CVE-2020-36780: i2c: sprd: fix reference leak when pm_runtime_get_sync fails

CVE-2020-36780: i2c: sprd: 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: sprd: fix reference leak when pm_runtime_get_sync fails

The PM reference count is not expected to be incremented on
return in sprd_i2c_master_xfer() and sprd_i2c_remove().

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-2020-36780 to this issue.


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

	Issue introduced in 4.14 with commit 8b9ec0719834 and fixed in 5.4.119 with commit 7e1764312440
	Issue introduced in 4.14 with commit 8b9ec0719834 and fixed in 5.10.37 with commit e547640cee79
	Issue introduced in 4.14 with commit 8b9ec0719834 and fixed in 5.11.21 with commit 9223505e938b
	Issue introduced in 4.14 with commit 8b9ec0719834 and fixed in 5.12.4 with commit d3406ab52097
	Issue introduced in 4.14 with commit 8b9ec0719834 and fixed in 5.13 with commit 3a4f32646311

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-2020-36780
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-sprd.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/7e1764312440c5df9dfe6b436035a03673b0c1b9
	https://git.kernel.org/stable/c/e547640cee7981fd751d2c9cde3a61bdb678b755
	https://git.kernel.org/stable/c/9223505e938ba3db5907e058f4209770cff2f2a7
	https://git.kernel.org/stable/c/d3406ab52097328a3bc4cbe124bfd8f6d51fb86f
	https://git.kernel.org/stable/c/3a4f326463117cee3adcb72999ca34a9aaafda93