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[3.19.y-ckt,stable] Patch "crypto: algif_hash - Fix race condition in hash_check_key" has been added to the 3.19.y-ckt tree

Message ID 1458838352-27410-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa March 24, 2016, 4:52 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    crypto: algif_hash - Fix race condition in hash_check_key

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

From b4f5f13e5229a68283e13d2c0810e93055968ef4 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 15 Jan 2016 22:01:08 +0800
Subject: crypto: algif_hash - Fix race condition in hash_check_key

commit ad46d7e33219218605ea619e32553daf4f346b9f upstream.

We need to lock the child socket in hash_check_key as otherwise
two simultaneous calls can cause the parent socket to be freed.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 crypto/algif_hash.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--
2.7.0
diff mbox

Patch

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index e76385d..1952e4f 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -255,22 +255,23 @@  static struct proto_ops algif_hash_ops = {

 static int hash_check_key(struct socket *sock)
 {
-	int err;
+	int err = 0;
 	struct sock *psk;
 	struct alg_sock *pask;
 	struct algif_hash_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;

@@ -284,6 +285,8 @@  static int hash_check_key(struct socket *sock)

 unlock:
 	release_sock(psk);
+unlock_child:
+	release_sock(sk);

 	return err;
 }