[PATCH] reiserfs: fix null ptr deref in reiserfs_xattr_set

[Edward Adam Davis <eadavis@qq.com>]

Before performing any xattr settings, it is necessary to first confirm that both
xattr_root and priv_root are valid.

Reported-and-tested-by: syzbot+74dce9511a59ad67a492@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com
---
 fs/reiserfs/xattr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 998035a6388e..00fd8f747394 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -618,6 +618,9 @@ int reiserfs_xattr_set(struct inode *inode, const char *name,
 	int error, error2;
 	size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
 
+	if (!reiserfs_xattrs_initialized(inode->i_sb))
+		return -EOPNOTSUPP;
+
 	/* Check before we start a transaction and then do nothing. */
 	if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
 		return -EOPNOTSUPP;
-- 
2.43.0