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authorDirk Engling <erdgeist@erdgeist.org>2020-12-05 06:33:43 +0100
committerDirk Engling <erdgeist@erdgeist.org>2020-12-05 06:33:43 +0100
commit179cf4adb4c20f4e2eacbc91af880a9279454eb2 (patch)
treec8eb8d3b0b77ad97f663e3b5bc0f389a9bad3e43 /receiver.cpp
parentc08a84212ecbe380f0548d58255650deda5e0558 (diff)
Prevent IV reuse to protect agains replay attacks
Diffstat (limited to 'receiver.cpp')
-rw-r--r--receiver.cpp11
1 files changed, 10 insertions, 1 deletions
diff --git a/receiver.cpp b/receiver.cpp
index fdeee05..9e622d9 100644
--- a/receiver.cpp
+++ b/receiver.cpp
@@ -16,6 +16,7 @@
16 16
17#include <string> 17#include <string>
18#include <map> 18#include <map>
19#include <set>
19#include <iostream> 20#include <iostream>
20 21
21const unsigned short PORT = 58132; 22const unsigned short PORT = 58132;
@@ -176,6 +177,7 @@ private:
176}; 177};
177 178
178std::map<uint64_t, std::unique_ptr<Session>> g_sessions; 179std::map<uint64_t, std::unique_ptr<Session>> g_sessions;
180std::set<std::string> g_used_ivs;
179 181
180static uint8_t hex2nyble(char c) 182static uint8_t hex2nyble(char c)
181{ 183{
@@ -283,12 +285,19 @@ int main() {
283 if (session == g_sessions.end()) 285 if (session == g_sessions.end())
284 g_sessions[session_id] = std::make_unique<Session>(session_id, rsa_plain_text); 286 g_sessions[session_id] = std::make_unique<Session>(session_id, rsa_plain_text);
285 break; 287 break;
286 case 1: 288 case 1: {
289 std::string sessid_iv(packet + 1, packet + 1 + SESSION_ID_LENGTH + GCM_IV_LENGTH);
290 if (g_used_ivs.find(sessid_iv) != g_used_ivs.end()) {
291 std::cerr << "Error: Session " << std::hex << session_id << " reused IV. Dropping packet" << std::endl;
292 break;
293 }
294 g_used_ivs.insert(sessid_iv);
287 if (session != g_sessions.end()) 295 if (session != g_sessions.end())
288 session->second->write_log(packet + 1 + SESSION_ID_LENGTH, len - 1 - SESSION_ID_LENGTH); 296 session->second->write_log(packet + 1 + SESSION_ID_LENGTH, len - 1 - SESSION_ID_LENGTH);
289 else 297 else
290 std::cerr << "Error: Can't log to unknown session " << std::hex << session_id << std::endl; 298 std::cerr << "Error: Can't log to unknown session " << std::hex << session_id << std::endl;
291 break; 299 break;
300 }
292 default: 301 default:
293 break; 302 break;
294 } 303 }