to make sure we get a consistent view of the pool onto the stack,
in case it's interrupted by an irq while reading. To do this, we don't
reenable irqs until after the copy. There are only 18 instructions
between the cli and sti, so this is a pretty tiny window.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sultan Alsawaf <sultan@kerneltoast.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:17 +01:00
Jason A. Donenfeld 5f75d9f3ba random: rewrite header introductory comment
Now that we've re-documented the various sections, we can remove the
outdated text here and replace it with a high-level overview.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:17 +01:00
Jason A. Donenfeld 0deff3c432 random: group sysctl functions
This pulls all of the sysctl-focused functions into the sixth labeled
section.

No functional changes.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:17 +01:00
Jason A. Donenfeld a6adf8e7a6 random: group userspace read/write functions
This pulls all of the userspace read/write-focused functions into the
fifth labeled section.

No functional changes.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:17 +01:00
Jason A. Donenfeld 92c653cf14 random: group entropy collection functions
This pulls all of the entropy collection-focused functions into the
fourth labeled section.

No functional changes.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:09 +01:00
Jason A. Donenfeld a5ed7cb1a7 random: group entropy extraction functions
This pulls all of the entropy extraction-focused functions into the
third labeled section.

No functional changes.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:09 +01:00
Jason A. Donenfeld 3655adc708 random: group crng functions
This pulls all of the crng-focused functions into the second labeled
section.

No functional changes.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:09 +01:00
Jason A. Donenfeld 5f1bb11200 random: group initialization wait functions
This pulls all of the readiness waiting-focused functions into the first
labeled section.

No functional changes.

Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21 21:14:04 +01:00