4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit 77568e535af7c4f97eaef1e555bf0af83772456c upstream.
Hash algorithms with an alignmask set, e.g. "xcbc(aes-aesni)" and
"michael_mic", fail the improved hash tests because they sometimes
produce the wrong digest. The bug is that in the case where a
scatterlist element crosses pages, not all the data is actually hashed
because the scatterlist walk terminates too early. This happens because
the 'nbytes' variable in crypto_hash_walk_done() is assigned the number
of bytes remaining in the page, then later interpreted as the number of
bytes remaining in the scatterlist element. Fix it.
Fixes: 900a081f6912 ("crypto: ahash - Fix early termination in hash walk")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
crypto/ahash.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -85,17 +85,17 @@ static int hash_walk_new_entry(struct cr
int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
{
unsigned int alignmask = walk->alignmask;
- unsigned int nbytes = walk->entrylen;
walk->data -= walk->offset;
- if (nbytes && walk->offset & alignmask && !err) {
- walk->offset = ALIGN(walk->offset, alignmask + 1);
- nbytes = min(nbytes,
- ((unsigned int)(PAGE_SIZE)) - walk->offset);
- walk->entrylen -= nbytes;
+ if (walk->entrylen && (walk->offset & alignmask) && !err) {
+ unsigned int nbytes;
+ walk->offset = ALIGN(walk->offset, alignmask + 1);
+ nbytes = min(walk->entrylen,
+ (unsigned int)(PAGE_SIZE - walk->offset));
if (nbytes) {
+ walk->entrylen -= nbytes;
walk->data += walk->offset;
return nbytes;
}
@@ -115,7 +115,7 @@ int crypto_hash_walk_done(struct crypto_
if (err)
return err;
- if (nbytes) {
+ if (walk->entrylen) {
walk->offset = 0;
walk->pg++;
return hash_walk_next(walk);
