[v2.6.34-stable 212/213] crypto: sha512 - Fix byte counter overflow in SHA-512

[Paul Gortmaker]

From: Kent Yoder <key@xxxxxxxxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 25c3d30c918207556ae1d6e663150ebdf902186b upstream.

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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 crypto/sha512_generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/sha512_generic.c b/crypto/sha512_generic.c
index 9ed9f60316e5..899b2fa24e50 100644
--- a/crypto/sha512_generic.c
+++ b/crypto/sha512_generic.c
@@ -177,7 +177,7 @@ 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;
-- 
1.8.5.2

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