reiserfs: update reiserfs_xattrs_initialized() condition
authorTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Sun, 21 Mar 2021 14:37:49 +0000 (23:37 +0900)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 30 Mar 2021 21:27:32 +0000 (14:27 -0700)
commit5e46d1b78a03d52306f21f77a4e4a144b6d31486
tree026600fa8503b621e67faac085d5fea26f8ea881
parent6ac86aae89289121db784161fe318819778f7f2a
reiserfs: update reiserfs_xattrs_initialized() condition

syzbot is reporting NULL pointer dereference at reiserfs_security_init()
[1], for commit ab17c4f02156c4f7 ("reiserfs: fixup xattr_root caching")
is assuming that REISERFS_SB(s)->xattr_root != NULL in
reiserfs_xattr_jcreate_nblocks() despite that commit made
REISERFS_SB(sb)->priv_root != NULL && REISERFS_SB(s)->xattr_root == NULL
case possible.

I guess that commit 6cb4aff0a77cc0e6 ("reiserfs: fix oops while creating
privroot with selinux enabled") wanted to check xattr_root != NULL
before reiserfs_xattr_jcreate_nblocks(), for the changelog is talking
about the xattr root.

  The issue is that while creating the privroot during mount
  reiserfs_security_init calls reiserfs_xattr_jcreate_nblocks which
  dereferences the xattr root. The xattr root doesn't exist, so we get
  an oops.

Therefore, update reiserfs_xattrs_initialized() to check both the
privroot and the xattr root.

Link: https://syzkaller.appspot.com/bug?id=8abaedbdeb32c861dc5340544284167dd0e46cde
Reported-and-tested-by: syzbot <syzbot+690cb1e51970435f9775@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 6cb4aff0a77c ("reiserfs: fix oops while creating privroot with selinux enabled")
Acked-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Jan Kara <jack@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/reiserfs/xattr.h