[4.2.y-ckt stable] Patch "crypto: algif_skcipher - Fix race condition in skcipher_check_key" has been added to the 4.2.y-ckt tree
Kamal Mostafa
kamal at canonical.com
Wed Jan 27 00:12:45 UTC 2016
This is a note to let you know that I have just added a patch titled
crypto: algif_skcipher - Fix race condition in skcipher_check_key
to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue
This patch is scheduled to be released in version 4.2.8-ckt3.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From 1fd55b28cc449e6233d5a981544a49a46352c3e9 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert at gondor.apana.org.au>
Date: Fri, 15 Jan 2016 22:02:20 +0800
Subject: crypto: algif_skcipher - Fix race condition in skcipher_check_key
commit 1822793a523e5d5730b19cc21160ff1717421bc8 upstream.
We need to lock the child socket in skcipher_check_key as otherwise
two simultaneous calls can cause the parent socket to be freed.
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
crypto/algif_skcipher.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 8d4bf6e..74ffe56 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -756,22 +756,23 @@ static struct proto_ops algif_skcipher_ops = {
static int skcipher_check_key(struct socket *sock)
{
- int err;
+ int err = 0;
struct sock *psk;
struct alg_sock *pask;
struct skcipher_tfm *tfm;
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
+ lock_sock(sk);
if (ask->refcnt)
- return 0;
+ goto unlock_child;
psk = ask->parent;
pask = alg_sk(ask->parent);
tfm = pask->private;
err = -ENOKEY;
- lock_sock(psk);
+ lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
if (!tfm->has_key)
goto unlock;
@@ -785,6 +786,8 @@ static int skcipher_check_key(struct socket *sock)
unlock:
release_sock(psk);
+unlock_child:
+ release_sock(sk);
return err;
}
--
1.9.1
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