From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 13 Dec 2007 16:44:11 +0000 (+0800)
Subject: [CRYPTO] scatterwalk: Handle zero nbytes in scatterwalk_map_and_copy
X-Git-Tag: v2.6.25-rc1~1242^2~18
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=6e050778c5d08a97d5d98f7cb62bc503e872615c;p=linux-2.6-block.git

[CRYPTO] scatterwalk: Handle zero nbytes in scatterwalk_map_and_copy

It's better to return silently than crash and burn when someone feeds us
a zero length.  In particular the null digest algorithm when used as part
of authenc will do that to us.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 297e19d13c4e..9aeeb52004a5 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -105,6 +105,9 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 	struct scatter_walk walk;
 	unsigned int offset = 0;
 
+	if (!nbytes)
+		return;
+
 	for (;;) {
 		scatterwalk_start(&walk, sg);