X-Git-Url: https://git.decadent.org.uk/gitweb/?a=blobdiff_plain;f=src%2Fdhcpv6.c;h=86f24e070bf9d5c6d4ecc66a4e2c1c12380c3d71;hb=4369d2f0e1ab9682d677f2f8fd876329e740fb0b;hp=4bca6e78e6f85b34383215335c825d8426d17232;hpb=f157601cf149ddd062dec1ef8fca02349a0cb8a9;p=odhcp6c.git diff --git a/src/dhcpv6.c b/src/dhcpv6.c index 4bca6e7..86f24e0 100644 --- a/src/dhcpv6.c +++ b/src/dhcpv6.c @@ -1,5 +1,5 @@ /** - * Copyright (C) 2012 Steven Barth + * Copyright (C) 2012-2013 Steven Barth * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License v2 as published by @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -31,6 +32,7 @@ #include #include "odhcp6c.h" +#include "md5.h" #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\ @@ -44,7 +46,7 @@ static bool dhcpv6_response_is_valid(const void *buf, ssize_t len, const uint8_t transaction[3], enum dhcpv6_msg type); -static time_t dhcpv6_parse_ia(void *opt, void *end); +static uint32_t dhcpv6_parse_ia(void *opt, void *end); static reply_handler dhcpv6_handle_reply; static reply_handler dhcpv6_handle_advert; @@ -76,13 +78,16 @@ static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = { // Sockets static int sock = -1; static int ifindex = -1; -static time_t t1 = 0, t2 = 0, t3 = 0; +static int64_t t1 = 0, t2 = 0, t3 = 0; // IA states static int request_prefix = -1; static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE; static bool accept_reconfig = false; +// Reconfigure key +static uint8_t reconf_key[16]; + int init_dhcpv6(const char *ifname, int request_pd) @@ -135,7 +140,8 @@ int init_dhcpv6(const char *ifname, int request_pd) htons(DHCPV6_OPT_DNS_DOMAIN), htons(DHCPV6_OPT_NTP_SERVER), htons(DHCPV6_OPT_SIP_SERVER_A), - htons(DHCPV6_OPT_SIP_SERVER_D)}; + htons(DHCPV6_OPT_SIP_SERVER_D), + htons(DHCPV6_OPT_PD_EXCLUDE)}; odhcp6c_add_state(STATE_ORO, oro, sizeof(oro)); @@ -188,7 +194,6 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs) // Build IA_PDs size_t ia_pd_entries, ia_pd_len = 0; - void *ia_pd = NULL; struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries); ia_pd_entries /= sizeof(*e); struct dhcpv6_ia_hdr hdr_ia_pd = { @@ -197,32 +202,51 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs) 1, 0, 0 }; - struct dhcpv6_ia_prefix pref = { - .type = htons(DHCPV6_OPT_IA_PREFIX), - .len = htons(25), .prefix = request_prefix - }; - - struct dhcpv6_ia_prefix p[ia_pd_entries]; + uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10)); for (size_t i = 0; i < ia_pd_entries; ++i) { - p[i].type = htons(DHCPV6_OPT_IA_PREFIX); - p[i].len = htons(sizeof(p[i]) - 4U); - p[i].preferred = htonl(e[i].preferred); - p[i].valid = htonl(e[i].valid); - p[i].prefix = e[i].length; - p[i].addr = e[i].target; + uint8_t ex_len = 0; + if (e[i].priority > 0) + ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6; + + struct dhcpv6_ia_prefix p = { + .type = htons(DHCPV6_OPT_IA_PREFIX), + .len = htons(sizeof(p) - 4U + ex_len), + .prefix = e[i].length, + .addr = e[i].target + }; + + memcpy(ia_pd + ia_pd_len, &p, sizeof(p)); + ia_pd_len += sizeof(p); + + if (ex_len) { + ia_pd[ia_pd_len++] = 0; + ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE; + ia_pd[ia_pd_len++] = 0; + ia_pd[ia_pd_len++] = ex_len - 4; + ia_pd[ia_pd_len++] = e[i].priority; + + uint32_t excl = ntohl(e[i].router.s6_addr32[1]); + excl >>= (64 - e[i].priority); + excl <<= 8 - ((e[i].priority - e[i].length) % 8); + + for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8) + ia_pd[ia_pd_len + i] = excl & 0xff; + ia_pd_len += ex_len - 5; + } } - ia_pd = p; - ia_pd_len = sizeof(p); - hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len); - if (request_prefix > 0 && + struct dhcpv6_ia_prefix pref = { + .type = htons(DHCPV6_OPT_IA_PREFIX), + .len = htons(25), .prefix = request_prefix + }; + if (request_prefix > 0 && ia_pd_len == 0 && (type == DHCPV6_MSG_SOLICIT || type == DHCPV6_MSG_REQUEST)) { - ia_pd = &pref; + ia_pd = (uint8_t*)&pref; ia_pd_len = sizeof(pref); - hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len); } + hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len); // Build IA_NAs size_t ia_na_entries, ia_na_len = 0; @@ -241,8 +265,8 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs) pa[i].type = htons(DHCPV6_OPT_IA_ADDR); pa[i].len = htons(sizeof(pa[i]) - 4U); pa[i].addr = e[i].target; - pa[i].preferred = htonl(e[i].preferred); - pa[i].valid = htonl(e[i].valid); + pa[i].preferred = 0; + pa[i].valid = 0; } ia_na = pa; @@ -450,19 +474,55 @@ static bool dhcpv6_response_is_valid(const void *buf, ssize_t len, uint8_t *end = ((uint8_t*)buf) + len, *odata; uint16_t otype, olen; - bool clientid_ok = false, serverid_ok = false; + bool clientid_ok = false, serverid_ok = false, rcauth_ok = false; size_t client_id_len, server_id_len; void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len); void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len); - dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) - if (otype == DHCPV6_OPT_CLIENTID) + dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) { + if (otype == DHCPV6_OPT_CLIENTID) { clientid_ok = (olen + 4U == client_id_len) && !memcmp( &odata[-4], client_id, client_id_len); - else if (otype == DHCPV6_OPT_SERVERID) + } else if (otype == DHCPV6_OPT_SERVERID) { serverid_ok = (olen + 4U == server_id_len) && !memcmp( &odata[-4], server_id, server_id_len); + } else if (otype == DHCPV6_OPT_AUTH && olen == -4 + + sizeof(struct dhcpv6_auth_reconfigure)) { + struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4]; + if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2) + continue; + + md5_state_t md5; + uint8_t serverhash[16], secretbytes[16], hash[16]; + memcpy(serverhash, r->key, sizeof(serverhash)); + memset(r->key, 0, sizeof(r->key)); + memcpy(secretbytes, reconf_key, sizeof(secretbytes)); + + for (size_t i = 0; i < sizeof(secretbytes); ++i) + secretbytes[i] ^= 0x36; + + md5_init(&md5); + md5_append(&md5, secretbytes, sizeof(secretbytes)); + md5_append(&md5, buf, len); + md5_finish(&md5, hash); + + for (size_t i = 0; i < sizeof(secretbytes); ++i) { + secretbytes[i] ^= 0x36; + secretbytes[i] ^= 0x5c; + } + + md5_init(&md5); + md5_append(&md5, secretbytes, sizeof(secretbytes)); + md5_append(&md5, hash, 16); + md5_finish(&md5, hash); + + rcauth_ok = !memcmp(hash, serverhash, sizeof(hash)); + } + } + + if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok) + return false; return clientid_ok && (serverid_ok || server_id_len == 0); } @@ -520,7 +580,7 @@ static int dhcpv6_handle_advert(_unused enum dhcpv6_msg orig, cand.preference -= 2000; } else if (otype == DHCPV6_OPT_PREF && olen >= 1 && cand.preference >= 0) { - cand.preference = odata[1]; + cand.preference = odata[0]; } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) { cand.wants_reconfigure = true; } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) { @@ -623,7 +683,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, if (t3 < 0) t3 = 0; } else { - t1 = t2 = t3 = 86400; + t1 = t2 = t3 = UINT32_MAX; } if (opt) { @@ -640,13 +700,14 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) && olen > sizeof(struct dhcpv6_ia_hdr)) { struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]); - time_t l_t1 = ntohl(ia_hdr->t1); - time_t l_t2 = ntohl(ia_hdr->t2); + uint32_t l_t1 = ntohl(ia_hdr->t1); + uint32_t l_t2 = ntohl(ia_hdr->t2); // Test ID and T1-T2 validity if (ia_hdr->iaid != 1 || l_t2 < l_t1) continue; + bool error = false; uint16_t stype, slen; uint8_t *sdata; // Test status and bail if error @@ -654,7 +715,10 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, stype, slen, sdata) if (stype == DHCPV6_OPT_STATUS && slen >= 2 && (sdata[0] || sdata[1])) - continue; + error = true; + + if (error) + continue; // Update times if (l_t1 > 0 && t1 > l_t1) @@ -663,7 +727,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, if (l_t2 > 0 && t2 > l_t2) t2 = l_t2; - time_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen); + uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen); if (n < t1) t1 = n; @@ -674,6 +738,12 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, if (n < t3) t3 = n; + if (t2 >= t3) + t2 = 8 * t3 / 10; + + if (t1 >= t2) + t1 = 5 * t2 / 8; + } else if (otype == DHCPV6_OPT_DNS_SERVERS) { if (olen % 16 == 0) odhcp6c_add_state(STATE_DNS, odata, olen); @@ -702,6 +772,12 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, uint32_t refresh = ntohl(*((uint32_t*)odata)); if (refresh < (uint32_t)t1) t1 = refresh; + } else if (otype == DHCPV6_OPT_AUTH && olen == -4 + + sizeof(struct dhcpv6_auth_reconfigure)) { + struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4]; + if (r->protocol == 3 && r->algorithm == 1 && + r->reconf_type == 1) + memcpy(reconf_key, r->key, sizeof(r->key)); } else if (otype != DHCPV6_OPT_CLIENTID && otype != DHCPV6_OPT_SERVERID) { odhcp6c_add_state(STATE_CUSTOM_OPTS, @@ -713,7 +789,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, } -static time_t dhcpv6_parse_ia(void *opt, void *end) +static uint32_t dhcpv6_parse_ia(void *opt, void *end) { uint32_t timeout = UINT32_MAX; // Minimum timeout uint16_t otype, olen; @@ -738,7 +814,50 @@ static time_t dhcpv6_parse_ia(void *opt, void *end) entry.length = prefix->prefix; entry.target = prefix->addr; - odhcp6c_update_entry(STATE_IA_PD, &entry); + // Parse PD-exclude + bool ok = true; + uint16_t stype, slen; + uint8_t *sdata; + dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U, + odata + olen, stype, slen, sdata) { + if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2) + continue; + + uint8_t elen = sdata[0]; + if (elen > 64) + elen = 64; + + if (elen <= 32 || elen <= entry.length) { + ok = false; + continue; + } + + + uint8_t bytes = ((elen - entry.length - 1) / 8) + 1; + if (slen <= bytes) { + ok = false; + continue; + } + + uint32_t exclude = 0; + do { + exclude = exclude << 8 | sdata[bytes]; + } while (--bytes); + + exclude >>= 8 - ((elen - entry.length) % 8); + exclude <<= 64 - elen; + + // Abusing router & priority fields for exclusion + entry.router = entry.target; + entry.router.s6_addr32[1] |= htonl(exclude); + entry.priority = elen; + } + + if (ok) + odhcp6c_update_entry(STATE_IA_PD, &entry); + + entry.priority = 0; + memset(&entry.router, 0, sizeof(entry.router)); } else if (otype == DHCPV6_OPT_IA_ADDR) { struct dhcpv6_ia_addr *addr = (void*)&odata[-4]; if (olen + 4U < sizeof(*addr))