Subject: CVE-2024-35916: dma-buf: Fix NULL pointer dereference in sanitycheck()

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

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

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

dma-buf: Fix NULL pointer dereference in sanitycheck()

If due to a memory allocation failure mock_chain() returns NULL, it is
passed to dma_fence_enable_sw_signaling() resulting in NULL pointer
dereference there.

Call dma_fence_enable_sw_signaling() only if mock_chain() succeeds.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

The Linux kernel CVE team has assigned CVE-2024-35916 to this issue.

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

	Issue introduced in 6.1 with commit d62c43a953ce and fixed in 6.1.85 with commit 0336995512cd
	Issue introduced in 6.1 with commit d62c43a953ce and fixed in 6.6.26 with commit 156c226cbbdc
	Issue introduced in 6.1 with commit d62c43a953ce and fixed in 6.8.5 with commit eabf131cba1d
	Issue introduced in 6.1 with commit d62c43a953ce and fixed in 6.9 with commit 2295bd846765

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-2024-35916
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/dma-buf/st-dma-fence-chain.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/0336995512cdab0c65e99e4cdd47c4606debe14e
	https://git.kernel.org/stable/c/156c226cbbdcf5f3bce7b2408a33b59fab7fae2c
	https://git.kernel.org/stable/c/eabf131cba1db12005a68378305f13b9090a7a6b
	https://git.kernel.org/stable/c/2295bd846765c766701e666ed2e4b35396be25e6