Subject: CVE-2021-47457: can: isotp: isotp_sendmsg(): add result check for wait_event_interruptible()

From: Greg Kroah-Hartman <[email-masked]>

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:
 <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.

The Linux kernel CVE team has assigned CVE-2021-47457 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.10 with commit e057dd3fc20f and fixed in 5.10.76 with commit 053bc12df0d6
	Issue introduced in 5.10 with commit e057dd3fc20f and fixed in 5.14.15 with commit a76abedd2be3
	Issue introduced in 5.10 with commit e057dd3fc20f and fixed in 5.15 with commit 9acf636215a6

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-47457
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	net/can/isotp.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/053bc12df0d6097c1126d0e14fa778a0a8faeb64
	https://git.kernel.org/stable/c/a76abedd2be3926d6deba236a935c7f98abf9110
	https://git.kernel.org/stable/c/9acf636215a6ce9362fe618e7da4913b8bfe84c8