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authorAl Viro <viro@zeniv.linux.org.uk>2008-08-01 04:29:18 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2008-08-01 11:25:25 -0400
commit77e69dac3cefacee939cb107ae9cd520a62338e0 (patch)
tree02ddee5ac85ceb632eab2aff994ffbd3233e51eb
parent1b7e190b4764ea3ca1080404dd593eae5230d2b3 (diff)
[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>
-rw-r--r--fs/dquot.c33
-rw-r--r--fs/ext3/super.c3
-rw-r--r--fs/ext4/super.c3
-rw-r--r--fs/reiserfs/super.c16
-rw-r--r--include/linux/quotaops.h2
5 files changed, 35 insertions, 22 deletions
diff --git a/fs/dquot.c b/fs/dquot.c
index 1346eebe74ce..8ec4d6cc7633 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -1793,6 +1793,21 @@ static int vfs_quota_on_remount(struct super_block *sb, int type)
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 @@ int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path,
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(unregister_quota_format);
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 8ddced384674..f38a5afc39a1 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -2810,8 +2810,9 @@ static int ext3_quota_on(struct super_block *sb, int type, int format_id,
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 b5479b1dff14..1e69f29a8c55 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3352,8 +3352,9 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
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 879e54d35c2d..282a13596c70 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -2076,8 +2076,8 @@ static int reiserfs_quota_on(struct super_block *sb, int type, int format_id,
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 @@ static int reiserfs_quota_on(struct super_block *sb, int type, int format_id,
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 @@ static int reiserfs_quota_on(struct super_block *sb, int type, int format_id,
/* 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 742187f7a05c..ca6b9b5c8d52 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -43,6 +43,8 @@ int dquot_mark_dquot_dirty(struct dquot *dquot);
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);