This is a note to let you know that I've just added the patch titled
net/rose: Fix Use-After-Free in rose_ioctl
to the 4.19-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:
net-rose-fix-use-after-free-in-rose_ioctl.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 515502309030830fd5982ba73aec41d64506cd21
Author: Hyunwoo Kim <v4bel@xxxxxxxxx>
Date: Sat Dec 9 05:05:38 2023 -0500
net/rose: Fix Use-After-Free in rose_ioctl
[ Upstream commit 810c38a369a0a0ce625b5c12169abce1dd9ccd53 ]
Because rose_ioctl() accesses sk->sk_receive_queue
without holding a sk->sk_receive_queue.lock, it can
cause a race with rose_accept().
A use-after-free for skb occurs with the following flow.
```
rose_ioctl() -> skb_peek()
rose_accept() -> skb_dequeue() -> kfree_skb()
```
Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Hyunwoo Kim <v4bel@xxxxxxxxx>
Link: https://lore.kernel.org/r/20231209100538.GA407321@v4bel-B760M-AORUS-ELITE-AX
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 4edd127bb8928..d32fb40650a75 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -1308,9 +1308,11 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
case TIOCINQ: {
struct sk_buff *skb;
long amount = 0L;
- /* These two are safe on a single CPU system as only user tasks fiddle here */
+
+ spin_lock_irq(&sk->sk_receive_queue.lock);
if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
amount = skb->len;
+ spin_unlock_irq(&sk->sk_receive_queue.lock);
return put_user(amount, (unsigned int __user *) argp);
}
