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crypto: ahash - fix another early termination in hash walk 

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: 900a081f69 ("crypto: ahash - Fix early termination in hash walk")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2019-01-31 23:51:41 -08:00 committed by Herbert Xu
parent 3af3496395
commit 77568e535a
1 changed files with 7 additions and 7 deletions
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14
crypto/ahash.c
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@ -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) int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
{ {
unsigned int alignmask = walk->alignmask; unsigned int alignmask = walk->alignmask;
unsigned int nbytes = walk->entrylen;
walk->data -= walk->offset; walk->data -= walk->offset;
if (nbytes && walk->offset & alignmask && !err) { if (walk->entrylen && (walk->offset & alignmask) && !err) {
walk->offset = ALIGN(walk->offset, alignmask + 1); unsigned int nbytes;
nbytes = min(nbytes,
((unsigned int)(PAGE_SIZE)) - walk->offset);
walk->entrylen -= nbytes;
walk->offset = ALIGN(walk->offset, alignmask + 1);
nbytes = min(walk->entrylen,
(unsigned int)(PAGE_SIZE - walk->offset));
if (nbytes) { if (nbytes) {
walk->entrylen -= nbytes;
walk->data += walk->offset; walk->data += walk->offset;
return nbytes; return nbytes;
} }
@ -116,7 +116,7 @@ int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
if (err) if (err)
return err; return err;
if (nbytes) { if (walk->entrylen) {
walk->offset = 0; walk->offset = 0;
walk->pg++; walk->pg++;
return hash_walk_next(walk); return hash_walk_next(walk);