Introduce function btrfs_is_namelen_valid.
The function compares arg @namelen with item boundary then returns value
represents namelen is valid or not.
Signed-off-by: Su Yue <suy.f...@cn.fujitsu.com>
---
fs/btrfs/ctree.h | 2 ++
fs/btrfs/dir-item.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 75 insertions(+)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 643c70d2b2e6..70d8778f849b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3037,6 +3037,8 @@ struct btrfs_dir_item *btrfs_match_dir_item_name(struct
btrfs_fs_info *fs_info,
struct btrfs_path *path,
const char *name,
int name_len);
+bool btrfs_is_namelen_valid(struct extent_buffer *leaf, int slot,
+ unsigned long start, u16 namelen);
/* orphan.c */
int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index c24d615e3d7f..fbda228192ed 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -484,3 +484,76 @@ int verify_dir_item(struct btrfs_fs_info *fs_info,
return 0;
}
+
+bool btrfs_is_namelen_valid(struct extent_buffer *leaf, int slot,
+ unsigned long start, u16 namelen)
+{
+ struct btrfs_fs_info *fs_info = leaf->fs_info;
+ struct btrfs_key key;
+ u32 read_start;
+ u32 read_end;
+ u32 item_start;
+ u32 item_end;
+ u32 size;
+ bool ret = true;
+
+ ASSERT(start > btrfs_leaf_data(leaf));
+
+ read_start = start - btrfs_leaf_data(leaf);
+ read_end = read_start + namelen;
+ item_start = btrfs_item_offset_nr(leaf, slot);
+ item_end = btrfs_item_end_nr(leaf, slot);
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+
+ switch (key.type) {
+ case BTRFS_DIR_ITEM_KEY:
+ case BTRFS_XATTR_ITEM_KEY:
+ case BTRFS_DIR_INDEX_KEY:
+ size = sizeof(struct btrfs_dir_item);
+ break;
+ case BTRFS_INODE_REF_KEY:
+ size = sizeof(struct btrfs_inode_ref);
+ break;
+ case BTRFS_INODE_EXTREF_KEY:
+ size = sizeof(struct btrfs_inode_extref);
+ break;
+ default:
+ size = 0;
+ }
+
+ if (!size) {
+ ret = false;
+ goto out;
+ }
+
+ if (read_start < item_start) {
+ ret = false;
+ goto out;
+ }
+ if (read_end > item_end) {
+ ret = false;
+ goto out;
+ }
+
+ /* there shall be item(s) before name */
+ if (read_start - item_start < size) {
+ ret = false;
+ goto out;
+ }
+
+ /*
+ * This may be the last item in the slot
+ * Or same type item(s) is left between read_end and item_end
+ */
+ if (item_end != read_end &&
+ item_end - read_end < size) {
+ ret = false;
+ goto out;
+ }
+out:
+ if (!ret)
+ btrfs_crit(fs_info, "invalid dir item name len: %u",
+ (unsigned int)namelen);
+ return ret;
+}
--
2.13.0
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