crypto: qat - move temp buffers off the stack
Arnd reports that with Kees's latest VLA patches applied, the HMAC handling in the QAT driver uses a worst case estimate of 160 bytes for the SHA blocksize, allowing the compiler to determine the size of the stack frame at compile time and throw a warning: drivers/crypto/qat/qat_common/qat_algs.c: In function 'qat_alg_do_precomputes': drivers/crypto/qat/qat_common/qat_algs.c:257:1: error: the frame size of 1112 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] Given that this worst case estimate is only 32 bytes larger than the actual block size of SHA-512, the use of a VLA here was hiding the excessive size of the stack frame from the compiler, and so we should try to move these buffers off the stack. So move the ipad/opad buffers and the various SHA state descriptors into the tfm context struct. Since qat_alg_do_precomputes() is only called in the context of a setkey() operation, this should be safe. Using SHA512_BLOCK_SIZE for the size of the ipad/opad buffers allows them to be used by SHA-1/SHA-256 as well. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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