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[4.14] crypto: arm64/aes-neonbs - don't access already-freed walk.iv

Message ID 20190517172951.58312-1-ebiggers@kernel.org (mailing list archive)
State Not Applicable
Delegated to: Herbert Xu
Headers show
Series [4.14] crypto: arm64/aes-neonbs - don't access already-freed walk.iv | expand

Commit Message

Eric Biggers May 17, 2019, 5:29 p.m. UTC 
From: Eric Biggers <ebiggers@google.com>

commit 4a8108b70508df0b6c4ffa4a3974dab93dcbe851 upstream.
[Please apply to 4.14-stable.]

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.

xts-aes-neonbs doesn't set an alignmask, so currently it isn't affected
by this despite unconditionally accessing walk.iv.  However this is more
subtle than desired, and unconditionally accessing walk.iv has caused a
real problem in other algorithms.  Thus, update xts-aes-neonbs to start
checking the return value of skcipher_walk_virt().

Fixes: 1abee99eafab ("crypto: arm64/aes - reimplement bit-sliced ARM/NEON implementation for arm64")
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 arch/arm64/crypto/aes-neonbs-glue.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Greg KH May 18, 2019, 6:58 a.m. UTC | #1 
On Fri, May 17, 2019 at 10:29:51AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> commit 4a8108b70508df0b6c4ffa4a3974dab93dcbe851 upstream.
> [Please apply to 4.14-stable.]

Now applied, thanks.

greg k-h
diff mbox series

Patch

diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
index c55d68ccb89f8..52975817fdb66 100644
--- a/arch/arm64/crypto/aes-neonbs-glue.c
+++ b/arch/arm64/crypto/aes-neonbs-glue.c
@@ -307,6 +307,8 @@  static int __xts_crypt(struct skcipher_request *req,
 	int err;
 
 	err = skcipher_walk_virt(&walk, req, true);
+	if (err)
+		return err;
 
 	kernel_neon_begin();