Messages in this thread | | | Date | Mon, 5 Jan 2015 08:35:38 +1100 | From | Herbert Xu <> | Subject | Re: [PATCH] Use memzero_explicit to clear local buffers |
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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.
> 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 <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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