namei: expand nested_symlink() in its only caller (5a460275) · Commits · 戴 / test

fs/namei.c

+23 −38

Original line number	Diff line number	Diff line
		@@ -1612,43 +1612,6 @@ out_err:
		return err;
		}

		/*
		* This limits recursive symlink follows to 8, while
		* limiting consecutive symlinks to 40.
		*
		* Without that kind of total limit, nasty chains of consecutive
		* symlinks can cause almost arbitrarily long lookups.
		*/
		static inline int nested_symlink(struct nameidata *nd)
		{
		int res;

		if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
		path_put_conditional(&nd->link, nd);
		path_put(&nd->path);
		return -ELOOP;
		}
		BUG_ON(nd->depth >= MAX_NESTED_LINKS);

		nd->depth++;
		current->link_count++;

		do {
		struct path link = nd->link;
		void *cookie;

		res = follow_link(&link, nd, &cookie);
		if (res)
		break;
		res = walk_component(nd, LOOKUP_FOLLOW);
		put_link(nd, &link, cookie);
		} while (res > 0);

		current->link_count--;
		nd->depth--;
		return res;
		}

		/*
		* We can do the critical dentry name comparison and hashing
		* operations one word at a time, but we are limited to:
		@@ -1839,7 +1802,29 @@ static int link_path_walk(const char name, struct nameidata nd)
		return err;

		if (err) {
		err = nested_symlink(nd);
		if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
		path_put_conditional(&nd->link, nd);
		path_put(&nd->path);
		return -ELOOP;
		}
		BUG_ON(nd->depth >= MAX_NESTED_LINKS);

		nd->depth++;
		current->link_count++;

		do {
		struct path link = nd->link;
		void *cookie;

		err = follow_link(&link, nd, &cookie);
		if (err)
		break;
		err = walk_component(nd, LOOKUP_FOLLOW);
		put_link(nd, &link, cookie);
		} while (err > 0);

		current->link_count--;
		nd->depth--;
		if (err)
		return err;
		}