CVE-2020-36783: i2c: img-scb: fix reference leak when pm_runtime_get_sync fails

CVE-2020-36783: i2c: img-scb: fix reference leak when pm_runtime_get_sync fails

[Greg Kroah-Hartman]

From: gregkh@kernel.org

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

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

i2c: img-scb: fix reference leak when pm_runtime_get_sync fails

The PM reference count is not expected to be incremented on
return in functions img_i2c_xfer and img_i2c_init.

However, pm_runtime_get_sync will increment the PM reference
count even failed. Forgetting to putting operation will result
in a reference leak here.

Replace it with pm_runtime_resume_and_get to keep usage
counter balanced.

The Linux kernel CVE team has assigned CVE-2020-36783 to this issue.


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

	Issue introduced in 4.15 with commit 93222bd9b966 and fixed in 5.4.119 with commit 4734c4b1d957
	Issue introduced in 4.15 with commit 93222bd9b966 and fixed in 5.10.37 with commit e80ae8bde412
	Issue introduced in 4.15 with commit 93222bd9b966 and fixed in 5.11.21 with commit 96c4a03658d6
	Issue introduced in 4.15 with commit 93222bd9b966 and fixed in 5.12.4 with commit 7ee35cde1e81
	Issue introduced in 4.15 with commit 93222bd9b966 and fixed in 5.13 with commit 223125e37af8

Please see https://www.kernel.org or 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-2020-36783
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/i2c/busses/i2c-img-scb.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/4734c4b1d9573c9d20bbc46cf37dde095ee011b8
	https://git.kernel.org/stable/c/e80ae8bde41266d3b8bf012460b6593851766006
	https://git.kernel.org/stable/c/96c4a03658d661666c360959aa80cdabfe2972ed
	https://git.kernel.org/stable/c/7ee35cde1e810ad6ca589980b9ec2b7b62946a5b
	https://git.kernel.org/stable/c/223125e37af8a641ea4a09747a6a52172fc4b903