Although we have qgroup level check in btrfs-progs, it's not enough
since other programe may still call ioctl directly not using
btrfs-progs. For example, systemd.
But it's btrfs-progs to be blame since we don't provide a
full-function(like subvolume create things) btrfs library with enough
check, and only rely on kernel ioctl.
So Add level checks in kernel too.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
fs/btrfs/ctree.h | 6 ++++++
fs/btrfs/qgroup.c | 4 ++++
2 files changed, 10 insertions(+)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0b18070..cbaf1a4 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1056,6 +1056,12 @@ struct btrfs_block_group_item {
__le64 flags;
} __attribute__ ((__packed__));
+#define BTRFS_QGROUP_LEVEL_SHIFT 48
+static inline u64 btrfs_qgroup_level(u64 qgroupid)
+{
+ return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
+}
+
/*
* is subvolume quota turned on?
*/
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 48b60db..523e5b2 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1010,6 +1010,10 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
struct btrfs_qgroup_list *list;
int ret = 0;
+ /* Check the level of src and dst first */
+ if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
+ return -EINVAL;
+
mutex_lock(&fs_info->qgroup_ioctl_lock);
quota_root = fs_info->quota_root;
if (!quota_root) {
--
2.3.0
--
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