CVE-2021-47457 Information

Description

In the Linux kernel the following vulnerability has been resolved:

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.

Reference

https://git.kernel.org/stable/c/053bc12df0d6097c1126d0e14fa778a0a8faeb64 https://git.kernel.org/stable/c/a76abedd2be3926d6deba236a935c7f98abf9110 https://git.kernel.org/stable/c/9acf636215a6ce9362fe618e7da4913b8bfe84c8