/* $NetBSD: ip_irc_pxy.c,v 1.4 2014/03/20 20:43:12 christos Exp $ */ /* * Copyright (C) 2012 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. * * Id: ip_irc_pxy.c,v 1.1.1.2 2012/07/22 13:45:19 darrenr Exp */ #include __KERNEL_RCSID(1, "$NetBSD: ip_irc_pxy.c,v 1.4 2014/03/20 20:43:12 christos Exp $"); #define IPF_IRC_PROXY #define IPF_IRCBUFSZ 96 /* This *MUST* be >= 64! */ void ipf_p_irc_main_load(void); void ipf_p_irc_main_unload(void); int ipf_p_irc_new(void *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_irc_out(void *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_irc_send(fr_info_t *, nat_t *); int ipf_p_irc_complete(ircinfo_t *, char *, size_t); u_short ipf_irc_atoi(char **); static frentry_t ircnatfr; int irc_proxy_init = 0; /* * Initialize local structures. */ void ipf_p_irc_main_load(void) { bzero((char *)&ircnatfr, sizeof(ircnatfr)); ircnatfr.fr_ref = 1; ircnatfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE; MUTEX_INIT(&ircnatfr.fr_lock, "IRC proxy rule lock"); irc_proxy_init = 1; } void ipf_p_irc_main_unload(void) { if (irc_proxy_init == 1) { MUTEX_DESTROY(&ircnatfr.fr_lock); irc_proxy_init = 0; } } const char *ipf_p_irc_dcctypes[] = { "CHAT ", /* CHAT chat ipnumber portnumber */ "SEND ", /* SEND filename ipnumber portnumber */ "MOVE ", "TSEND ", "SCHAT ", NULL, }; /* * :A PRIVMSG B :^ADCC CHAT chat 0 0^A\r\n * PRIVMSG B ^ADCC CHAT chat 0 0^A\r\n */ int ipf_p_irc_complete(ircinfo_t *ircp, char *buf, size_t len) { register char *s, c; register size_t i; u_32_t l; int j, k; ircp->irc_ipnum = 0; ircp->irc_port = 0; if (len < 31) return 0; s = buf; c = *s++; i = len - 1; if ((c != ':') && (c != 'P')) return 0; if (c == ':') { /* * Loosely check that the source is a nickname of some sort */ s++; c = *s; ircp->irc_snick = s; if (!ISALPHA(c)) return 0; i--; for (c = *s; !ISSPACE(c) && (i > 0); i--) c = *s++; if (i < 31) return 0; if (c != 'P') return 0; } else ircp->irc_snick = NULL; /* * Check command string */ if (strncmp(s, "PRIVMSG ", 8)) return 0; i -= 8; s += 8; c = *s; ircp->irc_dnick = s; /* * Loosely check that the destination is a nickname of some sort */ if (!ISALPHA(c)) return 0; for (; !ISSPACE(c) && (i > 0); i--) c = *s++; if (i < 20) return 0; s++, i--; /* * Look for a ^A to start the DCC */ c = *s; if (c == ':') { s++; c = *s; } if (strncmp(s, "\001DCC ", 4)) return 0; i -= 4; s += 4; /* * Check for a recognised DCC command */ for (j = 0, k = 0; ipf_p_irc_dcctypes[j]; j++) { k = MIN(strlen(ipf_p_irc_dcctypes[j]), i); if (!strncmp(ipf_p_irc_dcctypes[j], s, k)) break; } if (!ipf_p_irc_dcctypes[j]) return 0; ircp->irc_type = s; i -= k; s += k; if (i < 11) return 0; /* * Check for the arg */ c = *s; if (ISSPACE(c)) return 0; ircp->irc_arg = s; for (; (c != ' ') && (c != '\001') && (i > 0); i--) c = *s++; if (c == '\001') /* In reality a ^A can quote another ^A...*/ return 0; if (i < 5) return 0; s++; i--; c = *s; if (!ISDIGIT(c)) return 0; ircp->irc_addr = s; /* * Get the IP# */ for (l = 0; ISDIGIT(c) && (i > 0); i--) { l *= 10; l += c - '0'; c = *s++; } if (i < 4) return 0; if (c != ' ') return 0; ircp->irc_ipnum = l; s++; i--; c = *s; if (!ISDIGIT(c)) return 0; /* * Get the port# */ for (l = 0; ISDIGIT(c) && (i > 0); i--) { l *= 10; l += c - '0'; c = *s++; } if (i < 3) return 0; if (strncmp(s, "\001\r\n", 3)) return 0; s += 3; ircp->irc_len = s - buf; ircp->irc_port = l; return 1; } int ipf_p_irc_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ircinfo_t *irc; if (fin->fin_v != 4) return -1; KMALLOC(irc, ircinfo_t *); if (irc == NULL) return -1; nat = nat; /* LINT */ aps->aps_data = irc; aps->aps_psiz = sizeof(ircinfo_t); bzero((char *)irc, sizeof(*irc)); return 0; } int ipf_p_irc_send(fr_info_t *fin, nat_t *nat) { char ctcpbuf[IPF_IRCBUFSZ], newbuf[IPF_IRCBUFSZ]; tcphdr_t *tcp, tcph, *tcp2 = &tcph; int off, inc = 0, i, dlen; ipf_main_softc_t *softc; size_t nlen = 0, olen; struct in_addr