queue-4.14/crypto-ahash-fix-another-early-termination-in-hash-walk.patch

   1 From 77568e535af7c4f97eaef1e555bf0af83772456c Mon Sep 17 00:00:00 2001
   2 From: Eric Biggers <ebiggers@google.com>
   3 Date: Thu, 31 Jan 2019 23:51:41 -0800
   4 Subject: crypto: ahash - fix another early termination in hash walk
   5
   6 From: Eric Biggers <ebiggers@google.com>
   7
   8 commit 77568e535af7c4f97eaef1e555bf0af83772456c upstream.
   9
  10 Hash algorithms with an alignmask set, e.g. "xcbc(aes-aesni)" and
  11 "michael_mic", fail the improved hash tests because they sometimes
  12 produce the wrong digest.  The bug is that in the case where a
  13 scatterlist element crosses pages, not all the data is actually hashed
  14 because the scatterlist walk terminates too early.  This happens because
  15 the 'nbytes' variable in crypto_hash_walk_done() is assigned the number
  16 of bytes remaining in the page, then later interpreted as the number of
  17 bytes remaining in the scatterlist element.  Fix it.
  18
  19 Fixes: 900a081f6912 ("crypto: ahash - Fix early termination in hash walk")
  20 Cc: stable@vger.kernel.org
  21 Signed-off-by: Eric Biggers <ebiggers@google.com>
  22 Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
  23 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  24
  25 ---
  26  crypto/ahash.c |   14 +++++++-------
  27  1 file changed, 7 insertions(+), 7 deletions(-)
  28
  29 --- a/crypto/ahash.c
  30 +++ b/crypto/ahash.c
  31 @@ -86,17 +86,17 @@ static int hash_walk_new_entry(struct cr
  32  int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  33  {
  34         unsigned int alignmask = walk->alignmask;
  35 -       unsigned int nbytes = walk->entrylen;
  36
  37         walk->data -= walk->offset;
  38
  39 -       if (nbytes && walk->offset & alignmask && !err) {
  40 -               walk->offset = ALIGN(walk->offset, alignmask + 1);
  41 -               nbytes = min(nbytes,
  42 -                            ((unsigned int)(PAGE_SIZE)) - walk->offset);
  43 -               walk->entrylen -= nbytes;
  44 +       if (walk->entrylen && (walk->offset & alignmask) && !err) {
  45 +               unsigned int nbytes;
  46
  47 +               walk->offset = ALIGN(walk->offset, alignmask + 1);
  48 +               nbytes = min(walk->entrylen,
  49 +                            (unsigned int)(PAGE_SIZE - walk->offset));
  50                 if (nbytes) {
  51 +                       walk->entrylen -= nbytes;
  52                         walk->data += walk->offset;
  53                         return nbytes;
  54                 }
  55 @@ -116,7 +116,7 @@ int crypto_hash_walk_done(struct crypto_
  56         if (err)
  57                 return err;
  58
  59 -       if (nbytes) {
  60 +       if (walk->entrylen) {
  61                 walk->offset = 0;
  62                 walk->pg++;
  63                 return hash_walk_next(walk);