X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/5e631c6978946b8333bcd49b79ae5d009ba93413..9c1869ccb199bce1b649cd7923e662f9a88e3488:/radius.c?ds=inline diff --git a/radius.c b/radius.c index dd8a3e6..8481561 100644 --- a/radius.c +++ b/radius.c @@ -1,7 +1,5 @@ // L2TPNS Radius Stuff -char const *cvs_id_radius = "$Id: radius.c,v 1.50 2006/04/27 09:53:50 bodea Exp $"; - #include #include #include @@ -13,6 +11,7 @@ char const *cvs_id_radius = "$Id: radius.c,v 1.50 2006/04/27 09:53:50 bodea Exp #include #include #include + #include "md5.h" #include "constants.h" #include "l2tpns.h" @@ -20,6 +19,9 @@ char const *cvs_id_radius = "$Id: radius.c,v 1.50 2006/04/27 09:53:50 bodea Exp #include "util.h" #include "cluster.h" +#include "l2tplac.h" +#include "pppoe.h" + extern radiust *radius; extern sessiont *session; extern tunnelt *tunnel; @@ -45,6 +47,25 @@ static void calc_auth(const void *buf, size_t len, const uint8_t *in, uint8_t *o void initrad(void) { int i; + uint16_t port = 0; + uint16_t min = config->radius_bind_min; + uint16_t max = config->radius_bind_max; + int inc = 1; + struct sockaddr_in addr; + + if (min) + { + port = min; + if (!max) + max = ~0 - 1; + } + else if (max) /* no minimum specified, bind from max down */ + { + port = max; + min = 1; + inc = -1; + } + LOG(3, 0, 0, "Creating %d sockets for RADIUS queries\n", RADIUS_FDS); radfds = calloc(sizeof(int), RADIUS_FDS); for (i = 0; i < RADIUS_FDS; i++) @@ -53,6 +74,27 @@ void initrad(void) radfds[i] = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); flags = fcntl(radfds[i], F_GETFL, 0); fcntl(radfds[i], F_SETFL, flags | O_NONBLOCK); + + if (port) + { + int b; + + memset(&addr, 0, sizeof(addr)); + addr.sin_family = AF_INET; + addr.sin_addr.s_addr = INADDR_ANY; + + do { + addr.sin_port = htons(port); + if ((b = bind(radfds[i], (struct sockaddr *) &addr, sizeof(addr))) < 0) + { + if ((port += inc) < min || port > max) + { + LOG(0, 0, 0, "Can't bind RADIUS socket in range %u-%u\n", min, max); + exit(1); + } + } + } while (b < 0); + } } } @@ -137,7 +179,7 @@ void radiussend(uint16_t r, uint8_t state) return; } - if (state != RADIUSAUTH && !config->radius_accounting) + if (state != RADIUSAUTH && state != RADIUSJUSTAUTH && !config->radius_accounting) { // Radius accounting is turned off radiusclear(r, s); @@ -157,7 +199,7 @@ void radiussend(uint16_t r, uint8_t state) { if (s) { - if (state == RADIUSAUTH) + if (state == RADIUSAUTH || state == RADIUSJUSTAUTH) sessionshutdown(s, "RADIUS timeout.", CDN_ADMIN_DISC, TERM_REAUTHENTICATION_FAILURE); else { @@ -179,6 +221,7 @@ void radiussend(uint16_t r, uint8_t state) switch (state) { case RADIUSAUTH: + case RADIUSJUSTAUTH: b[0] = AccessRequest; // access request break; case RADIUSSTART: @@ -191,6 +234,7 @@ void radiussend(uint16_t r, uint8_t state) } b[1] = r >> RADIUS_SHIFT; // identifier memcpy(b + 4, radius[r].auth, 16); + p = b + 20; if (s) { @@ -199,7 +243,7 @@ void radiussend(uint16_t r, uint8_t state) strcpy((char *) p + 2, session[s].user); p += p[1]; } - if (state == RADIUSAUTH) + if (state == RADIUSAUTH || state == RADIUSJUSTAUTH) { if (radius[r].chap) { @@ -324,12 +368,20 @@ void radiussend(uint16_t r, uint8_t state) } } + if (session[s].classlen) { + *p = 25; // class + p[1] = session[s].classlen + 2; + memcpy(p + 2, session[s].class, session[s].classlen); + p += p[1]; + } + { struct param_radius_account acct = { &tunnel[session[s].tunnel], &session[s], &p }; run_plugins(PLUGIN_RADIUS_ACCOUNT, &acct); } } } + if (s) { *p = 5; // NAS-Port @@ -339,59 +391,70 @@ void radiussend(uint16_t r, uint8_t state) *p = 6; // Service-Type p[1] = 6; - *(uint32_t *) (p + 2) = htonl(2); // Framed-User + *(uint32_t *) (p + 2) = htonl((state == RADIUSJUSTAUTH ? 