refactoring acceptSignedPost

libtorrent/src/disk_io_thread.cpp

@@ -1077,51 +1077,8 @@ namespace libtorrent
 
 		if (!m_settings.disable_hash_checks)
         {
-            *hash_ok = false;
-
-            lazy_entry v;
-            int pos;
-            error_code ec;
-            if (lazy_bdecode((char const*)p->blocks[0].buf, (char const*)p->blocks[0].buf
-                + piece_size, v, ec, &pos) == 0) {
-
-                if( v.type() == lazy_entry::dict_t ) {
-                    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() ) {
-#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
-                        }
-                    }
-                }
-            }
+            *hash_ok = acceptSignedPost((char const*)p->blocks[0].buf, piece_size,
+                                        j.storage->info()->name(), j.piece);
 		}
 
         ret = copy_from_piece(const_cast<cached_piece_entry&>(*p), hit, j, l);

libtorrent/src/storage.cpp

@@ -230,51 +230,8 @@ namespace libtorrent
 
         if (ret > 0)
         {
-            *hash_ok = false;
-
-            lazy_entry v;
-            int pos;
-            error_code ec;
-            if (lazy_bdecode((char const*)buf.iov_base, (char const*)buf.iov_base
-                + ret, v, ec, &pos) == 0) {
-
-                if( v.type() == lazy_entry::dict_t ) {
-                    lazy_entry const* post = v.dict_find_dict("userpost");
-                    std::string sig = v.dict_find_string_value("sig_userpost");
-                    std::string username = m_info->name();
-
-                    if( !post || !sig.size() ) {
-#ifdef TORRENT_DEBUG
-                        printf("h_f_s: 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("h_f_s: expected username '%s' got '%s'\n",
-                                   username.c_str(), n.c_str());
-#endif
-                        } else if( k != slot ) {
-#ifdef TORRENT_DEBUG
-                            printf("h_f_s: expected piece '%d' got '%d'\n",
-                                   slot, 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("h_f_s: bad signature\n");
-                            }
-#endif
-                        }
-                    }
-                }
-            }
+            *hash_ok = acceptSignedPost((char const*)buf.iov_base, ret,
+                                        m_info->name(), slot);
         }
 
         if (error()) return 0;

src/twister.cpp

@@ -26,6 +26,8 @@ twister::twister()
 #define TORRENT_DISABLE_GEO_IP
 #include "libtorrent/aux_/session_impl.hpp"
 
+#define DEBUG_ACCEPT_POST 1
+
 using namespace libtorrent;
 static session *ses = NULL;
 
@@ -514,6 +516,59 @@ bool verifySignature(std::string const &strMessage, std::string const &strUserna
     return (pubkeyRec.GetID() == pubkey.GetID());
 }
 
+bool acceptSignedPost(char const *data, int data_size, std::string username, int seq)
+{
+    bool ret = false;
+
+    lazy_entry v;
+    int pos;
+    error_code ec;
+    if (lazy_bdecode(data, data + data_size, v, ec, &pos) == 0) {
+
+        if( v.type() == lazy_entry::dict_t ) {
+            lazy_entry const* post = v.dict_find_dict("userpost");
+            std::string sig = v.dict_find_string_value("sig_userpost");
+
+            if( !post || !sig.size() ) {
+#ifdef DEBUG_ACCEPT_POST
+                printf("acceptSignedPost: 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 DEBUG_ACCEPT_POST
+                    printf("acceptSignedPost: expected username '%s' got '%s'\n",
+                           username.c_str(), n.c_str());
+#endif
+                } else if( k != seq ) {
+#ifdef DEBUG_ACCEPT_POST
+                    printf("acceptSignedPost: expected piece '%d' got '%d'\n",
+                           slot, k);
+#endif
+                } else if( k < 0 || k > nBestHeight * 2 + 10 ) {
+#ifdef DEBUG_ACCEPT_POST
+                    printf("acceptSignedPost: too much posts from user '%s' rejecting post %d\n",
+                           username.c_str(), k);
+#endif
+                } else {
+                    std::pair<char const*, int> postbuf = post->data_section();
+                    ret = verifySignature(
+                            std::string(postbuf.first,postbuf.second),
+                            username, sig);
+#ifdef DEBUG_ACCEPT_POST
+                    if( !ret ) {
+                        printf("acceptSignedPost: bad signature\n");
+                    }
+#endif
+                }
+            }
+        }
+    }
+    return ret;
+}
+
 int getBestHeight()
 {
     return nBestHeight;

src/twister.h

@@ -18,6 +18,8 @@ void stopSessionTorrent();
 std::string createSignature(std::string const &strMessage, std::string const &strUsername);
 bool verifySignature(std::string const &strMessage, std::string const &strUsername, std::string const &strSign);
 
+bool acceptSignedPost(char const *data, int data_size, std::string username, int seq);
+
 int getBestHeight();
 
 #endif // TWISTER_H