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As it turns out, the AVX2 multibuffer SHA routines are currently
broken [0], in a way that would have likely been noticed if this
code were in wide use. Since the code is too complicated to be
maintained by anyone except the original authors, and since the
performance benefits for real-world use cases are debatable to
begin with, it is better to drop it entirely for the moment.
[0] https://marc.info/?l=linux-crypto-vger&m=153476243825350&w=2
Suggested-by: Eric Biggers <ebiggers@google.com>
Cc: Megha Dey <megha.dey@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The SHA-512 multibuffer code keeps track of the number of blocks pending
in each lane. The minimum of these values is used to identify the next
lane that will be completed. Unused lanes are set to a large number
(0xFFFFFFFF) so that they don't affect this calculation.
However, it was forgotten to set the lengths to this value in the
initial state, where all lanes are unused. As a result it was possible
for sha512_mb_mgr_get_comp_job_avx2() to select an unused lane, causing
a NULL pointer dereference. Specifically this could happen in the case
where ->update() was passed fewer than SHA512_BLOCK_SIZE bytes of data,
so it then called sha_complete_job() without having actually submitted
any blocks to the multi-buffer code. This hit a NULL pointer
dereference if another task happened to have submitted blocks
concurrently to the same CPU and the flush timer had not yet expired.
Fix this by initializing sha512_mb_mgr->lens correctly.
As usual, this bug was found by syzkaller.
Fixes: 45691e2d9b18 ("crypto: sha512-mb - submit/flush routines for AVX2")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch introduces the routines used to submit and flush buffers
belonging to SHA512 crypto jobs to the SHA512 multibuffer algorithm.
It is implemented mostly in assembly optimized with AVX2 instructions.
Signed-off-by: Megha Dey <megha.dey@linux.intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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