From 3df812627e7d0bf557f3781c3448d42c8fe8313e Mon Sep 17 00:00:00 2001
From: Hyunwoo Kim <v4bel@theori.io>
Date: Sat, 9 Dec 2023 05:05:38 -0500
Subject: [PATCH] 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@theori.io>
Link: https://lore.kernel.org/r/20231209100538.GA407321@v4bel-B760M-AORUS-ELITE-AX
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 6fb158172ddc..fc9ef08788f7 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -1285,9 +1285,11 @@ 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);
}