| Message ID | 20231209100538.GA407321@v4bel-B760M-AORUS-ELITE-AX (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 810c38a369a0a0ce625b5c12169abce1dd9ccd53 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v4] net/rose: Fix Use-After-Free in rose_ioctl | expand |
Hello: This patch was applied to netdev/net.git (main) by Paolo Abeni <pabeni@redhat.com>: On Sat, 9 Dec 2023 05:05:38 -0500 you wrote: > 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. > > [...] Here is the summary with links: - [v4] net/rose: Fix Use-After-Free in rose_ioctl https://git.kernel.org/netdev/net/c/810c38a369a0 You are awesome, thank you!
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 0cc5a4e19900..ecb91ad4ce63 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -1315,9 +1315,11 @@ 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); }
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> --- v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock. v2 -> v3: Change spin_lock to spin_lock_irq v3 -> v4: Delete old comments --- net/rose/af_rose.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)