swip; u_short a5, sp; ircinfo_t *irc; fr_info_t fi; nat_t *nat2; u_int a1; ip_t *ip; mb_t *m; #ifdef MENTAT mb_t *m1; #endif softc = fin->fin_main_soft; m = fin->fin_m; ip = fin->fin_ip; tcp = (tcphdr_t *)fin->fin_dp; bzero(ctcpbuf, sizeof(ctcpbuf)); off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff; #ifdef __sgi dlen = fin->fin_plen - off; #else dlen = MSGDSIZE(m) - off; #endif if (dlen <= 0) return 0; COPYDATA(m, off, MIN(sizeof(ctcpbuf), dlen), ctcpbuf); if (dlen <= 0) return 0; ctcpbuf[sizeof(ctcpbuf) - 1] = '\0'; *newbuf = '\0'; irc = nat->nat_aps->aps_data; if (ipf_p_irc_complete(irc, ctcpbuf, dlen) == 0) return 0; /* * check that IP address in the DCC reply is the same as the * sender of the command - prevents use for port scanning. */ if (irc->irc_ipnum != ntohl(nat->nat_osrcaddr)) return 0; a5 = irc->irc_port; /* * Calculate new address parts for the DCC command */ a1 = ntohl(ip->ip_src.s_addr); olen = irc->irc_len; i = irc->irc_addr - ctcpbuf; i++; (void) strncpy(newbuf, ctcpbuf, i); snprintf(newbuf, sizeof(newbuf) - i, "%u %u\001\r\n", a1, a5); nlen = strlen(newbuf); inc = nlen - olen; if ((inc + fin->fin_plen) > 65535) return 0; #ifdef MENTAT for (m1 = m; m1->b_cont; m1 = m1->b_cont) ; if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) { mblk_t *nm; /* alloc enough to keep same trailer space for lower driver */ nm = allocb(nlen, BPRI_MED); PANIC((!nm),("ipf_p_irc_out: allocb failed")); nm->b_band = m1->b_band; nm->b_wptr += nlen; m1->b_wptr -= olen; PANIC((m1->b_wptr < m1->b_rptr), ("ipf_p_irc_out: cannot handle fragmented data block")); linkb(m1, nm); } else { # if SOLARIS && defined(ICK_VALID) if (m1->b_datap->db_struiolim == m1->b_wptr) m1->b_datap->db_struiolim += inc; m1->b_datap->db_struioflag &= ~STRUIO_IP; # endif m1->b_wptr += inc; } #else if (inc < 0) m_adj(m, inc); /* the mbuf chain will be extended if necessary by m_copyback() */ #endif COPYBACK(m, off, nlen, newbuf); fin->fin_flx |= FI_DOCKSUM; if (inc != 0) { #if defined(MENTAT) || defined(__sgi) register u_32_t sum1, sum2; sum1 = fin->fin_plen; sum2 = fin->fin_plen + inc; /* Because ~1 == -2, We really need ~1 == -1 */ if (sum1 > sum2) sum2--; sum2 -= sum1; sum2 = (sum2 & 0xffff) + (sum2 >> 16); ipf_fix_outcksum(0, &ip->ip_sum, sum2, 0); #endif fin->fin_plen += inc; ip->ip_len = htons(fin->fin_plen); fin->fin_dlen += inc; } /* * Add skeleton NAT entry for connection which will come back the * other way. */ sp = htons(a5); /* * Don't allow the PORT command to specify a port < 1024 due to * security crap. */ if (ntohs(sp) < 1024) return 0; /* * The server may not make the connection back from port 20, but * it is the most likely so use it here to check for a conflicting * mapping. */ bcopy((void *)fin, (void *)&fi, sizeof(fi)); fi.fin_data[0] = sp; fi.fin_data[1] = fin->fin_data[1]; nat2 = ipf_nat_outlookup(fin, IPN_TCP, nat->nat_pr[1], nat->nat_nsrcip, ip->ip_dst); if (nat2 == NULL) { #ifdef USE_MUTEXES ipf_nat_softc_t *softn = softc->ipf_nat_soft; #endif bcopy((void *)fin, (void *)&fi, sizeof(fi)); bzero((char *)tcp2, sizeof(*tcp2)); tcp2->th_win = htons(8192); tcp2->th_sport = sp; tcp2->th_dport = 0; /* XXX - don't specify remote port */ fi.fin_data[0] = ntohs(sp); fi.fin_data[1] = 0; fi.fin_dp = (char *)tcp2; fi.fin_fr = &ircnatfr; fi.fin_dlen = sizeof(*tcp2); fi.fin_plen = fi.fin_hlen + sizeof(*tcp2); swip = ip->ip_src; ip->ip_src = nat->nat_nsrcip; MUTEX_ENTER(&softn->ipf_nat_new); nat2 = ipf_nat_add(&fi, nat->nat_ptr, NULL, NAT_SLAVE|IPN_TCP|SI_W_DPORT, NAT_OUTBOUND); MUTEX_EXIT(&softn->ipf_nat_new); if (nat2 != NULL) { (void) ipf_nat_proto(&fi, nat2, 0); MUTEX_ENTER(&nat2->nat_lock); ipf_nat_update(&fi, nat2); MUTEX_EXIT(&nat2->nat_lock); (void) ipf_state_add(softc, &fi, NULL, SI_W_DPORT); } ip->ip_src = swip; } return inc; } int ipf_p_irc_out(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { aps = aps; /* LINT */ return ipf_p_irc_send(fin, nat); }