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reiserfs: NULL pointer deference in open_xa_dir()

PATCH New Sergey Senozhatsky 1 participant 1 message May 30, 2011

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Sergey Senozhatsky

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PATCH 1/1 reiserfs: NULL pointer deference in open_xa_dir()

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Quoted 3 lines

commit cc350c2764a657ee012efd5bd260a6cd5be2f877
reiserfs: remove unnecessary dentry_unhash from rmdir, dir rename Reiserfs does not have problems with references to unlinked directories.

removed dentry_unhash() from rmdir, dir rename functions. That caused
NULL pointer dereference at open_xa_dir+0x3f/01b3

Trace:
?xattr_unlink()
reiserfs_for_each_xattr()
?mutex_lock_nested()
?get_parent_ip()
reiserfs_delete_xattrs()
reiserfs_evict_inode()
[..]

Patch reverts cc350c2764a657ee012efd5bd260a6cd5be2f877. The difference is that reiserfs_rmdir() calls dentry_unhash() only for xattr dirs, since (as commit message states) references to unlinked non-xattrs directories are handled by reiserfs.

Signed-off-by Sergey Senozhatsky <[email protected]>

---

 fs/reiserfs/namei.c |    7 +++++++
 fs/reiserfs/xattr.c |    1 +
 2 files changed, 8 insertions(+), 0 deletions(-)
fs/reiserfs/namei.c +7 -0
index 1186626..3d3cc6c 100644
@@ -831,6 +831,10 @@ static int reiserfs_rmdir(struct inode *dir, struct dentry *dentry)
 	INITIALIZE_PATH(path);
 	struct reiserfs_dir_entry de;
 
+	/* This is the xattr dir, handle specially. */
+	if (S_ISDIR(dentry->d_inode->i_mode))
+		dentry_unhash(dentry);
+
 	/* we will be doing 2 balancings and update 2 stat data, we change quotas
 	 * of the owner of the directory and of the owner of the parent directory.
 	 * The quota structure is possibly deleted only on last iput => outside

@@ -1225,6 +1229,9 @@ static int reiserfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	unsigned long savelink = 1;
 	struct timespec ctime;
 
+	if (new_dentry->d_inode && S_ISDIR(new_dentry->d_inode->i_mode))
+		dentry_unhash(new_dentry);
+
 	/* three balancings: (1) old name removal, (2) new name insertion
 	   and (3) maybe "save" link insertion
 	   stat data updates: (1) old directory,
fs/reiserfs/xattr.c +1 -0
index e8a62f4..50f1abc 100644
@@ -98,6 +98,7 @@ static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
 
 	reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex,
 					I_MUTEX_CHILD, dir->i_sb);
+	dentry_unhash(dentry);
 	error = dir->i_op->rmdir(dir, dentry);
 	if (!error)
 		dentry->d_inode->i_flags |= S_DEAD;