From: Alexey Dobriyan Subject: [PATCH 1/3] sha512: make it work, undo percpu message schedule Date: Sat, 14 Jan 2012 21:27:37 +0300 Message-ID: <20120114182737.GB4207@p183.telecom.by> References: <20120111000040.GA3801@p183.telecom.by> <20120111003611.GA12257@gondor.apana.org.au> <20120112235514.GA5065@p183.telecom.by> <20120113070813.GA20068@gondor.apana.org.au> <1326450942.2272.20.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1326451301.2272.23.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1326452246.2272.31.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1326458053.3826.4.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20120114182024.GA4207@p183.telecom.by> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-crypto@vger.kernel.org, netdev@vger.kernel.org, ken@codelabs.ch, Steffen Klassert , Eric Dumazet , security@kernel.org To: Herbert Xu Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:44730 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756128Ab2ANS1o (ORCPT ); Sat, 14 Jan 2012 13:27:44 -0500 Content-Disposition: inline In-Reply-To: <20120114182024.GA4207@p183.telecom.by> Sender: linux-crypto-owner@vger.kernel.org List-ID: commit f9e2bca6c22d75a289a349f869701214d63b5060 aka "crypto: sha512 - Move message schedule W[80] to static percpu area" created global message schedule area. If sha512_update will ever be entered twice, hash will be silently calculated incorrectly. Probably the easiest way to notice incorrect hashes being calculated is to run 2 ping floods over AH with hmac(sha512): #!/usr/sbin/setkey -f flush; spdflush; add IP1 IP2 ah 25 -A hmac-sha512 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000025; add IP2 IP1 ah 52 -A hmac-sha512 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000052; spdadd IP1 IP2 any -P out ipsec ah/transport//require; spdadd IP2 IP1 any -P in ipsec ah/transport//require; XfrmInStateProtoError will start ticking with -EBADMSG being returned from ah_input(). This never happens with, say, hmac(sha1). With patch applied (on BOTH sides), XfrmInStateProtoError does not tick with multiple bidirectional ping flood streams like it doesn't tick with SHA-1. After this patch sha512_transform() will start using ~750 bytes of stack on x86_64. This is OK for simple loads, for something more heavy, stack reduction will be done separatedly. Signed-off-by: Alexey Dobriyan Cc: stable@vger.kernel.org --- crypto/sha512_generic.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) --- a/crypto/sha512_generic.c +++ b/crypto/sha512_generic.c @@ -21,8 +21,6 @@ #include #include -static DEFINE_PER_CPU(u64[80], msg_schedule); - static inline u64 Ch(u64 x, u64 y, u64 z) { return z ^ (x & (y ^ z)); @@ -89,7 +87,7 @@ sha512_transform(u64 *state, const u8 *input) u64 a, b, c, d, e, f, g, h, t1, t2; int i; - u64 *W = get_cpu_var(msg_schedule); + u64 W[80]; /* load the input */ for (i = 0; i < 16; i++) @@ -128,8 +126,6 @@ sha512_transform(u64 *state, const u8 *input) /* erase our data */ a = b = c = d = e = f = g = h = t1 = t2 = 0; - memset(W, 0, sizeof(__get_cpu_var(msg_schedule))); - put_cpu_var(msg_schedule); } static int