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authorJosef Bacik <josef@toxicpanda.com>2023-12-15 18:01:44 +0300
committerDavid Sterba <dsterba@suse.com>2023-12-16 01:46:51 +0300
commita8892fd71933126ebae3d60aec5918d4dceaae76 (patch)
tree83aab9853117ef3cbfa618fd214c4429b672ef3a /fs
parente85a0adacf170634878fffcbf34b725aff3f49ed (diff)
downloadlinux-a8892fd71933126ebae3d60aec5918d4dceaae76.tar.xz
btrfs: do not allow non subvolume root targets for snapshot
Our btrfs subvolume snapshot <source> <destination> utility enforces that <source> is the root of the subvolume, however this isn't enforced in the kernel. Update the kernel to also enforce this limitation to avoid problems with other users of this ioctl that don't have the appropriate checks in place. Reported-by: Martin Michaelis <code@mgjm.de> CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Neal Gompa <neal@gompa.dev> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ioctl.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2429ae87ad44..f70ee61dfb70 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1290,6 +1290,15 @@ static noinline int __btrfs_ioctl_snap_create(struct file *file,
* are limited to own subvolumes only
*/
ret = -EPERM;
+ } else if (btrfs_ino(BTRFS_I(src_inode)) != BTRFS_FIRST_FREE_OBJECTID) {
+ /*
+ * Snapshots must be made with the src_inode referring
+ * to the subvolume inode, otherwise the permission
+ * checking above is useless because we may have
+ * permission on a lower directory but not the subvol
+ * itself.
+ */
+ ret = -EINVAL;
} else {
ret = btrfs_mksnapshot(&file->f_path, idmap,
name, namelen,