[PATCH 4.7 38/69] btrfs: ensure that file descriptor used with subvol ioctls is a dir
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2016-09-28 09:12:10
Also in:
lkml
4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Mahoney <redacted> 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 <redacted> 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@@ -1634,6 +1634,9 @@ 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;
@@ -1691,6 +1694,9 @@ 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);
@@ -1714,6 +1720,9 @@ 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);
@@ -2358,6 +2367,9 @@ 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);