8 : 2)); // Authenticate only or Framed-User respectevily p += p[1]; *p = 7; // Framed-Protocol - p[1] = 6; - *(uint32_t *) (p + 2) = htonl(1); // PPP + p[1] = htonl((state == RADIUSJUSTAUTH ? 0 : 6)); + *(uint32_t *) (p + 2) = htonl((state == RADIUSJUSTAUTH ? 0 : 1)); // PPP p += p[1]; - } - if (s && session[s].ip) - { - *p = 8; // Framed-IP-Address - p[1] = 6; - *(uint32_t *) (p + 2) = htonl(session[s].ip); - p += p[1]; - } - if (s && session[s].route[0].ip) - { - int r; - for (r = 0; s && r < MAXROUTE && session[s].route[r].ip; r++) + + if (session[s].ip) { - int width = 32; - if (session[s].route[r].mask) + *p = 8; // Framed-IP-Address + p[1] = 6; + *(uint32_t *) (p + 2) = htonl(session[s].ip); + p += p[1]; + } + + if (session[s].route[0].ip) + { + int r; + for (r = 0; s && r < MAXROUTE && session[s].route[r].ip; r++) { - int mask = session[s].route[r].mask; - while (!(mask & 1)) - { - width--; - mask >>= 1; - } + *p = 22; // Framed-Route + p[1] = sprintf((char *) p + 2, "%s/%d %s 1", + fmtaddr(htonl(session[s].route[r].ip), 0), + session[s].route[r].prefixlen, + fmtaddr(htonl(session[s].ip), 1)) + 2; + + p += p[1]; } + } + + if (session[s].session_timeout) + { + *p = 27; // Session-Timeout + p[1] = 6; + *(uint32_t *) (p + 2) = htonl(session[s].session_timeout); + p += p[1]; + } - *p = 22; // Framed-Route - p[1] = sprintf((char *) p + 2, "%s/%d %s 1", - fmtaddr(htonl(session[s].route[r].ip), 0), - width, fmtaddr(htonl(session[s].ip), 1)) + 2; + if (session[s].idle_timeout) + { + *p = 28; // Idle-Timeout + p[1] = 6; + *(uint32_t *) (p + 2) = htonl(session[s].idle_timeout); + p += p[1]; + } + if (*session[s].called) + { + *p = 30; // called + p[1] = strlen(session[s].called) + 2; + strcpy((char *) p + 2, session[s].called); + p += p[1]; + } + + if (*session[s].calling) + { + *p = 31; // calling + p[1] = strlen(session[s].calling) + 2; + strcpy((char *) p + 2, session[s].calling); p += p[1]; } } - if (*session[s].called) - { - *p = 30; // called - p[1] = strlen(session[s].called) + 2; - strcpy((char *) p + 2, session[s].called); - p += p[1]; - } - if (*session[s].calling) - { - *p = 31; // calling - p[1] = strlen(session[s].calling) + 2; - strcpy((char *) p + 2, session[s].calling); - p += p[1]; - } + // NAS-IP-Address *p = 4; p[1] = 6; @@ -400,7 +463,7 @@ void radiussend(uint16_t r, uint8_t state) // All AVpairs added *(uint16_t *) (b + 2) = htons(p - b); - if (state != RADIUSAUTH) + if (state != RADIUSAUTH && state != RADIUSJUSTAUTH) { // Build auth for accounting packet calc_auth(b, p - b, zero, b + 4); @@ -413,7 +476,7 @@ void radiussend(uint16_t r, uint8_t state) // get radius port uint16_t port = config->radiusport[(radius[r].try - 1) % config->numradiusservers]; // assume RADIUS accounting port is the authentication port +1 - addr.sin_port = htons((state == RADIUSAUTH) ? port : port+1); + addr.sin_port = htons((state == RADIUSAUTH || state == RADIUSJUSTAUTH) ? port : port+1); } LOG_HEX(5, "RADIUS Send", b, (p - b)); @@ -472,6 +535,7 @@ void processrad(uint8_t *buf, int len, char socket_index) uint8_t routes = 0; int r_code; int r_id; + int OpentunnelReq = 0; CSTAT(processrad); @@ -496,7 +560,7 @@ void processrad(uint8_t *buf, int len, char socket_index) LOG(1, s, session[s].tunnel, " Unexpected RADIUS response\n"); return; } - if (radius[r].state != RADIUSAUTH && radius[r].state != RADIUSSTART + if (radius[r].state != RADIUSAUTH && radius[r].state != RADIUSJUSTAUTH && radius[r].state != RADIUSSTART && radius[r].state != RADIUSSTOP && radius[r].state != RADIUSINTERIM) { LOG(1, s, session[s].tunnel, " Unexpected RADIUS response\n"); @@ -511,7 +575,7 @@ void processrad(uint8_t *buf, int len, char socket_index) return; // Do nothing. On timeout, it will try the next radius server. } - if ((radius[r].state == RADIUSAUTH && r_code != AccessAccept && r_code != AccessReject) || + if (((radius[r].state == RADIUSAUTH ||radius[r].state == RADIUSJUSTAUTH) && r_code != AccessAccept && r_code != AccessReject) || ((radius[r].state == RADIUSSTART || radius[r].state == RADIUSSTOP || radius[r].state == RADIUSINTERIM) && r_code != AccountingResponse)) { LOG(1, s, session[s].tunnel, " Unexpected RADIUS response %s\n", radius_code(r_code)); @@ -519,7 +583,7 @@ void processrad(uint8_t *buf, int len, char socket_index) // care off finishing the radius session if that's really correct. } - if (radius[r].state == RADIUSAUTH) + if (radius[r].state == RADIUSAUTH || radius[r].state == RADIUSJUSTAUTH) { // run post-auth plugin struct param_post_auth packet = { @@ -533,6 +597,7 @@ void processrad(uint8_t *buf, int len, char socket_index) run_plugins(PLUGIN_POST_AUTH, &packet); r_code = packet.auth_allowed ? AccessAccept : AccessReject; +#ifndef LAC // process auth response if (radius[r].chap) { @@ -564,6 +629,7 @@ void processrad(uint8_t *buf, int len, char socket_index) LOG(3, s, session[s].tunnel, " PAP User %s authentication %s.\n", session[s].user, (r_code == AccessAccept) ? "allowed" : "denied"); } +#endif if (r_code == AccessAccept) { @@ -571,8 +637,41 @@ void processrad(uint8_t *buf, int len, char socket_index) // Extract IP, routes, etc uint8_t *p = buf + 20; uint8_t *e = buf + len; + uint8_t tag; + uint8_t strtemp[256]; + lac_reset_rad_tag_tunnel_ctxt(); + for (; p + 2 <= e && p[1] && p + p[1] <= e; p += p[1]) { + if (*p == 26 && p[1] >= 7) + { + // Vendor-Specific Attribute + uint32_t vendor = ntohl(*(int *)(p + 2)); + uint8_t attrib = *(p + 6); + int attrib_length = *(p + 7) - 2; + + LOG(4, s, session[s].tunnel, " Radius reply contains Vendor-Specific. Vendor=%u Attrib=%u Length=%d\n", vendor, attrib, attrib_length); + if (vendor == 9 && attrib == 1) // Cisco-AVPair + { + if (attrib_length < 0) continue; + LOG(3, s, session[s].tunnel, " Cisco-AVPair value: %.*s\n", + attrib_length, p + 8); + + handle_avpair(s, p + 8, attrib_length); + continue; + } + else if (vendor == 529 && attrib >= 135 && attrib <= 136) // Ascend + { + // handle old-format ascend DNS attributes below + p += 6; + } + else + { + LOG(3, s, session[s].tunnel, " Unknown vendor-specific\n"); + continue; + } + } + if (*p == 8) { // Framed-IP-Address @@ -593,19 +692,6 @@ void processrad(uint8_t *buf, int len, char socket_index) LOG(3, s, session[s].tunnel, " Radius reply contains primary DNS address %s\n", fmtaddr(htonl(session[s].dns1), 0)); } - else if (*p == 27) - { - // Session timeout - if (p[1] < 6) { - LOG(2, s, session[s].tunnel, "Error: Received Session timeout with length %d < 6\n", p[1]); - continue; - } - - session[s].timeout = ntohl(*(uint32_t *) (p + 2)); - LOG(3, s, session[s].tunnel, " Radius reply contains Session timeout %d\n", session[s].timeout); - if (!session[s].timeout) - sessionshutdown(s, "Session timeout is zero", CDN_ADMIN_DISC, TERM_SESSION_TIMEOUT); - } else if (*p == 136) { // DNS address @@ -617,7 +703,7 @@ void processrad(uint8_t *buf, int len, char socket_index) else if (*p == 22) { // Framed-Route - in_addr_t ip = 0, mask = 0; + in_addr_t ip = 0; uint8_t u = 0; uint8_t bits = 0; uint8_t *n = p + 2; @@ -639,14 +725,13 @@ void processrad(uint8_t *buf, int len, char socket_index) n++; while (n < e && isdigit(*n)) bits = bits * 10 + *n++ - '0'; - mask = (( -1) << (32 - bits)); } else if ((ip >> 24) < 128) - mask = 0xFF0000; + bits = 8; else if ((ip >> 24) < 192) - mask = 0xFFFF0000; + bits = 16; else - mask = 0xFFFFFF00; + bits = 24; if (routes == MAXROUTE) { @@ -654,11 +739,11 @@ void processrad(uint8_t *buf, int len, char socket_index) } else if (ip) { - LOG(3, s, session[s].tunnel, " Radius reply contains route for %s/%s\n", - fmtaddr(htonl(ip), 0), fmtaddr(htonl(mask), 1)); + LOG(3, s, session[s].tunnel, " Radius reply contains route for %s/%d\n", + fmtaddr(htonl(ip), 0), bits); session[s].route[routes].ip = ip; - session[s].route[routes].mask = mask; + session[s].route[routes].prefixlen = bits; routes++; } } @@ -699,27 +784,21 @@ void processrad(uint8_t *buf, int len, char socket_index) ip_filters[f].used++; } } - else if (*p == 26 && p[1] >= 7) + else if (*p == 27) { - // Vendor-Specific Attribute - int vendor = ntohl(*(int *)(p + 2)); - char attrib = *(p + 6); - int attrib_length = *(p + 7) - 2; - - LOG(3, s, session[s].tunnel, " Radius reply contains Vendor-Specific. Vendor=%d Attrib=%d Length=%d\n", vendor, attrib, attrib_length); - if (vendor != 9 || attrib != 1) - { - LOG(3, s, session[s].tunnel, " Unknown vendor-specific\n"); - continue; - } - - if (attrib_length > 0) - { - LOG(3, s, session[s].tunnel, " Cisco-AVPair value: %.*s\n", - attrib_length, p + 8); - - handle_avpair(s, p + 8, attrib_length); - } + // Session-Timeout + if (p[1] < 6) continue; + session[s].session_timeout = ntohl(*(uint32_t *)(p + 2)); + LOG(3, s, session[s].tunnel, " Radius reply contains Session-Timeout = %u\n", session[s].session_timeout); + if(!session[s].session_timeout && config->kill_timedout_sessions) + sessionshutdown(s, "Session timeout is zero", CDN_ADMIN_DISC, 0); + } + else if (*p == 28) + { + // Idle-Timeout + if (p[1] < 6) continue; + session[s].idle_timeout = ntohl(*(uint32_t *)(p + 2)); + LOG(3, s, session[s].tunnel, " Radius reply contains Idle-Timeout = %u\n", session[s].idle_timeout); } else if (*p == 99) { @@ -747,6 +826,103 @@ void processrad(uint8_t *buf, int len, char socket_index) session[s].ipv6prefixlen = prefixlen; } } + else if (*p == 25) + { + // Class + if (p[1] < 3) continue; + session[s].classlen = p[1] - 2; + if (session[s].classlen > MAXCLASS) + session[s].classlen = MAXCLASS; + memcpy(session[s].class, p + 2, session[s].classlen); + } + else if (*p == 64) + { + // Tunnel-Type + if (p[1] != 6) continue; + tag = p[2]; + LOG(3, s, session[s].tunnel, " Radius reply Tunnel-Type:%d %d\n", + tag, ntohl(*(uint32_t *)(p + 2)) & 0xFFFFFF); + // Fill context + lac_set_rad_tag_tunnel_type(tag, ntohl(*(uint32_t *)(p + 2)) & 0xFFFFFF); + /* Request open tunnel to remote LNS*/ + OpentunnelReq = 1; + } + else if (*p == 65) + { + // Tunnel-Medium-Type + if (p[1] < 6) continue; + tag = p[2]; + LOG(3, s, session[s].tunnel, " Radius reply Tunnel-Medium-Type:%d %d\n", + tag, ntohl(*(uint32_t *)(p + 2)) & 0xFFFFFF); + // Fill context + lac_set_rad_tag_tunnel_medium_type(tag, ntohl(*(uint32_t *)(p + 2)) & 0xFFFFFF); + } + else if (*p == 67) + { + // Tunnel-Server-Endpoint + if (p[1] < 3) continue; + tag = p[2]; + //If the Tag field is greater than 0x1F, + // it SHOULD be interpreted as the first byte of the following String field. + memset(strtemp, 0, 256); + if (tag > 0x1F) + { + tag = 0; + memcpy(strtemp, (p + 2), p[1]-2); + } + else + memcpy(strtemp, (p + 3), p[1]-3); + + LOG(3, s, session[s].tunnel, " Radius reply Tunnel-Server-Endpoint:%d %s\n", tag, strtemp); + // Fill context + lac_set_rad_tag_tunnel_serv_endpt(tag, (char *) strtemp); + } + else if (*p == 69) + { + // Tunnel-Password + size_t lentemp; + + if (p[1] < 5) continue; + tag = p[2]; + + memset(strtemp, 0, 256); + lentemp = p[1]-3; + memcpy(strtemp, (p + 3), lentemp); + if (!rad_tunnel_pwdecode(strtemp, &lentemp, config->radiussecret, radius[r].auth)) + { + LOG_HEX(3, "Error Decode Tunnel-Password, Dump Radius reponse:", p, p[1]); + continue; + } + + LOG(3, s, session[s].tunnel, " Radius reply Tunnel-Password:%d %s\n", tag, strtemp); + if (strlen((char *) strtemp) > 63) + { + LOG(1, s, session[s].tunnel, "tunnel password is too long (>63)\n"); + continue; + } + // Fill context + lac_set_rad_tag_tunnel_password(tag, (char *) strtemp); + } + else if (*p == 82) + { + // Tunnel-Assignment-Id + if (p[1] < 3) continue; + tag = p[2]; + //If the Tag field is greater than 0x1F, + // it SHOULD be interpreted as the first byte of the following String field. + memset(strtemp, 0, 256); + if (tag > 0x1F) + { + tag = 0; + memcpy(strtemp, (p + 2), p[1]-2); + } + else + memcpy(strtemp, (p + 3), p[1]-3); + + LOG(3, s, session[s].tunnel, " Radius reply Tunnel-Assignment-Id:%d %s\n", tag, strtemp); + // Fill context + lac_set_rad_tag_tunnel_assignment_id(tag, (char *) strtemp); + } } } else if (r_code == AccessReject) @@ -756,6 +932,63 @@ void processrad(uint8_t *buf, int len, char socket_index) break; } + if ((!config->disable_lac_func) && OpentunnelReq) + { + char assignment_id[256]; + // Save radius tag context to conf + lac_save_rad_tag_tunnels(s); + + memset(assignment_id, 0, 256); + if (!lac_rad_select_assignment_id(s, assignment_id)) + break; // Error no assignment_id + + LOG(3, s, session[s].tunnel, "Select Tunnel Remote LNS for assignment_id == %s\n", assignment_id); + + if (lac_rad_forwardtoremotelns(s, assignment_id, session[s].user)) + { + int ro; + // Sanity check, no local IP to session forwarded + session[s].ip = 0; + for (ro = 0; r < MAXROUTE && session[s].route[ro].ip; r++) + { + session[s].route[ro].ip = 0; + } + break; + } + } + + // process auth response + if (radius[r].chap) + { + // CHAP + uint8_t *p = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP, 0, 0, 0); + if (!p) return; // Abort! + + *p = (r_code == AccessAccept) ? 3 : 4; // ack/nak + p[1] = radius[r].id; + *(uint16_t *) (p + 2) = ntohs(4); // no message + tunnelsend(b, (p - b) + 4, t); // send it + + LOG(3, s, session[s].tunnel, " CHAP User %s authentication %s.