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crypto: lib/sha256 - Use memzero_explicit() for clearing state 

Without the barrier_data() inside memzero_explicit(), the compiler may
optimize away the state-clearing if it can tell that the state is not
used afterwards. At least in lib/crypto/sha256.c:__sha256_final(), the
function can get inlined into sha256(), in which case the memset is
optimized away.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Arvind Sankar 2020-10-25 10:31:14 -04:00 committed by Herbert Xu
parent 383e8a8230
commit 1762818f25
1 changed files with 1 additions and 1 deletions
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2
lib/crypto/sha256.c
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@ -265,7 +265,7 @@ static void __sha256_final(struct sha256_state *sctx, u8 *out, int digest_words)
put_unaligned_be32(sctx->state[i], &dst[i]);
/* Zeroize sensitive information. */
memset(sctx, 0, sizeof(*sctx));
memzero_explicit(sctx, sizeof(*sctx));
}
void sha256_final(struct sha256_state *sctx, u8 *out)