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Open Source and information security mailing list archives
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Date: Mon, 5 Jan 2015 08:35:38 +1100 From: Herbert Xu <herbert@...dor.apana.org.au> To: Giel van Schijndel <me@...tis.eu> Cc: linux-kernel@...r.kernel.org, "David S. Miller" <davem@...emloft.net>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>, "maintainer:X86 ARCHITECTURE..." <x86@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Steve French <sfrench@...ba.org>, Rahul Bedarkar <rahulbedarkar89@...il.com>, Thomas Pugliese <thomas.pugliese@...il.com>, Randy Dunlap <rdunlap@...radead.org>, Julia Lawall <Julia.Lawall@...6.fr>, "open list:CRYPTO API" <linux-crypto@...r.kernel.org>, "open list:CERTIFIED WIRELES..." <linux-usb@...r.kernel.org>, "open list:COMMON INTERNET F..." <linux-cifs@...r.kernel.org>, "moderated list:COMMON INTERNET F..." <samba-technical@...ts.samba.org> Subject: Re: [PATCH] Use memzero_explicit to clear local buffers 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@...dor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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