Patch "btrfs: ensure that file descriptor used with subvol ioctls is a dir" has been added to the 4.4-stable tree

Patch "btrfs: ensure that file descriptor used with subvol ioctls is a dir" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    btrfs: ensure that file descriptor used with subvol ioctls is a dir

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     btrfs-ensure-that-file-descriptor-used-with-subvol-ioctls-is-a-dir.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 325c50e3cebb9208009083e841550f98a863bfa0 Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@suse.com>
Date: Wed, 21 Sep 2016 08:31:29 -0400
Subject: btrfs: ensure that file descriptor used with subvol ioctls is a dir

From: Jeff Mahoney <jeffm@suse.com>

commit 325c50e3cebb9208009083e841550f98a863bfa0 upstream.

If the subvol/snapshot create/destroy ioctls are passed a regular file
with execute permissions set, we'll eventually Oops while trying to do
inode->i_op->lookup via lookup_one_len.

This patch ensures that the file descriptor refers to a directory.

Fixes: cb8e70901d (Btrfs: Fix subvolume creation locking rules)
Fixes: 76dda93c6a (Btrfs: add snapshot/subvolume destroy ioctl)
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/btrfs/ioctl.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1619,6 +1619,9 @@ static noinline int btrfs_ioctl_snap_cre
 	int namelen;
 	int ret = 0;
 
+	if (!S_ISDIR(file_inode(file)->i_mode))
+		return -ENOTDIR;
+
 	ret = mnt_want_write_file(file);
 	if (ret)
 		goto out;
@@ -1676,6 +1679,9 @@ static noinline int btrfs_ioctl_snap_cre
 	struct btrfs_ioctl_vol_args *vol_args;
 	int ret;
 
+	if (!S_ISDIR(file_inode(file)->i_mode))
+		return -ENOTDIR;
+
 	vol_args = memdup_user(arg, sizeof(*vol_args));
 	if (IS_ERR(vol_args))
 		return PTR_ERR(vol_args);
@@ -1699,6 +1705,9 @@ static noinline int btrfs_ioctl_snap_cre
 	bool readonly = false;
 	struct btrfs_qgroup_inherit *inherit = NULL;
 
+	if (!S_ISDIR(file_inode(file)->i_mode))
+		return -ENOTDIR;
+
 	vol_args = memdup_user(arg, sizeof(*vol_args));
 	if (IS_ERR(vol_args))
 		return PTR_ERR(vol_args);
@@ -2345,6 +2354,9 @@ static noinline int btrfs_ioctl_snap_des
 	int ret;
 	int err = 0;
 
+	if (!S_ISDIR(dir->i_mode))
+		return -ENOTDIR;
+
 	vol_args = memdup_user(arg, sizeof(*vol_args));
 	if (IS_ERR(vol_args))
 		return PTR_ERR(vol_args);


Patches currently in stable-queue which might be from jeffm@suse.com are

queue-4.4/btrfs-ensure-that-file-descriptor-used-with-subvol-ioctls-is-a-dir.patch
queue-4.4/reiserfs-fix-new_insert_key-may-be-used-uninitialized.patch