Subject: CVE-2021-47456: can: peak_pci: peak_pci_remove(): fix UAF

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

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

can: peak_pci: peak_pci_remove(): fix UAF

When remove the module peek_pci, referencing 'chan' again after
releasing 'dev' will cause UAF.

Fix this by releasing 'dev' later.

The following log reveals it:

[   35.961814 ] BUG: KASAN: use-after-free in peak_pci_remove+0x16f/0x270 [peak_pci]
[   35.963414 ] Read of size 8 at addr ffff888136998ee8 by task modprobe/5537
[   35.965513 ] Call Trace:
[   35.965718 ]  dump_stack_lvl+0xa8/0xd1
[   35.966028 ]  print_address_description+0x87/0x3b0
[   35.966420 ]  kasan_report+0x172/0x1c0
[   35.966725 ]  ? peak_pci_remove+0x16f/0x270 [peak_pci]
[   35.967137 ]  ? trace_irq_enable_rcuidle+0x10/0x170
[   35.967529 ]  ? peak_pci_remove+0x16f/0x270 [peak_pci]
[   35.967945 ]  __asan_report_load8_noabort+0x14/0x20
[   35.968346 ]  peak_pci_remove+0x16f/0x270 [peak_pci]
[   35.968752 ]  pci_device_remove+0xa9/0x250

The Linux kernel CVE team has assigned CVE-2021-47456 to this issue.

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

	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 4.4.290 with commit 1c616528ba4a
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 4.9.288 with commit 447d44cd2f67
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 4.14.253 with commit 34914971bb32
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 4.19.214 with commit adbda14730aa
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 5.4.156 with commit 1248582e47a9
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 5.10.76 with commit 28f28e4bc3a5
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 5.14.15 with commit 0e5afdc2315b
	Issue introduced in 3.4 with commit e6d9c80b7ca1 and fixed in 5.15 with commit 949fe9b35570

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-2021-47456
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:
	drivers/net/can/sja1000/peak_pci.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/1c616528ba4aeb1125a06b407572ab7b56acae38
	https://git.kernel.org/stable/c/447d44cd2f67a20b596ede3ca3cd67086dfd9ca9
	https://git.kernel.org/stable/c/34914971bb3244db4ce2be44e9438a9b30c56250
	https://git.kernel.org/stable/c/adbda14730aacce41c0d3596415aa39ad63eafd9
	https://git.kernel.org/stable/c/1248582e47a9f7ce0ecd156c39fc61f8b6aa3699
	https://git.kernel.org/stable/c/28f28e4bc3a5e0051faa963f10b778ab38c1db69
	https://git.kernel.org/stable/c/0e5afdc2315b0737edcf55bede4ee1640d2d464d
	https://git.kernel.org/stable/c/949fe9b35570361bc6ee2652f89a0561b26eec98