From e441d54de4fd97dd381f3e73636f5ba51ff4c7d9 Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Mon, 5 Jan 2009 16:57:23 -0500
Subject: [PATCH] Btrfs: add permission checks to the ioctls
Only root can add/remove devices
Only root can defrag subtrees
Only files open for writing can be defragged
Only files open for writing can be the destination for a clone
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
fs/btrfs/ioctl.c | 25 +++++++++++++++++++++++--
fs/btrfs/super.c | 3 +++
2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ab429fe0fa0f5..150784e936e6c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -453,6 +453,9 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
if (root->fs_info->sb->s_flags & MS_RDONLY)
return -EROFS;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
if (!vol_args)
@@ -638,16 +641,24 @@ static int btrfs_ioctl_defrag(struct file *file)
switch (inode->i_mode & S_IFMT) {
case S_IFDIR:
+ if (!capable(CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto out;
+ }
btrfs_defrag_root(root, 0);
btrfs_defrag_root(root->fs_info->extent_root, 0);
break;
case S_IFREG:
+ if (!(file->f_mode & FMODE_WRITE)) {
+ ret = -EINVAL;
+ goto out;
+ }
btrfs_defrag_file(file);
break;
}
-
+out:
mnt_drop_write(file->f_path.mnt);
- return 0;
+ return ret;
}
static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
@@ -655,6 +666,9 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
struct btrfs_ioctl_vol_args *vol_args;
int ret;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
if (!vol_args)
@@ -677,6 +691,9 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
struct btrfs_ioctl_vol_args *vol_args;
int ret;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
if (root->fs_info->sb->s_flags & MS_RDONLY)
return -EROFS;
@@ -726,6 +743,10 @@ static long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
* they don't overlap)?
*/
+ /* the destination must be opened for writing */
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EINVAL;
+
ret = mnt_want_write(file->f_path.mnt);
if (ret)
return ret;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 84c3b66564d0f..3814238d6eba4 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -589,6 +589,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
int ret = 0;
int len;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
vol = kmalloc(sizeof(*vol), GFP_KERNEL);
if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {
ret = -EFAULT;
--
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