From 9acf636215a6ce9362fe618e7da4913b8bfe84c8 Mon Sep 17 00:00:00 2001 From: Ziyang Xuan Date: Sat, 9 Oct 2021 15:40:18 +0800 Subject: [PATCH] can: isotp: isotp_sendmsg(): add result check for wait_event_interruptible() Using wait_event_interruptible() to wait for complete transmission, but do not check the result of wait_event_interruptible() which can be interrupted. It will result in TX buffer has multiple accessors and the later process interferes with the previous process. Following is one of the problems reported by syzbot. ============================================================= WARNING: CPU: 0 PID: 0 at net/can/isotp.c:840 isotp_tx_timer_handler+0x2e0/0x4c0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc7+ #68 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:isotp_tx_timer_handler+0x2e0/0x4c0 Call Trace: ? isotp_setsockopt+0x390/0x390 __hrtimer_run_queues+0xb8/0x610 hrtimer_run_softirq+0x91/0xd0 ? rcu_read_lock_sched_held+0x4d/0x80 __do_softirq+0xe8/0x553 irq_exit_rcu+0xf8/0x100 sysvec_apic_timer_interrupt+0x9e/0xc0 asm_sysvec_apic_timer_interrupt+0x12/0x20 Add result check for wait_event_interruptible() in isotp_sendmsg() to avoid multiple accessers for tx buffer. Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Link: https://lore.kernel.org/all/10ca695732c9dd267c76a3c30f37aefe1ff7e32f.1633764159.git.william.xuanziyang@huawei.com Cc: stable@vger.kernel.org Reported-by: syzbot+78bab6958a614b0c80b9@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan Acked-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index caaa532ece94..2ac29c2b2ca6 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -865,7 +865,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) return -EAGAIN; /* wait for complete transmission of current pdu */ - wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + if (err) + return err; } if (!size || size > MAX_MSG_LENGTH) -- 2.39.5