Remove the original version of the VMAC template that had the nonce
hardcoded to 0 and produced a digest with the wrong endianness. I'm
unsure whether this had users or not (there are no explicit in-kernel
references to it), but given that the hardcoded nonce made it wildly
insecure unless a unique key was used for each message, let's try
removing it and see if anyone complains.
Leave the new "vmac64" template that requires the nonce to be explicitly
specified as the first 16 bytes of data and uses the correct endianness
for the digest.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently the VMAC template uses a "nonce" hardcoded to 0, which makes
it insecure unless a unique key is set for every message. Also, the
endianness of the final digest is wrong: the implementation uses little
endian, but the VMAC specification has it as big endian, as do other
VMAC implementations such as the one in Crypto++.
Add a new VMAC template where the nonce is passed as the first 16 bytes
of data (similar to what is done for Poly1305's nonce), and the digest
is big endian. Call it "vmac64", since the old name of simply "vmac"
didn't clarify whether the implementation is of VMAC-64 or of VMAC-128
(which produce 64-bit and 128-bit digests respectively); so we fix the
naming ambiguity too.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
syzbot reported a crash in vmac_final() when multiple threads
concurrently use the same "vmac(aes)" transform through AF_ALG. The bug
is pretty fundamental: the VMAC template doesn't separate per-request
state from per-tfm (per-key) state like the other hash algorithms do,
but rather stores it all in the tfm context. That's wrong.
Also, vmac_final() incorrectly zeroes most of the state including the
derived keys and cached pseudorandom pad. Therefore, only the first
VMAC invocation with a given key calculates the correct digest.
Fix these bugs by splitting the per-tfm state from the per-request state
and using the proper init/update/final sequencing for requests.
Reproducer for the crash:
#include <linux/if_alg.h>
#include <sys/socket.h>
#include <unistd.h>
int main()
{
int fd;
struct sockaddr_alg addr = {
.salg_type = "hash",
.salg_name = "vmac(aes)",
};
char buf[256] = { 0 };
fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
bind(fd, (void *)&addr, sizeof(addr));
setsockopt(fd, SOL_ALG, ALG_SET_KEY, buf, 16);
fork();
fd = accept(fd, NULL, NULL);
for (;;)
write(fd, buf, 256);
}
The immediate cause of the crash is that vmac_ctx_t.partial_size exceeds
VMAC_NHBYTES, causing vmac_final() to memset() a negative length.
Reported-by: syzbot+264bca3a6e8d645550d3@syzkaller.appspotmail.com
Fixes: f1939f7c56 ("crypto: vmac - New hash algorithm for intel_txt support")
Cc: <stable@vger.kernel.org> # v2.6.32+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The VMAC template assumes the block cipher has a 128-bit block size, but
it failed to check for that. Thus it was possible to instantiate it
using a 64-bit block size cipher, e.g. "vmac(cast5)", causing
uninitialized memory to be used.
Add the needed check when instantiating the template.
Fixes: f1939f7c56 ("crypto: vmac - New hash algorithm for intel_txt support")
Cc: <stable@vger.kernel.org> # v2.6.32+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This adds the module loading prefix "crypto-" to the template lookup
as well.
For example, attempting to load 'vfat(blowfish)' via AF_ALG now correctly
includes the "crypto-" prefix at every level, correctly rejecting "vfat":
net-pf-38
algif-hash
crypto-vfat(blowfish)
crypto-vfat(blowfish)-all
crypto-vfat
Reported-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Recently, in commit 13aa93c70e71 ("random: add and use memzero_explicit()
for clearing data"), we have found that GCC may optimize some memset()
cases away when it detects a stack variable is not being used anymore
and going out of scope. This can happen, for example, in cases when we
are clearing out sensitive information such as keying material or any
e.g. intermediate results from crypto computations, etc.
With the help of Coccinelle, we can figure out and fix such occurences
in the crypto subsytem as well. Julia Lawall provided the following
Coccinelle program:
@@
type T;
identifier x;
@@
T x;
... when exists
when any
-memset
+memzero_explicit
(&x,
-0,
...)
... when != x
when strict
@@
type T;
identifier x;
@@
T x[...];
... when exists
when any
-memset
+memzero_explicit
(x,
-0,
...)
... when != x
when strict
Therefore, make use of the drop-in replacement memzero_explicit() for
exactly such cases instead of using memset().
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
VMAC implementation, as it is, does not work with blocks that
are not multiples of 128-bytes. Furthermore, this is a problem
when using the implementation on scatterlists, even
when the complete plain text is 128-byte multiple, as the pieces
that get passed to vmac_update can be pretty much any size.
I also added test cases for unaligned blocks.
Signed-off-by: Salman Qazi <sqazi@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fix "symbol 'x' was not declared. Should it be static?" sparse warnings.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Part of the include cleanups means that the implicit
inclusion of module.h via device.h is going away. So
fix things up in advance.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
This patch is to fix the vmac algorithm, add more test cases for vmac,
and fix the test failure on some big endian system like s390.
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds VMAC (a fast MAC) support into crypto framework.
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Joseph Cihula <joseph.cihula@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers
Kees Cook
Daniel Borkmann
Salman Qazi
Jussi Kivilinna
Paul Gortmaker
Lucas De Marchi
Shane Wang