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]

Link: https://lkml.kernel.org/r/20210929180654.32460-1-vvidic@valentin-vidic.from.hr
Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed