Subject: CVE-2021-47433: btrfs: fix abort logic in btrfs_replace_file_extents

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

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

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

btrfs: fix abort logic in btrfs_replace_file_extents

Error injection testing uncovered a case where we'd end up with a
corrupt file system with a missing extent in the middle of a file.  This
occurs because the if statement to decide if we should abort is wrong.

The only way we would abort in this case is if we got a ret !=
-EOPNOTSUPP and we called from the file clone code.  However the
prealloc code uses this path too.  Instead we need to abort if there is
an error, and the only error we _don't_ abort on is -EOPNOTSUPP and only
if we came from the clone file code.

The Linux kernel CVE team has assigned CVE-2021-47433 to this issue.

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

	Fixed in 5.10.75 with commit 0e32a2b85c7d
	Fixed in 5.14.14 with commit 0e309e1152fc
	Fixed in 5.15 with commit 4afb912f439c

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-2021-47433
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/btrfs/file.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/0e32a2b85c7d92ece86c17dfef390c5ed79c6378
	https://git.kernel.org/stable/c/0e309e1152fc34ef75991d9d69b165dbf75bf26c
	https://git.kernel.org/stable/c/4afb912f439c4bc4e6a4f3e7547f2e69e354108f