From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> 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=8abaedbdeb32c861dc5340544284167dd0e46cd... # [1] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/reiserfs/xattr.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/reiserfs/xattr.h b/fs/reiserfs/xattr.h index c764352447ba1..81bec2c80b25c 100644 --- a/fs/reiserfs/xattr.h +++ b/fs/reiserfs/xattr.h @@ -43,7 +43,7 @@ void reiserfs_security_free(struct reiserfs_security_handle *sec); 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)) -- 2.25.1