5.4-stable review patch. If anyone has any objections, please let me know.
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From: Hyunwoo Kim v4bel@theori.io
[ 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 6fb158172ddc2..fc9ef08788f73 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); }