+static void
+chapms2_add_to_response_cache(int id, unsigned char *challenge,
+ unsigned char *response,
+ unsigned char *auth_response)
+{
+ int i = chapms2_response_cache_next_index;
+
+ chapms2_response_cache[i].id = id;
+ memcpy(chapms2_response_cache[i].challenge, challenge, 16);
+ memcpy(chapms2_response_cache[i].response, response,
+ MS_CHAP2_RESPONSE_LEN);
+ memcpy(chapms2_response_cache[i].auth_response,
+ auth_response, MS_AUTH_RESPONSE_LENGTH);
+ chapms2_response_cache_next_index =
+ (i + 1) % CHAPMS2_MAX_RESPONSE_CACHE_SIZE;
+ if (chapms2_response_cache_next_index > chapms2_response_cache_size)
+ chapms2_response_cache_size = chapms2_response_cache_next_index;
+ dbglog("added response cache entry %d", i);
+}
+
+static struct chapms2_response_cache_entry*
+chapms2_find_in_response_cache(int id, unsigned char *challenge,
+ unsigned char *auth_response)
+{
+ int i;
+
+ for (i = 0; i < chapms2_response_cache_size; i++) {
+ if (id == chapms2_response_cache[i].id
+ && (!challenge
+ || memcmp(challenge,
+ chapms2_response_cache[i].challenge,
+ 16) == 0)
+ && (!auth_response
+ || memcmp(auth_response,
+ chapms2_response_cache[i].auth_response,
+ MS_AUTH_RESPONSE_LENGTH) == 0)) {
+ dbglog("response found in cache (entry %d)", i);
+ return &chapms2_response_cache[i];
+ }
+ }
+ return NULL; /* not found */
+}
+
+static void
+chapms2_make_response(unsigned char *response, int id, char *our_name,
+ unsigned char *challenge, char *secret, int secret_len,
+ unsigned char *private)
+{
+ const struct chapms2_response_cache_entry *cache_entry;
+ unsigned char auth_response[MS_AUTH_RESPONSE_LENGTH+1];
+
+ challenge++; /* skip length, should be 16 */
+ *response++ = MS_CHAP2_RESPONSE_LEN;
+ cache_entry = chapms2_find_in_response_cache(id, challenge, NULL);
+ if (cache_entry) {
+ memcpy(response, cache_entry->response, MS_CHAP2_RESPONSE_LEN);
+ return;
+ }
+ ChapMS2(challenge,
+#ifdef DEBUGMPPEKEY
+ mschap2_peer_challenge,
+#else
+ NULL,
+#endif
+ our_name, secret, secret_len, response, auth_response,
+ MS_CHAP2_AUTHENTICATEE);
+ chapms2_add_to_response_cache(id, challenge, response, auth_response);
+}
+
+static int
+chapms2_check_success(int id, unsigned char *msg, int len)
+{
+ if ((len < MS_AUTH_RESPONSE_LENGTH + 2) ||
+ strncmp((char *)msg, "S=", 2) != 0) {
+ /* Packet does not start with "S=" */
+ error("MS-CHAPv2 Success packet is badly formed.");
+ return 0;
+ }
+ msg += 2;
+ len -= 2;
+ if (len < MS_AUTH_RESPONSE_LENGTH
+ || !chapms2_find_in_response_cache(id, NULL /* challenge */, msg)) {
+ /* Authenticator Response did not match expected. */
+ error("MS-CHAPv2 mutual authentication failed.");
+ return 0;
+ }
+ /* Authenticator Response matches. */
+ msg += MS_AUTH_RESPONSE_LENGTH; /* Eat it */
+ len -= MS_AUTH_RESPONSE_LENGTH;
+ if ((len >= 3) && !strncmp((char *)msg, " M=", 3)) {
+ msg += 3; /* Eat the delimiter */
+ } else if ((len >= 2) && !strncmp((char *)msg, "M=", 2)) {
+ msg += 2; /* Eat the delimiter */
+ } else if (len) {
+ /* Packet has extra text which does not begin " M=" */
+ error("MS-CHAPv2 Success packet is badly formed.");
+ return 0;
+ }
+ return 1;
+}
+
+static void
+chapms_handle_failure(unsigned char *inp, int len)
+{
+ int err;
+ char *p, *msg;
+
+ /* We want a null-terminated string for strxxx(). */
+ msg = malloc(len + 1);
+ if (!msg) {
+ notice("Out of memory in chapms_handle_failure");
+ return;
+ }
+ BCOPY(inp, msg, len);
+ msg[len] = 0;
+ p = msg;
+
+ /*
+ * Deal with MS-CHAP formatted failure messages; just print the
+ * M=<message> part (if any). For MS-CHAP we're not really supposed
+ * to use M=<message>, but it shouldn't hurt. See
+ * chapms[2]_verify_response.
+ */
+ if (!strncmp(p, "E=", 2))
+ err = strtol(p+2, NULL, 10); /* Remember the error code. */
+ else
+ goto print_msg; /* Message is badly formatted. */
+
+ if (len && ((p = strstr(p, " M=")) != NULL)) {
+ /* M=<message> field found. */
+ p += 3;
+ } else {
+ /* No M=<message>; use the error code. */
+ switch (err) {
+ case MS_CHAP_ERROR_RESTRICTED_LOGON_HOURS:
+ p = "E=646 Restricted logon hours";
+ break;
+
+ case MS_CHAP_ERROR_ACCT_DISABLED:
+ p = "E=647 Account disabled";
+ break;
+
+ case MS_CHAP_ERROR_PASSWD_EXPIRED:
+ p = "E=648 Password expired";
+ break;
+
+ case MS_CHAP_ERROR_NO_DIALIN_PERMISSION:
+ p = "E=649 No dialin permission";
+ break;
+
+ case MS_CHAP_ERROR_AUTHENTICATION_FAILURE:
+ p = "E=691 Authentication failure";
+ break;
+
+ case MS_CHAP_ERROR_CHANGING_PASSWORD:
+ /* Should never see this, we don't support Change Password. */
+ p = "E=709 Error changing password";
+ break;
+
+ default:
+ free(msg);
+ error("Unknown MS-CHAP authentication failure: %.*v",
+ len, inp);
+ return;
+ }
+ }
+print_msg:
+ if (p != NULL)
+ error("MS-CHAP authentication failed: %v", p);
+ free(msg);
+}
+
+static void
+ChallengeResponse(u_char *challenge,
+ u_char PasswordHash[MD4_SIGNATURE_SIZE],
+ u_char response[24])
+{
+ u_char ZPasswordHash[21];
+
+ BZERO(ZPasswordHash, sizeof(ZPasswordHash));
+ BCOPY(PasswordHash, ZPasswordHash, MD4_SIGNATURE_SIZE);