[RFC/RFT PATCH 06/15] crypto: ahash - fix another early termination in hash walk
From: Eric Biggers <ebiggers@kernel.org>
Date: 2019-01-23 22:54:00
Also in:
lkml, stable
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
From: Eric Biggers <redacted>
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@vger.kernel.org
Signed-off-by: Eric Biggers <redacted>
---
crypto/ahash.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/crypto/ahash.c b/crypto/ahash.c
index ca0d3e281fef..81e2767e2164 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c@@ -86,17 +86,17 @@ static int hash_walk_new_entry(struct crypto_hash_walk *walk) 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; }
@@ -116,7 +116,7 @@ int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err) if (err) return err; - if (nbytes) { + if (walk->entrylen) { walk->offset = 0; walk->pg++; return hash_walk_next(walk);
--
2.20.1.321.g9e740568ce-goog