Check return value of snprintf().

[tlsproxy/tlsproxy.git] / src / connection.c

diff --git a/src/connection.c b/src/connection.c
index 880087b9fb6a92193ec280bf71e68151fc372ed8..ed8a59411892bb7f89b12642c9482b0f5bb30850 100644 (file)
--- a/src/connection.c
+++ b/src/connection.c
@@ -87,7 +87,7 @@ void handle_connection(int client_socket) {
     char host[MAX_REQUEST_LINE];
     char port[5 + 1];
 
-    int version_minor;
+    int version_minor; /* HTTP/1.x */
     int result;
 
     /* client_x509_cred is used when talking to the client (acting as a TSL
@@ -208,7 +208,7 @@ void handle_connection(int client_socket) {
 
             LOG(LOG_DEBUG, "transferring data");
 
-            /* Proxy data between client and server until one suite is done
+            /* Proxy data between client and server until one side is done
              * (EOF or error). */
             transfer_data(client_socket, server_socket);
 
@@ -222,9 +222,9 @@ void handle_connection(int client_socket) {
         }
     }
 
+    /* Initialize TLS client credentials to talk to the server. */
     result = initialize_tls_session_server(server_socket, &server_session,
                                                           &server_x509_cred);
-    /* Initialize TLS client credentials to talk to the server. */
     if (0 != result) {
         LOG(LOG_WARNING, "initialize_tls_session_server() failed");
         send_forwarding_failure(client_fd);
@@ -250,7 +250,8 @@ void handle_connection(int client_socket) {
     if (0 != verify_tls_connection(server_session, host)) {
         LOG(LOG_ERROR, "server certificate validation failed!");
         /* We send the error message over our TLS connection to the client,
-         * but with an invalid certificate. */
+         * but with an invalid certificate. No data is transfered from/to the
+         * target server. */
         validation_failed = 1;
     }
 
@@ -298,7 +299,7 @@ void handle_connection(int client_socket) {
 
     LOG(LOG_DEBUG, "transferring TLS data");
 
-    /* Proxy data between client and server until one suite is done (EOF or
+    /* Proxy data between client and server until one side is done (EOF or
      * error). */
     transfer_data_tls(client_socket, server_socket,
                       client_session, server_session);
@@ -370,7 +371,16 @@ static int initialize_tls_session_client(int peer_socket,
             hostname);
         return -1;
     }
-    snprintf(path, sizeof(path), PROXY_SERVER_CERT_FORMAT, hostname);
+    result = snprintf(path, sizeof(path), PROXY_SERVER_CERT_FORMAT, hostname);
+    if (result < 0) {
+        LOG_PERROR(LOG_ERROR,
+                   "initialize_tls_session_client(): snprintf failed");
+        return -1;
+    } else if ((size_t)result >= sizeof(path)) {
+        LOG(LOG_ERROR,
+            "initialize_tls_session_client(): snprintf buffer too short");
+        return -1;
+    }
 
     result = gnutls_certificate_allocate_credentials(x509_cred);
     if (GNUTLS_E_SUCCESS != result) {
@@ -386,18 +396,17 @@ gnutls_certificate_allocate_credentials(): %s",
         result = gnutls_certificate_set_x509_trust_file(*x509_cred,
                                                         PROXY_CA_FILE,
                                                         GNUTLS_X509_FMT_PEM);
+        if (0 >= result) {
+            LOG(LOG_ERROR,
+                "initialize_tls_session_client(): can't read CA file: '%s'",
+                PROXY_CA_FILE);
+            gnutls_certificate_free_credentials(*x509_cred);
+            return -1;
+        }
+    }
     /* If the invalid hostname was specified do nothing, we use a self-signed
      * certificate in this case. */
-    } else {
-        result = 1;
-    }
-    if (0 >= result) {
-        LOG(LOG_ERROR,
-            "initialize_tls_session_client(): can't read CA file: '%s'",
-            PROXY_CA_FILE);
-        gnutls_certificate_free_credentials(*x509_cred);
-        return -1;
-    }
+
     /* And certificate for this website and proxy's private key. */
     if (!use_invalid_cert) {
         result = gnutls_certificate_set_x509_key_file(*x509_cred,
@@ -555,15 +564,26 @@ static void tls_send_invalid_cert_message(gnutls_session_t session) {
 #define RESPONSE_ERROR "500 Internal Server Error"
 #define RESPONSE_MSG   "Server certificate validation failed, check logs."
 
+    int result;
     char buffer[sizeof(HTTP_RESPONSE_FORMAT) - 1 /* '\0' */
                                              - 4 * 2 /* four %s */
                 + (sizeof(RESPONSE_ERROR) - 1 /* '\0' */) * 3
                 + sizeof(RESPONSE_MSG)    - 1 /* '\0' */
                 + 1 /* '\0' */];
 
-    snprintf(buffer, sizeof(buffer),
-             HTTP_RESPONSE_FORMAT,
-             RESPONSE_ERROR, RESPONSE_ERROR, RESPONSE_ERROR, RESPONSE_MSG);
+    result = snprintf(buffer, sizeof(buffer),
+                      HTTP_RESPONSE_FORMAT,
+                      RESPONSE_ERROR, RESPONSE_ERROR, RESPONSE_ERROR,
+                      RESPONSE_MSG);
+    if (result < 0) {
+        LOG_PERROR(LOG_ERROR,
+                   "tls_send_invalid_cert_message(): snprintf failed");
+        return;
+    } else if ((size_t)result >= sizeof(buffer)) {
+        LOG(LOG_ERROR,
+            "tls_send_invalid_cert_message(): snprintf buffer too short");
+        return;
+    }
 
     gnutls_record_send(session, buffer, sizeof(buffer) - 1);
                                         /* don't send trailing '\0' */