| From | Ben Hutchings <> | Date | Mon, 14 Nov 2016 00:14:07 +0000 | Subject | [PATCH 3.2 136/152] btrfs: ensure that file descriptor used with subvol ioctls is a dir |
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3.2.84-rc1 review patch. If anyone has any objections, please let me know.
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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> [bwh: Backported to 3.2: - Open-code file_inode() - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/btrfs/ioctl.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
--- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1302,6 +1302,9 @@ static noinline int btrfs_ioctl_snap_cre int namelen; int ret = 0; + if (!S_ISDIR(file->f_dentry->d_inode->i_mode)) + return -ENOTDIR; + if (root->fs_info->sb->s_flags & MS_RDONLY) return -EROFS; @@ -1350,6 +1353,9 @@ static noinline int btrfs_ioctl_snap_cre struct btrfs_ioctl_vol_args *vol_args; int ret; + if (!S_ISDIR(file->f_dentry->d_inode->i_mode)) + return -ENOTDIR; + vol_args = memdup_user(arg, sizeof(*vol_args)); if (IS_ERR(vol_args)) return PTR_ERR(vol_args); @@ -1372,6 +1378,9 @@ static noinline int btrfs_ioctl_snap_cre u64 *ptr = NULL; bool readonly = false; + if (!S_ISDIR(file->f_dentry->d_inode->i_mode)) + return -ENOTDIR; + vol_args = memdup_user(arg, sizeof(*vol_args)); if (IS_ERR(vol_args)) return PTR_ERR(vol_args); @@ -1848,6 +1857,9 @@ 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);
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