From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
commit 5e46d1b78a03d52306f21f77a4e4a144b6d31486 upstream.
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 # [1]
Reported-and-tested-by: syzbot <syzbot+690cb1e51970435f9775@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Fixes: 6cb4aff0a77c ("reiserfs: fix oops while creating privroot with selinux enabled")
Acked-by: Jeff Mahoney <jeffm@xxxxxxxx>
Acked-by: Jan Kara <jack@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/reiserfs/xattr.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/reiserfs/xattr.h
+++ b/fs/reiserfs/xattr.h
@@ -43,7 +43,7 @@ void reiserfs_security_free(struct reise
static inline int reiserfs_xattrs_initialized(struct super_block *sb)
{
- return REISERFS_SB(sb)->priv_root != NULL;
+ return REISERFS_SB(sb)->priv_root && REISERFS_SB(sb)->xattr_root;
}
#define xattr_size(size) ((size) + sizeof(struct reiserfs_xattr_header))
