X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/a415c8e5f6d283c1b9582b4c52d9deab4f72d672..b17f6176484c929bf7e432cd656826339b47df05:/ppp.c diff --git a/ppp.c b/ppp.c index d48c044..3408d86 100644 --- a/ppp.c +++ b/ppp.c @@ -1,6 +1,6 @@ // L2TPNS PPP Stuff -char const *cvs_id_ppp = "$Id: ppp.c,v 1.45 2005-03-10 03:31:25 bodea Exp $"; +char const *cvs_id_ppp = "$Id: ppp.c,v 1.61 2005-05-13 09:23:00 bodea Exp $"; #include #include @@ -24,6 +24,7 @@ extern time_t time_now; extern configt *config; static void initccp(tunnelidt t, sessionidt s); +static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype); // Process PAP messages void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) @@ -39,14 +40,16 @@ void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { LOG(1, s, t, "Short PAP %u bytes\n", l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Short PAP packet.", 3, 0); + return; } if ((hl = ntohs(*(uint16_t *) (p + 2))) > l) { LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "PAP length mismatch.", 3, 0); + return; } l = hl; @@ -54,7 +57,8 @@ void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { LOG(1, s, t, "Unexpected PAP code %d\n", *p); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Unexpected PAP code.", 3, 0); + return; } { @@ -74,7 +78,7 @@ void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) } LOG(3, s, t, "PAP login %s/%s\n", user, pass); } - if (session[s].ip || !session[s].radius) + if (session[s].ip || !sess_local[s].radius) { // respond now, either no RADIUS available or already authenticated uint8_t b[MAXCONTROL]; @@ -102,11 +106,12 @@ void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) } LOG(3, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK"); tunnelsend(b, 5 + (p - b), t); // send it + sessionshutdown(s, "PAP authentication failed.", 3, 0); } else { // set up RADIUS request - uint16_t r = session[s].radius; + uint16_t r = sess_local[s].radius; // Run PRE_AUTH plugins struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 }; @@ -140,7 +145,7 @@ void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) CSTAT(processchap); LOG_HEX(5, "CHAP", p, l); - r = session[s].radius; + r = sess_local[s].radius; if (!r) { LOG(1, s, t, "Unexpected CHAP message\n"); @@ -152,14 +157,16 @@ void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { LOG(1, s, t, "Short CHAP %u bytes\n", l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Short CHAP packet.", 3, 0); + return; } if ((hl = ntohs(*(uint16_t *) (p + 2))) > l) { LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "CHAP length mismatch.", 3, 0); + return; } l = hl; @@ -167,20 +174,23 @@ void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { LOG(1, s, t, "Unexpected CHAP response code %d\n", *p); STAT(tunnel_rx_errors); + sessionshutdown(s, "CHAP length mismatch.", 3, 0); return; } if (p[1] != radius[r].id) { LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0); + return; } if (l < 5 || p[4] != 16) { LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Bad CHAP response length.", 3, 0); + return; } l -= 5; @@ -189,7 +199,8 @@ void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { LOG(1, s, t, "CHAP user too long %d\n", l - 16); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "CHAP username too long.", 3, 0); + return; } // Run PRE_AUTH plugins @@ -275,8 +286,14 @@ static void dumplcp(uint8_t *p, int l) { int proto = ntohs(*(uint16_t *)(o + 2)); LOG(4, 0, 0, " %s 0x%x (%s)\n", lcp_type(type), proto, - proto == PPPCHAP ? "CHAP" : - proto == PPPPAP ? "PAP" : "UNKNOWN"); + proto == PPPPAP ? "PAP" : "UNSUPPORTED"); + } + else if (length == 5) + { + int proto = ntohs(*(uint16_t *)(o + 2)); + int algo = *(uint8_t *)(o + 4); + LOG(4, 0, 0, " %s 0x%x 0x%x (%s)\n", lcp_type(type), proto, algo, + (proto == PPPCHAP && algo == 5) ? "CHAP MD5" : "UNSUPPORTED"); } else LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length); @@ -337,7 +354,33 @@ void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) if (*p == ConfigAck) { - LOG(3, s, t, "LCP: Discarding ConfigAck\n"); + int x = l - 4; + uint8_t *o = (p + 4); + + LOG(3, s, t, "LCP: ConfigAck (%d bytes)...