/* $NetBSD: ip_tftp_pxy.c,v 1.6 2018/06/03 10:37:23 maxv Exp $ */ /* * Copyright (C) 2012 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. * * Id: ip_tftp_pxy.c,v 1.1.1.2 2012/07/22 13:45:38 darrenr Exp */ #define IPF_TFTP_PROXY typedef struct ipf_tftp_softc_s { int ipf_p_tftp_readonly; ipftuneable_t *ipf_p_tftp_tune; } ipf_tftp_softc_t; int ipf_p_tftp_backchannel(fr_info_t *, ap_session_t *, nat_t *); int ipf_p_tftp_client(ipf_tftp_softc_t *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_tftp_in(void *, fr_info_t *, ap_session_t *, nat_t *); void ipf_p_tftp_main_load(void); void ipf_p_tftp_main_unload(void); int ipf_p_tftp_new(void *, fr_info_t *, ap_session_t *, nat_t *); void ipf_p_tftp_del(ipf_main_softc_t *, ap_session_t *); int ipf_p_tftp_out(void *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_tftp_server(ipf_tftp_softc_t *, fr_info_t *, ap_session_t *, nat_t *); void *ipf_p_tftp_soft_create(ipf_main_softc_t *); void ipf_p_tftp_soft_destroy(ipf_main_softc_t *, void *); static frentry_t tftpfr; static int tftp_proxy_init = 0; typedef enum tftp_cmd_e { TFTP_CMD_READ = 1, TFTP_CMD_WRITE = 2, TFTP_CMD_DATA = 3, TFTP_CMD_ACK = 4, TFTP_CMD_ERROR = 5 } tftp_cmd_t; typedef struct tftpinfo { tftp_cmd_t ti_lastcmd; int ti_nextblk; int ti_lastblk; int ti_lasterror; char ti_filename[80]; ipnat_t *ti_rule; } tftpinfo_t; static const ipftuneable_t ipf_tftp_tuneables[] = { { { (void *)offsetof(ipf_tftp_softc_t, ipf_p_tftp_readonly) }, "tftp_read_only", 0, 1, stsizeof(ipf_tftp_softc_t, ipf_p_tftp_readonly), 0, NULL, NULL }, { { NULL }, NULL, 0, 0, 0, 0, NULL, NULL } }; /* * TFTP application proxy initialization. */ void ipf_p_tftp_main_load(void) { bzero((char *)&tftpfr, sizeof(tftpfr)); tftpfr.fr_ref = 1; tftpfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE; MUTEX_INIT(&tftpfr.fr_lock, "TFTP proxy rule lock"); tftp_proxy_init = 1; } void ipf_p_tftp_main_unload(void) { if (tftp_proxy_init == 1) { MUTEX_DESTROY(&tftpfr.fr_lock); tftp_proxy_init = 0; } } void * ipf_p_tftp_soft_create(ipf_main_softc_t *softc) { ipf_tftp_softc_t *softt; KMALLOC(softt, ipf_tftp_softc_t *); if (softt == NULL) return NULL; bzero((char *)softt, sizeof(*softt)); softt->ipf_p_tftp_tune = ipf_tune_array_copy(softt, sizeof(ipf_tftp_tuneables), ipf_tftp_tuneables); if (softt->ipf_p_tftp_tune == NULL) { ipf_p_tftp_soft_destroy(softc, softt); return NULL; } if (ipf_tune_array_link(softc, softt->ipf_p_tftp_tune) == -1) { ipf_p_tftp_soft_destroy(softc, softt); return NULL; } softt->ipf_p_tftp_readonly = 1; return softt; } void ipf_p_tftp_soft_destroy(ipf_main_softc_t *softc, void *arg) { ipf_tftp_softc_t *softt = arg; if (softt->ipf_p_tftp_tune != NULL) { ipf_tune_array_unlink(softc, softt->ipf_p_tftp_tune); KFREES(softt->ipf_p_tftp_tune, sizeof(ipf_tftp_tuneables)); softt->ipf_p_tftp_tune = NULL; } KFREE(softt); } int ipf_p_tftp_out(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ipf_tftp_softc_t *softt = arg; fin->fin_flx |= FI_NOWILD; if (nat->nat_dir == NAT_OUTBOUND) return ipf_p_tftp_client(softt, fin, aps, nat); return ipf_p_tftp_server(softt, fin, aps, nat); } int ipf_p_tftp_in(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ipf_tftp_softc_t *softt = arg; fin->fin_flx |= FI_NOWILD; if (nat->nat_dir == NAT_INBOUND) return ipf_p_tftp_client(softt, fin, aps, nat); return