Linux cryptographic layer development
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From: Kent Yoder <key@linux.vnet.ibm.com>
To: linux-crypto@vger.kernel.org
Subject: [PATCH] crypto: Fix byte counter overflow in SHA-512
Date: Fri, 16 Mar 2012 15:26:28 -0500	[thread overview]
Message-ID: <1331929588.3549.4.camel@key-ThinkPad-W510> (raw)

The current code only increments the upper 64 bits of the SHA-512 byte
counter when the number of bytes hashed happens to hit 2^64 exactly.

This patch increments the upper 64 bits whenever the lower 64 bits
overflows.

Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
---
 crypto/sha512_generic.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/crypto/sha512_generic.c b/crypto/sha512_generic.c
index 107f6f7..dd30f40 100644
--- a/crypto/sha512_generic.c
+++ b/crypto/sha512_generic.c
@@ -174,7 +174,7 @@ sha512_update(struct shash_desc *desc, const u8 *data, unsigned int len)
 	index = sctx->count[0] & 0x7f;
 
 	/* Update number of bytes */
-	if (!(sctx->count[0] += len))
+	if ((sctx->count[0] += len) < len)
 		sctx->count[1]++;
 
         part_len = 128 - index;
-- 
1.7.5.4

             reply	other threads:[~2012-03-16 20:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-16 20:26 Kent Yoder [this message]
2012-04-05 12:36 ` [PATCH] crypto: Fix byte counter overflow in SHA-512 Herbert Xu

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