Subject: CVE-2024-40972: ext4: do not create EA inode under buffer lock

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

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

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

ext4: do not create EA inode under buffer lock

ext4_xattr_set_entry() creates new EA inodes while holding buffer lock
on the external xattr block. This is problematic as it nests all the
allocation locking (which acquires locks on other buffers) under the
buffer lock. This can even deadlock when the filesystem is corrupted and
e.g. quota file is setup to contain xattr block as data block. Move the
allocation of EA inode out of ext4_xattr_set_entry() into the callers.

The Linux kernel CVE team has assigned CVE-2024-40972 to this issue.

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

	Fixed in 6.1.107 with commit 0752e7fb549d
	Fixed in 6.6.47 with commit 737fb7853acd
	Fixed in 6.9.7 with commit 111103907234
	Fixed in 6.10 with commit 0a46ef234756

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-2024-40972
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/ext4/xattr.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/0752e7fb549d90c33b4d4186f11cfd25a556d1dd
	https://git.kernel.org/stable/c/737fb7853acd5bc8984f6f42e4bfba3334be8ae1
	https://git.kernel.org/stable/c/111103907234bffd0a34fba070ad9367de058752
	https://git.kernel.org/stable/c/0a46ef234756dca04623b7591e8ebb3440622f0b