From: Ziyang Xuan william.xuanziyang@huawei.com
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: <IRQ> ? 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 </IRQ> 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.1633764... Cc: stable@vger.kernel.org Reported-by: syzbot+78bab6958a614b0c80b9@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com Acked-by: Oliver Hartkopp socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- 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)