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| author | Eric Biggers <ebiggers@google.com> | 2019-04-09 23:46:29 -0700 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2019-04-18 22:14:58 +0800 |
| commit | aec286cd36eacfd797e3d5dab8d5d23c15d1bb5e (patch) | |
| tree | 2fc6e16572eaea0884bbaaea1135f9bb1de302dd | |
| parent | 11fe71f146ee652a30ffc3c204105c2d81a00d1c (diff) | |
| download | linux-aec286cd36eacfd797e3d5dab8d5d23c15d1bb5e.tar.bz2 | |
crypto: lrw - don't access already-freed walk.iv
If the user-provided IV needs to be aligned to the algorithm's
alignmask, then skcipher_walk_virt() copies the IV into a new aligned
buffer walk.iv. But skcipher_walk_virt() can fail afterwards, and then
if the caller unconditionally accesses walk.iv, it's a use-after-free.
Fix this in the LRW template by checking the return value of
skcipher_walk_virt().
This bug was detected by my patches that improve testmgr to fuzz
algorithms against their generic implementation. When the extra
self-tests were run on a KASAN-enabled kernel, a KASAN use-after-free
splat occured during lrw(aes) testing.
Fixes: c778f96bf347 ("crypto: lrw - Optimize tweak computation")
Cc: <stable@vger.kernel.org> # v4.20+
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| -rw-r--r-- | crypto/lrw.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/crypto/lrw.c b/crypto/lrw.c index 0430ccd08728..b6666c595a68 100644 --- a/crypto/lrw.c +++ b/crypto/lrw.c @@ -162,8 +162,10 @@ static int xor_tweak(struct skcipher_request *req, bool second_pass) } err = skcipher_walk_virt(&w, req, false); - iv = (__be32 *)w.iv; + if (err) + return err; + iv = (__be32 *)w.iv; counter[0] = be32_to_cpu(iv[3]); counter[1] = be32_to_cpu(iv[2]); counter[2] = be32_to_cpu(iv[1]); |