\n", l); + if (config->debug > 3) dumplcp(p, l); + + while (x > 2) + { + int type = o[0]; + int length = o[1]; + + if (length == 0 || type == 0 || x < length) break; + switch (type) + { + case 3: // Authentication-Protocol + { + int proto = ntohs(*(uint16_t *)(o + 2)); + if (proto == PPPCHAP && *(o + 4) == 5) + sendchap(t, s); + } + + break; + } + x -= length; + o += length; + } + session[s].flags |= SF_LCP_ACKED; } else if (*p == ConfigReq) @@ -387,24 +430,35 @@ void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) *q++ = 6; memset(q, 0, 4); // asyncmap 0 q += 4; - *((uint16_t *) (response + 2)) = htons(q - response); // LCP header length break; case 3: // Authentication-Protocol { int proto = ntohs(*(uint16_t *)(o + 2)); char proto_name[] = "0x0000"; + uint8_t *a; + if (proto == PPPPAP) - break; + { + if (config->radius_authtypes & AUTHPAP) + break; - if (response && *response != ConfigNak) // rej already queued - break; + strcpy(proto_name, "PAP"); + } + else if (proto == PPPCHAP) + { + if (config->radius_authtypes & AUTHCHAP + && *(o + 4) == 5) // MD5 + break; - if (proto == PPPCHAP) strcpy(proto_name, "CHAP"); + } else sprintf(proto_name, "%#4.4x", proto); + if (response && *response != ConfigNak) // rej already queued + break; + LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name); if (!response) @@ -415,16 +469,28 @@ void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) q += 4; } - if ((q - b + length) > sizeof(b)) + a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authprefer); + if (!a) { LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name); break; } - memcpy(q, o, length); - *(uint16_t *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead - q += length; - *((uint16_t *) (response + 2)) = htons(q - response); + q = a; + + if (config->radius_authtypes != config->radius_authprefer) + { + a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authtypes & ~config->radius_authprefer); + if (!a) + { + LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name); + break; + } + + q = a; + } + + break; } break; @@ -455,31 +521,97 @@ void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) memcpy(q, o, length); q += length; - *((uint16_t *) (response + 2)) = htons(q - response); // LCP header length } x -= length; o += length; } - if (!response) + if (response) { - // Send back a ConfigAck - q = response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) return; - *q = ConfigAck; + l = q - response; // LCP packet length + *((uint16_t *) (response + 2)) = htons(l); // update header + } + else + { + // Send packet back as ConfigAck + response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); + if (!response) return; + *response = ConfigAck; } LOG(3, s, t, "Sending %s\n", ppp_lcp_type(*response)); - tunnelsend(b, l + (q - b), t); + tunnelsend(b, l + response - b, t); if (!(session[s].flags & SF_LCP_ACKED)) - initlcp(t, s); + sendlcp(t, s, config->radius_authprefer); } else if (*p == ConfigNak) { - LOG(1, s, t, "Remote end sent a ConfigNak. Ignoring\n"); + int x = l - 4; + uint8_t *o = (p + 4); + int authtype = -1; + + LOG(3, s, t, "LCP: ConfigNak (%d bytes)...\n", l); if (config->debug > 3) dumplcp(p, l); - return ; + + while (x > 2) + { + int type = o[0]; + int length = o[1]; + + if (length == 0 || type == 0 || x < length) break; + switch (type) + { + case 1: // Maximum-Receive-Unit + session[s].mru = ntohs(*(uint16_t *)(o + 2)); + LOG(3, s, t, " Remote requested MRU of %u\n", session[s].mru); + break; + + case 3: // Authentication-Protocol + if (authtype > 0) + break; + + { + int proto = ntohs(*(uint16_t *)(o + 2)); + if (proto == PPPPAP) + { + authtype = config->radius_authtypes & AUTHPAP; + LOG(3, s, t, " Remote requested PAP authentication...%sing\n", + authtype ? "accept" : "reject"); + } + else if (proto == PPPCHAP && *(o + 4) == 5) + { + authtype = config->radius_authtypes & AUTHCHAP; + LOG(3, s, t, " Remote requested CHAP authentication...%sing\n", + authtype ? "accept" : "reject"); + } + else + { + LOG(3, s, t, " Rejecting unsupported authentication %#4x\n", + proto); + } + } + + break; + + default: + LOG(2, s, t, " Remote NAKed LCP type %u?