From 1762818f25f3f99c5083caa13d69e5e5aa2e4b6f Mon Sep 17 00:00:00 2001 From: Arvind Sankar Date: Sun, 25 Oct 2020 10:31:14 -0400 Subject: 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 Reviewed-by: Eric Biggers Acked-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- lib/crypto/sha256.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/crypto') 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) -- cgit v1.2.3