more consistency checks of userpost

libtorrent/src/disk_io_thread.cpp

@@ -1086,14 +1086,39 @@ namespace libtorrent
                 + piece_size, v, ec, &pos) == 0) {
 
                 if( v.type() == lazy_entry::dict_t ) {
-                    lazy_entry const* post = v.dict_find("userpost");
+                    lazy_entry const* post = v.dict_find_dict("userpost");
                     std::string sig = v.dict_find_string_value("sig_userpost");
                     std::string username = j.storage->info()->name();
-                    if( post && sig.size() ) {
+
+                    if( !post || !sig.size() ) {
+#ifdef TORRENT_DEBUG
+                        printf("r_p_f_c_a_h: missing post or signature\n");
+#endif
+                    } else {
+                        std::string n = post->dict_find_string_value("n");
+                        int k = post->dict_find_int_value("k",-1);
+
+                        if( n != username ) {
+#ifdef TORRENT_DEBUG
+                            printf("r_p_f_c_a_h: expected username '%s' got '%s'\n",
+                                   username.c_str(), n.c_str());
+#endif
+                        } else if( k != j.piece ) {
+#ifdef TORRENT_DEBUG
+                            printf("r_p_f_c_a_h: expected piece '%d' got '%d'\n",
+                                   j.piece, k);
+#endif
+                        } else {
                             std::pair<char const*, int> postbuf = post->data_section();
                             *hash_ok = verifySignature(
                                     std::string(postbuf.first,postbuf.second),
                                     username, sig);
+#ifdef TORRENT_DEBUG
+                            if( !(*hash_ok) ) {
+                                printf("r_p_f_c_a_h: bad signature\n");
+                            }
+#endif
+                        }
                     }
                 }
             }