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authorEric Biggers <ebiggers@google.com>2019-04-09 23:46:29 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2019-04-18 22:14:58 +0800
commitaec286cd36eacfd797e3d5dab8d5d23c15d1bb5e (patch)
tree2fc6e16572eaea0884bbaaea1135f9bb1de302dd /crypto/lrw.c
parentcrypto: mxs-dcp - remove set but not used variable 'fini' (diff)
downloadlinux-dev-aec286cd36eacfd797e3d5dab8d5d23c15d1bb5e.tar.xz
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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>
Diffstat (limited to '')
-rw-r--r--crypto/lrw.c4
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]);