From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 26 Mar 2018 00:53:25 +0000 (+0800)
Subject: crypto: ahash - Fix early termination in hash walk
X-Git-Tag: v4.1.52~303
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6e4e9aa776470baf9505a9df5bf4b1c2153aef5d;p=thirdparty%2Fkernel%2Fstable.git

crypto: ahash - Fix early termination in hash walk

[ Upstream commit 900a081f6912a8985dc15380ec912752cb66025a ]

When we have an unaligned SG list entry where there is no leftover
aligned data, the hash walk code will incorrectly return zero as if
the entire SG list has been processed.

This patch fixes it by moving onto the next page instead.

Reported-by: Eli Cooper <elicooper@gmx.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---

diff --git a/crypto/ahash.c b/crypto/ahash.c
index 7006dbfd39bd6..6978ad86e516a 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -91,13 +91,14 @@ int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
 
 	if (nbytes && walk->offset & alignmask && !err) {
 		walk->offset = ALIGN(walk->offset, alignmask + 1);
-		walk->data += walk->offset;
-
 		nbytes = min(nbytes,
 			     ((unsigned int)(PAGE_SIZE)) - walk->offset);
 		walk->entrylen -= nbytes;
 
-		return nbytes;
+		if (nbytes) {
+			walk->data += walk->offset;
+			return nbytes;
+		}
 	}
 
 	if (walk->flags & CRYPTO_ALG_ASYNC)