ipf_p_tftp_server(softt, fin, aps, nat); } int ipf_p_tftp_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { udphdr_t *udp; tftpinfo_t *ti; ipnat_t *ipn; ipnat_t *np; int size; fin = fin; /* LINT */ np = nat->nat_ptr; size = np->in_size; KMALLOC(ti, tftpinfo_t *); if (ti == NULL) return -1; KMALLOCS(ipn, ipnat_t *, size); if (ipn == NULL) { KFREE(ti); return -1; } aps->aps_data = ti; aps->aps_psiz = sizeof(*ti); bzero((char *)ti, sizeof(*ti)); bzero((char *)ipn, size); ti->ti_rule = ipn; udp = (udphdr_t *)fin->fin_dp; aps->aps_sport = udp->uh_sport; aps->aps_dport = udp->uh_dport; ipn->in_size = size; ipn->in_apr = NULL; ipn->in_use = 1; ipn->in_hits = 1; ipn->in_ippip = 1; ipn->in_pr[0] = IPPROTO_UDP; ipn->in_pr[1] = IPPROTO_UDP; ipn->in_ifps[0] = nat->nat_ifps[0]; ipn->in_ifps[1] = nat->nat_ifps[1]; ipn->in_v[0] = nat->nat_ptr->in_v[1]; ipn->in_v[1] = nat->nat_ptr->in_v[0]; ipn->in_flags = IPN_UDP|IPN_FIXEDDPORT|IPN_PROXYRULE; ipn->in_nsrcip6 = nat->nat_odst6; ipn->in_osrcip6 = nat->nat_ndst6; if ((np->in_redir & NAT_REDIRECT) != 0) { ipn->in_redir = NAT_MAP; if (ipn->in_v[0] == 4) { ipn->in_snip = ntohl(nat->nat_odstaddr); ipn->in_dnip = ntohl(nat->nat_nsrcaddr); } else { #ifdef USE_INET6 ipn->in_snip6 = nat->nat_odst6; ipn->in_dnip6 = nat->nat_nsrc6; #endif } ipn->in_ndstip6 = nat->nat_nsrc6; ipn->in_odstip6 = nat->nat_osrc6; } else { ipn->in_redir = NAT_REDIRECT; if (ipn->in_v[0] == 4) { ipn->in_snip = ntohl(nat->nat_odstaddr); ipn->in_dnip = ntohl(nat->nat_osrcaddr); } else { #ifdef USE_INET6 ipn->in_snip6 = nat->nat_odst6; ipn->in_dnip6 = nat->nat_osrc6; #endif } ipn->in_ndstip6 = nat->nat_osrc6; ipn->in_odstip6 = nat->nat_nsrc6; } ipn->in_odport = htons(fin->fin_sport); ipn->in_ndport = htons(fin->fin_sport); IP6_SETONES(&ipn->in_osrcmsk6); IP6_SETONES(&ipn->in_nsrcmsk6); IP6_SETONES(&ipn->in_odstmsk6); IP6_SETONES(&ipn->in_ndstmsk6); MUTEX_INIT(&ipn->in_lock, "tftp proxy NAT rule"); ipn->in_namelen = np->in_namelen; bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen); ipn->in_ifnames[0] = np->in_ifnames[0]; ipn->in_ifnames[1] = np->in_ifnames[1]; ti->ti_lastcmd = 0; return 0; } void ipf_p_tftp_del(ipf_main_softc_t *softc, ap_session_t *aps) { tftpinfo_t *tftp; tftp = aps->aps_data; if (tftp != NULL) { tftp->ti_rule->in_flags |= IPN_DELETE; ipf_nat_rule_deref(softc, &tftp->ti_rule); } } /* * Setup for a new TFTP proxy. */ int ipf_p_tftp_backchannel(fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ipf_main_softc_t *softc = fin->fin_main_soft; #ifdef USE_MUTEXES ipf_nat_softc_t *softn = softc->ipf_nat_soft; #endif #ifdef USE_INET6 i6addr_t swip6, sw2ip6; ip6_t *ip6; #endif struct in_addr swip, sw2ip; tftpinfo_t *ti; udphdr_t udp; fr_info_t fi; u_short slen = 0; nat_t *nat2 = NULL; int nflags; ip_t *ip; int dir; ti = aps->aps_data; /* * Add skeleton NAT entry for connection which will come back the * other way. */ bcopy((char *)fin, (char *)&fi, sizeof(fi)); fi.fin_flx |= FI_IGNORE; fi.fin_data[1] = 0; bzero((char *)&udp, sizeof(udp)); udp.uh_sport = 0; /* XXX - don't specify remote port */ udp.uh_dport = ti->ti_rule->in_ndport; udp.uh_ulen = htons(sizeof(udp)); udp.uh_sum = 0; fi.fin_fr = &tftpfr; fi.fin_dp = (char *)&udp; fi.fin_sport = 0; fi.fin_dport = ntohs(ti->ti_rule->in_ndport); fi.fin_dlen = sizeof(udp); fi.fin_plen = fi.fin_hlen + sizeof(udp); fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE; nflags = NAT_SLAVE|IPN_UDP|SI_W_SPORT; #ifdef USE_INET6 ip6 = (ip6_t *)fin->fin_ip; #endif ip = fin->fin_ip; sw2ip.s_addr = 0; swip.s_addr = 0; fi.fin_src6 = nat->nat_ndst6; fi.fin_dst6 = nat->nat_nsrc6; if (nat->nat_v[0] == 4) { slen = ip->ip_len; ip->ip_len = htons(fin->fin_hlen + sizeof(udp)); swip = ip->ip_src; sw2ip = ip->ip_dst; ip->ip_src = nat->nat_ndstip; ip->ip_dst = nat->nat_nsrcip; } else { #ifdef USE_INET6 slen = ip6->ip6_plen; ip6->ip6_plen = htons(sizeof(udp)); swip6.in6 = ip6->ip6_src; sw2ip6.in6 = ip6->ip6_dst; ip6->ip6_src = nat->nat_ndst6.in6; ip6->ip6_dst = nat->nat_nsrc6.in6; #endif } if (nat->nat_dir == NAT_INBOUND) { dir = NAT_OUTBOUND; fi.fin_out = 1; } else { dir = NAT_INBOUND; fi.fin_out = 0; } nflags |= NAT_NOTRULEPORT; MUTEX_ENTER(&softn->ipf_nat_new); if (nat->nat_v[0] == 4) nat2 = ipf_nat_add(&fi, ti->ti_rule, NULL, nflags, dir); #ifdef USE_INET6 else nat2 = ipf_nat6_add(&fi, ti->ti_rule, NULL, nflags, dir); #endif MUTEX_EXIT(&softn->ipf_nat_new); if (nat2 != NULL) { (void) ipf_nat_proto(&fi, nat2, IPN_UDP); ipf_nat_update(&fi, nat2); fi.fin_ifp = NULL; if (ti->ti_rule->in_redir == NAT_MAP) { fi.fin_src6 = nat->nat_ndst6; fi.fin_dst6 = nat->nat_nsrc6; if (nat->nat_v[0] == 4) { ip->ip_src = nat->nat_ndstip; ip->ip_dst = nat->nat_nsrcip; } else { #ifdef USE_INET6 ip6->ip6_src = nat->nat_ndst6.in6; ip6->ip6_dst = nat->nat_nsrc6.in6; #endif } } else { fi.fin_src6 = nat->nat_odst6; fi.fin_dst6 = nat->nat_osrc6; if (fin->fin_v == 4) { ip->ip_src = nat->nat_odstip; ip->ip_dst = nat->nat_osrcip; } else { #ifdef USE_INET6 ip6->ip6_src = nat->nat_odst6.in6; ip6->ip6_dst = nat->nat_osrc6.in6; #endif } } if (ipf_state_add(softc, &fi, NULL, SI_W_SPORT) != 0) { ipf_nat_setpending(softc, nat2); } } if (nat->nat_v[0] == 4) { ip->ip_len = slen; ip->ip_src = swip; ip->ip_dst = sw2ip; } else { #ifdef USE_INET6 ip6->ip6_plen = slen; ip6->ip6_src = swip6.in6; ip6->ip6_dst = sw2ip6.in6; #endif } return 0; } int ipf_p_tftp_client(ipf_tftp_softc_t *softt, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { u_char *msg, *s, *t; tftpinfo_t *ti; u_short opcode; udphdr_t *udp; int len; if (fin->fin_dlen < 4) return 0; ti = aps->aps_data; msg = fin->fin_dp; msg += sizeof(udphdr_t); opcode = (msg[0] << 8) | msg[1]; DT3(tftp_cmd, fr_info_t *, fin, int, opcode, nat_t *, nat); switch (opcode) { case TFTP_CMD_WRITE : if (softt->ipf_p_tftp_readonly != 0) break; /* FALLTHROUGH */ case TFTP_CMD_READ : len = fin->fin_dlen - sizeof(*udp) - 2; if (len > sizeof(ti->ti_filename) - 1) len = sizeof(ti->ti_filename) - 1; s = msg + 2; for (t = (u_char *)ti->ti_filename; (len > 0); len--, s++) { *t++ = *s; if (*s == '\0') break; } ipf_p_tftp_backchannel(fin, aps, nat); break; default : return -1; } ti = aps->aps_data; ti->ti_lastcmd = opcode; return 0; } int ipf_p_tftp_server(ipf_tftp_softc_t *softt, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { tftpinfo_t *ti; u_short opcode; u_short arg; u_char *msg; if (fin->fin_dlen < 4) return 0; ti = aps->aps_data; msg = fin->fin_dp; msg += sizeof(udphdr_t); arg = (msg[2] << 8) | msg[3]; opcode = (msg[0] << 8) | msg[1]; switch (opcode) { case TFTP_CMD_ACK : ti->ti_lastblk = arg; break; case TFTP_CMD_ERROR : ti->ti_lasterror = arg; break; default : return -1; } ti->ti_lastcmd = opcode; return 0; }