Subject: CVE-2021-47458: ocfs2: mount fails with buffer overflow in strlen

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

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

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

ocfs2: mount fails with buffer overflow in strlen

Starting with kernel 5.11 built with CONFIG_FORTIFY_SOURCE mouting an
ocfs2 filesystem with either o2cb or pcmk cluster stack fails with the
trace below.  Problem seems to be that strings for cluster stack and
cluster name are not guaranteed to be null terminated in the disk
representation, while strlcpy assumes that the source string is always
null terminated.  This causes a read outside of the source string
triggering the buffer overflow detection.

  detected buffer overflow in strlen
  ------------[ cut here ]------------
  kernel BUG at lib/string.c:1149!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 1 PID: 910 Comm: mount.ocfs2 Not tainted 5.14.0-1-amd64 #1
    Debian 5.14.6-2
  RIP: 0010:fortify_panic+0xf/0x11
  ...
  Call Trace:
   ocfs2_initialize_super.isra.0.cold+0xc/0x18 [ocfs2]
   ocfs2_fill_super+0x359/0x19b0 [ocfs2]
   mount_bdev+0x185/0x1b0
   legacy_get_tree+0x27/0x40
   vfs_get_tree+0x25/0xb0
   path_mount+0x454/0xa20
   __x64_sys_mount+0x103/0x140
   do_syscall_64+0x3b/0xc0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

The Linux kernel CVE team has assigned CVE-2021-47458 to this issue.

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

	Fixed in 4.4.290 with commit ac011cb3ff7a
	Fixed in 4.9.288 with commit 4b74ddcc22ee
	Fixed in 4.14.253 with commit 232ed9752510
	Fixed in 4.19.214 with commit 7623b1035ca2
	Fixed in 5.4.156 with commit d3a83576378b
	Fixed in 5.10.76 with commit 93be0eeea14c
	Fixed in 5.14.15 with commit 0e677ea5b739
	Fixed in 5.15 with commit b15fa9224e6e

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-2021-47458
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/ocfs2/super.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/ac011cb3ff7a76b3e0e6e77158ee4ba2f929e1fb
	https://git.kernel.org/stable/c/4b74ddcc22ee6455946e80a9c4808801f8f8561e
	https://git.kernel.org/stable/c/232ed9752510de4436468b653d145565669c8498
	https://git.kernel.org/stable/c/7623b1035ca2d17bde0f6a086ad6844a34648df1
	https://git.kernel.org/stable/c/d3a83576378b4c904f711598dde2c5e881c4295c
	https://git.kernel.org/stable/c/93be0eeea14cf39235e585c8f56df3b3859deaad
	https://git.kernel.org/stable/c/0e677ea5b7396f715a76b6b0ef441430e4c4b57f
	https://git.kernel.org/stable/c/b15fa9224e6e1239414525d8d556d824701849fc