4.9-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
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@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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);