[PATCH 4.4 44/73] crypto: hash - Fix page length clamping in hash walk

Greg Kroah-Hartman
2016-05-17T01:49:37Z

From: Herbert Xu <herbert@gondor.apana.org.au>

commit 13f4bb78cf6a312bbdec367ba3da044b09bf0e29 upstream.

The crypto hash walk code is broken when supplied with an offset
greater than or equal to PAGE_SIZE. This patch fixes it by adjusting
walk->pg and walk->offset when this happens.

Reported-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
crypto/ahash.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -69,8 +69,9 @@ static int hash_walk_new_entry(struct cr
struct scatterlist *sg;

sg = walk->sg;
- walk->pg = sg_page(sg);
walk->offset = sg->offset;
+ walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
+ walk->offset = offset_in_page(walk->offset);
walk->entrylen = sg->length;

if (walk->entrylen > walk->total)