[PATCH] fix races and leaks in vfs_quota_on() users
* new helper: vfs_quota_on_path(); equivalent of vfs_quota_on() sans the
pathname resolution.
* callers of vfs_quota_on() that do their own pathname resolution and
checks based on it are switched to vfs_quota_on_path(); that way we
avoid the races.
* reiserfs leaked dentry/vfsmount references on several failure exits.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/dquot.c b/fs/dquot.c
index 1346eeb..8ec4d6c 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -1793,6 +1793,21 @@
return ret;
}
+int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
+ struct path *path)
+{
+ int error = security_quota_on(path->dentry);
+ if (error)
+ return error;
+ /* Quota file not on the same filesystem? */
+ if (path->mnt->mnt_sb != sb)
+ error = -EXDEV;
+ else
+ error = vfs_quota_on_inode(path->dentry->d_inode, type,
+ format_id);
+ return error;
+}
+
/* Actual function called from quotactl() */
int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path,
int remount)
@@ -1804,19 +1819,10 @@
return vfs_quota_on_remount(sb, type);
error = path_lookup(path, LOOKUP_FOLLOW, &nd);
- if (error < 0)
- return error;
- error = security_quota_on(nd.path.dentry);
- if (error)
- goto out_path;
- /* Quota file not on the same filesystem? */
- if (nd.path.mnt->mnt_sb != sb)
- error = -EXDEV;
- else
- error = vfs_quota_on_inode(nd.path.dentry->d_inode, type,
- format_id);
-out_path:
- path_put(&nd.path);
+ if (!error) {
+ error = vfs_quota_on_path(sb, type, format_id, &nd.path);
+ path_put(&nd.path);
+ }
return error;
}
@@ -2185,6 +2191,7 @@
EXPORT_SYMBOL(dqstats);
EXPORT_SYMBOL(dq_data_lock);
EXPORT_SYMBOL(vfs_quota_on);
+EXPORT_SYMBOL(vfs_quota_on_path);
EXPORT_SYMBOL(vfs_quota_on_mount);
EXPORT_SYMBOL(vfs_quota_off);
EXPORT_SYMBOL(vfs_quota_sync);
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 8ddced3..f38a5af 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -2810,8 +2810,9 @@
journal_unlock_updates(EXT3_SB(sb)->s_journal);
}
+ err = vfs_quota_on_path(sb, type, format_id, &nd.path);
path_put(&nd.path);
- return vfs_quota_on(sb, type, format_id, path, remount);
+ return err;
}
/* Read data from quotafile - avoid pagecache and such because we cannot afford
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b5479b1..1e69f29 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3352,8 +3352,9 @@
jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
}
+ err = vfs_quota_on_path(sb, type, format_id, &nd.path);
path_put(&nd.path);
- return vfs_quota_on(sb, type, format_id, path, remount);
+ return err;
}
/* Read data from quotafile - avoid pagecache and such because we cannot afford
diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index 879e54d..282a135 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -2076,8 +2076,8 @@
return err;
/* Quotafile not on the same filesystem? */
if (nd.path.mnt->mnt_sb != sb) {
- path_put(&nd.path);
- return -EXDEV;
+ err = -EXDEV;
+ goto out;
}
inode = nd.path.dentry->d_inode;
/* We must not pack tails for quota files on reiserfs for quota IO to work */
@@ -2087,8 +2087,8 @@
reiserfs_warning(sb,
"reiserfs: Unpacking tail of quota file failed"
" (%d). Cannot turn on quotas.", err);
- path_put(&nd.path);
- return -EINVAL;
+ err = -EINVAL;
+ goto out;
}
mark_inode_dirty(inode);
}
@@ -2109,13 +2109,15 @@
/* Just start temporary transaction and finish it */
err = journal_begin(&th, sb, 1);
if (err)
- return err;
+ goto out;
err = journal_end_sync(&th, sb, 1);
if (err)
- return err;
+ goto out;
}
+ err = vfs_quota_on_path(sb, type, format_id, &nd.path);
+out:
path_put(&nd.path);
- return vfs_quota_on(sb, type, format_id, path, 0);
+ return err;
}
/* Read data from quotafile - avoid pagecache and such because we cannot afford
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 742187f..ca6b9b5 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -43,6 +43,8 @@
int vfs_quota_on(struct super_block *sb, int type, int format_id,
char *path, int remount);
+int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
+ struct path *path);
int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
int format_id, int type);
int vfs_quota_off(struct super_block *sb, int type, int remount);