From: Jeff Mahoney
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)
Cc: #v2.6.29+
Signed-off-by: Jeff Mahoney
---
fs/btrfs/ioctl.c | 12
1 file changed, 12 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b2a2da5..7fd939b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1634,6 +1634,9 @@ static noinline int
btrfs_ioctl_snap_create_transid(struct file *file,
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_create(struct file
*file,
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_create_v2(struct
file *file,
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);
@@ -2357,6 +2366,9 @@ static noinline int btrfs_ioctl_snap_destroy(struct file
*file,
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);
--
2.7.1
--
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