\n", session[s].user, + (r_code == AccessAccept) ? "allowed" : "denied"); + } + else + { + // PAP + uint8_t *p = makeppp(b, sizeof(b), 0, 0, s, t, PPPPAP, 0, 0, 0); + if (!p) return; // Abort! + + // ack/nak + *p = r_code; + p[1] = radius[r].id; + *(uint16_t *) (p + 2) = ntohs(5); + p[4] = 0; // no message + tunnelsend(b, (p - b) + 5, t); // send it + + LOG(3, s, session[s].tunnel, " PAP User %s authentication %s.\n", session[s].user, + (r_code == AccessAccept) ? "allowed" : "denied"); + } + if (!session[s].dns1 && config->default_dns1) { session[s].dns1 = ntohl(config->default_dns1); @@ -799,6 +1032,7 @@ void radiusretry(uint16_t r) sendchap(s, t); break; case RADIUSAUTH: // sending auth to RADIUS server + case RADIUSJUSTAUTH: // sending auth to RADIUS server case RADIUSSTART: // sending start accounting to RADIUS server case RADIUSSTOP: // sending stop accounting to RADIUS server case RADIUSINTERIM: // sending interim accounting to RADIUS server @@ -1097,3 +1331,94 @@ void processdae(uint8_t *buf, int len, struct sockaddr_in *addr, int alen, struc if (sendtofrom(daefd, buf, len, MSG_DONTWAIT | MSG_NOSIGNAL, (struct sockaddr *) addr, alen, local) < 0) LOG(0, 0, 0, "Error sending DAE response packet: %s\n", strerror(errno)); } + +// Decrypte the encrypted Tunnel Password. +// Defined in RFC-2868. +// the pl2tpsecret buffer must set to 256 characters. +// return 0 on decoding error else length of decoded l2tpsecret +int rad_tunnel_pwdecode(uint8_t *pl2tpsecret, size_t *pl2tpsecretlen, + const char *radiussecret, const uint8_t * auth) +{ + MD5_CTX ctx, oldctx; + hasht hash; + int secretlen; + unsigned i, n, len, decodedlen; + +/* 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 6 7 +* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Salt | Salt | String .......... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*/ + + len = *pl2tpsecretlen; + + if (len < 2) + { + LOG(1, 0, 0, "tunnel password is too short, We need at least a salt\n"); + return 0; + } + + if (len <= 3) + { + pl2tpsecret[0] = 0; + *pl2tpsecretlen = 0; + LOG(1, 0, 0, "tunnel passwd is empty !!!\n"); + return 0; + } + + len -= 2; /* discount the salt */ + + //Use the secret to setup the decryption + secretlen = strlen(radiussecret); + + MD5_Init(&ctx); + MD5_Update(&ctx, (void *) radiussecret, secretlen); + oldctx = ctx; /* save intermediate work */ + + // Set up the initial key: + // b(1) = MD5(radiussecret + auth + salt) + MD5_Update(&ctx, (void *) auth, 16); + MD5_Update(&ctx, pl2tpsecret, 2); + + decodedlen = 0; + for (n = 0; n < len; n += 16) + { + int base = 0; + + if (n == 0) + { + MD5_Final(hash, &ctx); + + ctx = oldctx; + + // the first octet, it's the 'data_len' + // Check is correct + decodedlen = pl2tpsecret[2] ^ hash[0]; + if (decodedlen >= len) + { + LOG(1, 0, 0, "tunnel password is too long !!!\n"); + return 0; + } + + MD5_Update(&ctx, pl2tpsecret + 2, 16); + base = 1; + } else + { + MD5_Final(hash, &ctx); + + ctx = oldctx; + MD5_Update(&ctx, pl2tpsecret + n + 2, 16); + } + + for (i = base; i < 16; i++) + { + pl2tpsecret[n + i - 1] = pl2tpsecret[n + i + 2] ^ hash[i]; + } + } + + if (decodedlen > 239) decodedlen = 239; + + *pl2tpsecretlen = decodedlen; + pl2tpsecret[decodedlen] = 0; + + return decodedlen; +};