Subject: CVE-2024-36923: fs/9p: fix uninitialized values during inode evict

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

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

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

fs/9p: fix uninitialized values during inode evict

If an iget fails due to not being able to retrieve information
from the server then the inode structure is only partially
initialized.  When the inode gets evicted, references to
uninitialized structures (like fscache cookies) were being
made.

This patch checks for a bad_inode before doing anything other
than clearing the inode from the cache.  Since the inode is
bad, it shouldn't have any state associated with it that needs
to be written back (and there really isn't a way to complete
those anyways).

The Linux kernel CVE team has assigned CVE-2024-36923 to this issue.

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

	Fixed in 6.8.10 with commit 1b4cb6e91f19
	Fixed in 6.9 with commit 6630036b7c22

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-2024-36923
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:
	fs/9p/vfs_inode.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/1b4cb6e91f19b81217ad98142ee53a1ab25893fd
	https://git.kernel.org/stable/c/6630036b7c228f57c7893ee0403e92c2db2cd21d