When UBSAN is enabled, we get a very large stack frame for
__serpent_setkey, when the register allocator ends up using more registers
than it has, and has to spill temporary values to the stack. The code
was originally optimized for in-order x86-32 CPU implementations using
older compilers, but it now runs into a highly suboptimal case on all
CPU architectures, as seen by this warning:
crypto/serpent_generic.c: In function '__serpent_setkey':
crypto/serpent_generic.c:436:1: error: the frame size of 2720 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
Disabling -fsanitize=alignment would avoid that warning, presumably the
option turns off a optimization step that is required for getting the
register allocation right, but there is no easy way to do that on gcc-7
(gcc-8 introduces a function attribute for this).
I tried to figure out a way to modify the source code instead, and noticed
that the two stages of the setkey() function (keyiter and sbox) each are
fine by themselves, but not when combined into one function. Splitting
out the entire sbox into a separate function also happens to work fine
with all compilers I tried (arm, arm64 and x86).
The setkey function uses a strange way to handle offsets into the key
array, using both negative and positive index values, as well as adjusting
the array pointer back and forth. I have checked that this actually
makes no difference to modern compilers, but I left that untouched
to make the patch easier to review and to keep the code closer to
the reference implementation.
Link: https://patchwork.kernel.org/patch/9189575/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Commit 5d26a105b5 ("crypto: prefix module autoloading with "crypto-"")
changed the automatic module loading when requesting crypto algorithms
to prefix all module requests with "crypto-". This requires all crypto
modules to have a crypto specific module alias even if their file name
would otherwise match the requested crypto algorithm.
Even though commit 5d26a105b5 added those aliases for a vast amount of
modules, it was missing a few. Add the required MODULE_ALIAS_CRYPTO
annotations to those files to make them get loaded automatically, again.
This fixes, e.g., requesting 'ecb(blowfish-generic)', which used to work
with kernels v3.18 and below.
Also change MODULE_ALIAS() lines to MODULE_ALIAS_CRYPTO(). The former
won't work for crypto modules any more.
Fixes: 5d26a105b5 ("crypto: prefix module autoloading with "crypto-"")
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This prefixes all crypto module loading with "crypto-" so we never run
the risk of exposing module auto-loading to userspace via a crypto API,
as demonstrated by Mathias Krause:
https://lkml.org/lkml/2013/3/4/70
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Combine all crypto_alg to be registered and use new crypto_[un]register_algs
functions. This simplifies init/exit code.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that serpent.c has been cleaned from checkpatch warnings,
we can do clean rename.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Arnd Bergmann
Mathias Krause
Kees Cook
Jussi Kivilinna