Fuzzed image bko-161821.raw cause btrfs check to get segmentation fault.
The function check_owner_ref attempts to access a non-exist quota tree
when dealing with extent_item [4198400 4096] in the corrupted filesystem.
The function btrfs_new_fs_info always allocate memory for
fs_info->quota_root regardless of whether quota_tree exists or not.
Additionally, the function btrfs_read_fs_root will directly return
fs_info->quota_root if location->objectid == BTRFS_QUOTA_TREE_OBJECTID.
This patch does the following things:
1. Do extra check and return ENOENT if quota tree does not exist in the
function btrfs_read_fs_root.
2. Free useless fs_info->quota_root in the function btrfs_setup_all_roots
to reduce confusion.
3. free_extent_buffer even if check_child_node failed in the function
walk_down_tree.
Signed-off-by: Lu Fengqi <lufq.fnst@xxxxxxxxxxxxxx>
---
cmds-check.c | 1 +
disk-io.c | 13 ++++++++++---
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/cmds-check.c b/cmds-check.c
index 17b7efbf..4c7532d0 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -2185,6 +2185,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
ret = check_child_node(cur, path->slots[*level], next);
if (ret) {
+ free_extent_buffer(next);
err = ret;
goto out;
}
diff --git a/disk-io.c b/disk-io.c
index 985c4a9f..6aa6d98a 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -815,7 +815,8 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
return fs_info->csum_root;
if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
- return fs_info->quota_root;
+ return fs_info->quota_enabled ? fs_info->quota_root :
+ ERR_PTR(-ENOENT);
BUG_ON(location->objectid == BTRFS_TREE_RELOC_OBJECTID ||
location->offset != (u64)-1);
@@ -837,12 +838,14 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
{
+ if (fs_info->quota_root)
+ free(fs_info->quota_root);
+
free(fs_info->tree_root);
free(fs_info->extent_root);
free(fs_info->chunk_root);
free(fs_info->dev_root);
free(fs_info->csum_root);
- free(fs_info->quota_root);
free(fs_info->free_space_root);
free(fs_info->super_copy);
free(fs_info->log_root_tree);
@@ -1057,8 +1060,12 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
ret = find_and_setup_root(root, fs_info, BTRFS_QUOTA_TREE_OBJECTID,
fs_info->quota_root);
- if (ret == 0)
+ if (ret) {
+ free(fs_info->quota_root);
+ fs_info->quota_root = NULL;
+ } else {
fs_info->quota_enabled = 1;
+ }
if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
ret = find_and_setup_root(root, fs_info, BTRFS_FREE_SPACE_TREE_OBJECTID,
--
2.12.2
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