\n", type); + break; + } + x -= length; + o += length; + } + + if (!authtype) + { + sessionshutdown(s, "Unsupported authentication.", 3, 0); + return; + } + + if (authtype == -1) + authtype = config->radius_authprefer; + + sendlcp(t, s, authtype); } else if (*p == TerminateReq) { @@ -488,11 +620,11 @@ void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); if (!q) return; tunnelsend(b, l + (q - b), t); // send it - sessionshutdown(s, "Remote end closed connection."); + sessionshutdown(s, "Remote end closed connection.", 3, 0); } else if (*p == TerminateAck) { - sessionshutdown(s, "Connection closed."); + sessionshutdown(s, "Connection closed.", 3, 0); } else if (*p == ProtocolRej) { @@ -538,7 +670,6 @@ void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { LOG(1, s, t, "Unexpected LCP code %d\n", *p); STAT(tunnel_rx_errors); - return ; } } @@ -588,7 +719,7 @@ void processipcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) if (*p == ConfigAck) { // happy with our IPCP - uint16_t r = session[s].radius; + uint16_t r = sess_local[s].radius; if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden) { if (!r) @@ -1076,11 +1207,11 @@ void processccp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) tunnelsend(b, l + (q - b), t); // send it } -// send a CHAP PP packet +// send a CHAP challenge void sendchap(tunnelidt t, sessionidt s) { uint8_t b[MAXCONTROL]; - uint16_t r = session[s].radius; + uint16_t r = sess_local[s].radius; uint8_t *q; CSTAT(sendchap); @@ -1094,8 +1225,6 @@ void sendchap(tunnelidt t, sessionidt s) LOG(1, s, t, "Send CHAP challenge\n"); - // new challenge - random_data(radius[r].auth, sizeof(radius[r].auth)); radius[r].chap = 1; // CHAP not PAP radius[r].id++; if (radius[r].state != RADIUSCHAP) @@ -1105,7 +1234,7 @@ void sendchap(tunnelidt t, sessionidt s) radius[r].retry = backoff(radius[r].try++); if (radius[r].try > 5) { - sessionshutdown(s, "Timeout CHAP"); + sessionshutdown(s, "CHAP timeout.", 3, 0); STAT(tunnel_tx_errors); return ; } @@ -1114,7 +1243,7 @@ void sendchap(tunnelidt t, sessionidt s) *q = 1; // challenge q[1] = radius[r].id; // ID - q[4] = 16; // length + q[4] = 16; // value size (size of challenge) memcpy(q + 5, radius[r].auth, 16); // challenge strcpy(q + 21, hostname); // our name *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length @@ -1165,27 +1294,64 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, tunnelidt t, sessionid return b; } -// Send initial LCP ConfigReq for PAP, set magic no. -void initlcp(tunnelidt t, sessionidt s) +static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype) { - char b[500], *q; + if ((authtype == AUTHCHAP && size < 5) || size < 4) + return 0; + + *b++ = 3; // Authentication-Protocol + if (authtype == AUTHCHAP) + { + *b++ = 5; // length + *(uint16_t *) b = htons(PPPCHAP); b += 2; + *b++ = 5; // MD5 + } + else if (authtype == AUTHPAP) + { + *b++ = 4; // length + *(uint16_t *) b = htons(PPPPAP); b += 2; + } + else + { + LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype); + } + + return b; +} + +// Send initial LCP ConfigReq for MRU, authentication type and magic no +void sendlcp(tunnelidt t, sessionidt s, int authtype) +{ + char b[500], *q, *l; if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP))) return; - LOG(4, s, t, "Sending LCP ConfigReq for PAP\n"); - *q = ConfigReq; - *(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID - *(uint16_t *)(q + 2) = htons(14); // Length - *(uint8_t *)(q + 4) = 5; - *(uint8_t *)(q + 5) = 6; - *(uint32_t *)(q + 6) = htonl(session[s].magic); - *(uint8_t *)(q + 10) = 3; - *(uint8_t *)(q + 11) = 4; - *(uint16_t *)(q + 12) = htons(PPPPAP); // PAP - - LOG_HEX(5, "PPPLCP", q, 14); - tunnelsend(b, (q - b) + 14, t); + LOG(4, s, t, "Sending LCP ConfigReq for %s\n", + authtype == AUTHCHAP ? "CHAP" : "PAP"); + + if (!session[s].mru) + session[s].mru = DEFAULT_MRU; + + l = q; + *l++ = ConfigReq; + *l++ = (time_now % 255) + 1; // ID + + l += 2; //Save space for length + + *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4) + *(uint16_t *) l = htons(session[s].mru); l += 2; + + l = add_lcp_auth(l, sizeof(b) - (l - b), authtype); + + *l++ = 5; *l++ = 6; // Magic-Number (length 6) + *(uint32_t *) l = htonl(session[s].magic); + l += 4; + + *(uint16_t *)(q + 2) = htons(l - q); // Length + + LOG_HEX(5, "PPPLCP", q, l - q); + tunnelsend(b, (l - b), t); } // Send CCP request for no compression