4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hyunwoo Kim <v4bel@xxxxxxxxx>
[ 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>
---
net/rose/af_rose.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
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);
}
--
2.43.0
