Re: [PATCH] Use memzero_explicit to clear local buffers
From: Herbert Xu <hidden>
Date: 2015-01-04 21:37:22
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linux-cifs, lkml
On Sun, Jan 04, 2015 at 07:05:40PM +0100, Giel van Schijndel wrote:
When leaving a function use memzero_explicit instead of memset(0) to clear locally allocated/owned buffers. memset(0) may be optimized away. All of the affected buffers contain sensitive data, key material or derivatives of one of those two.
Nack.
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/crypto/sha256_ssse3_glue.c b/arch/x86/crypto/sha256_ssse3_glue.c index 8fad72f..b616e63 100644 --- a/arch/x86/crypto/sha256_ssse3_glue.c +++ b/arch/x86/crypto/sha256_ssse3_glue.c@@ -164,7 +164,7 @@ static int sha256_ssse3_final(struct shash_desc *desc, u8 *out) dst[i] = cpu_to_be32(sctx->state[i]); /* Wipe context */ - memset(sctx, 0, sizeof(*sctx)); + memzero_explicit(sctx, sizeof(*sctx));
sctx does not point to stack memory so this is bogus. Only stack memory cleared just before it goes out of scope needs memzero_explicit. Cheers, -- Email: Herbert Xu [off-list ref] Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt