From 63caa51833e8701248a8a89d83effe96f30e4c80 Mon Sep 17 00:00:00 2001 From: Hyunwoo Kim 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 Link: https://lore.kernel.org/r/20231209100538.GA407321@v4bel-B760M-AORUS-ELITE-AX Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- 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 49dafe9ac72f..4a5c2dc8dd7a 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); }