diff options
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index c9284ce6c6e7..1a5d98811f2b 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3932,6 +3932,25 @@ static long _btrfs_ioctl_set_received_subvol(struct file *file, goto out; } + received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid, + BTRFS_UUID_SIZE); + + /* + * Before we attempt to add the new received uuid, check if we have room + * for it in case there's already an item. If the size of the existing + * item plus this root's ID (u64) exceeds the maximum item size, we can + * return here without the need to abort a transaction. If we don't do + * this check, the btrfs_uuid_tree_add() call below would fail with + * -EOVERFLOW and result in a transaction abort. Malicious users could + * exploit this to turn the fs into RO mode. + */ + if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) { + ret = btrfs_uuid_tree_check_overflow(fs_info, sa->uuid, + BTRFS_UUID_KEY_RECEIVED_SUBVOL); + if (ret < 0) + goto out; + } + /* * 1 - root item * 2 - uuid items (received uuid + subvol uuid) @@ -3947,8 +3966,6 @@ static long _btrfs_ioctl_set_received_subvol(struct file *file, sa->rtime.sec = ct.tv_sec; sa->rtime.nsec = ct.tv_nsec; - received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid, - BTRFS_UUID_SIZE); if (received_uuid_changed && !btrfs_is_empty_uuid(root_item->received_uuid)) { ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid, @@ -3970,7 +3987,8 @@ static long _btrfs_ioctl_set_received_subvol(struct file *file, ret = btrfs_update_root(trans, fs_info->tree_root, &root->root_key, &root->root_item); - if (ret < 0) { + if (unlikely(ret < 0)) { + btrfs_abort_transaction(trans, ret); btrfs_end_transaction(trans); goto out; } |