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authorArvind Sankar <nivedita@alum.mit.edu>2020-10-25 17:31:14 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2020-10-30 09:35:03 +0300
commit1762818f25f3f99c5083caa13d69e5e5aa2e4b6f (patch)
tree09fd538f8085ed4d5f944eaa50eaabb6177fa9e9
parent383e8a823014532ffd81c787ef9009f1c2bd3b79 (diff)
downloadlinux-1762818f25f3f99c5083caa13d69e5e5aa2e4b6f.tar.xz
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>
-rw-r--r--lib/crypto/sha256.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c
index 2321f6cb322f..d43bc39ab05e 100644
--- a/lib/crypto/sha256.c
+++ b/lib/crypto/sha256.c
@@ -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)