Patch "crypto: algif_aead - fix reference counting of null skcipher" has been added to the 4.14-stable tree

Patch "crypto: algif_aead - fix reference counting of null skcipher" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    crypto: algif_aead - fix reference counting of null skcipher

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-algif_aead-fix-reference-counting-of-null-skcipher.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b32a7dc8aef1882fbf983eb354837488cc9d54dc Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Mon, 27 Nov 2017 23:23:05 -0800
Subject: crypto: algif_aead - fix reference counting of null skcipher

From: Eric Biggers <ebiggers@google.com>

commit b32a7dc8aef1882fbf983eb354837488cc9d54dc upstream.

In the AEAD interface for AF_ALG, the reference to the "null skcipher"
held by each tfm was being dropped in the wrong place -- when each
af_alg_ctx was freed instead of when the aead_tfm was freed.  As
discovered by syzkaller, a specially crafted program could use this to
cause the null skcipher to be freed while it is still in use.

Fix it by dropping the reference in the right place.

Fixes: 72548b093ee3 ("crypto: algif_aead - copy AAD from src to dst")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 crypto/algif_aead.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -503,6 +503,7 @@ static void aead_release(void *private)
 	struct aead_tfm *tfm = private;
 
 	crypto_free_aead(tfm->aead);
+	crypto_put_default_null_skcipher2();
 	kfree(tfm);
 }
 
@@ -535,7 +536,6 @@ static void aead_sock_destruct(struct so
 	unsigned int ivlen = crypto_aead_ivsize(tfm);
 
 	af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
-	crypto_put_default_null_skcipher2();
 	sock_kzfree_s(sk, ctx->iv, ivlen);
 	sock_kfree_s(sk, ctx, ctx->len);
 	af_alg_release_parent(sk);


Patches currently in stable-queue which might be from ebiggers@google.com are

queue-4.14/crypto-algif_aead-fix-reference-counting-of-null-skcipher.patch
queue-4.14/crypto-salsa20-fix-blkcipher_walk-api-usage.patch
queue-4.14/crypto-rsa-fix-buffer-overread-when-stripping-leading-zeroes.patch
queue-4.14/crypto-hmac-require-that-the-underlying-hash-algorithm-is-unkeyed.patch
queue-4.14/crypto-af_alg-fix-null-pointer-dereference-in.patch