ip_dns_pxy.c revision 1.2.2.2
1 1.2.2.2 joerg /* $NetBSD: ip_dns_pxy.c,v 1.2.2.2 2012/04/17 19:25:18 joerg Exp $ */ 2 1.2.2.2 joerg 3 1.2.2.2 joerg /* 4 1.2.2.2 joerg * Copyright (C) 2010 by Darren Reed. 5 1.2.2.2 joerg * 6 1.2.2.2 joerg * See the IPFILTER.LICENCE file for details on licencing. 7 1.2.2.2 joerg * 8 1.2.2.2 joerg * Id: ip_dns_pxy.c,v 2.2.2.6 2012/01/29 05:30:35 darrenr Exp 9 1.2.2.2 joerg */ 10 1.2.2.2 joerg 11 1.2.2.2 joerg #define IPF_DNS_PROXY 12 1.2.2.2 joerg 13 1.2.2.2 joerg /* 14 1.2.2.2 joerg * map ... proxy port dns/udp 53 { block .cnn.com; } 15 1.2.2.2 joerg */ 16 1.2.2.2 joerg typedef struct ipf_dns_filter { 17 1.2.2.2 joerg struct ipf_dns_filter *idns_next; 18 1.2.2.2 joerg char *idns_name; 19 1.2.2.2 joerg int idns_namelen; 20 1.2.2.2 joerg int idns_pass; 21 1.2.2.2 joerg } ipf_dns_filter_t; 22 1.2.2.2 joerg 23 1.2.2.2 joerg 24 1.2.2.2 joerg typedef struct ipf_dns_softc_s { 25 1.2.2.2 joerg ipf_dns_filter_t *ipf_p_dns_list; 26 1.2.2.2 joerg ipfrwlock_t ipf_p_dns_rwlock; 27 1.2.2.2 joerg u_long ipf_p_dns_compress; 28 1.2.2.2 joerg u_long ipf_p_dns_toolong; 29 1.2.2.2 joerg u_long ipf_p_dns_nospace; 30 1.2.2.2 joerg } ipf_dns_softc_t; 31 1.2.2.2 joerg 32 1.2.2.2 joerg int ipf_p_dns_allow_query(ipf_dns_softc_t *, dnsinfo_t *); 33 1.2.2.2 joerg int ipf_p_dns_ctl(ipf_main_softc_t *, void *, ap_ctl_t *); 34 1.2.2.2 joerg int ipf_p_dns_del(ipf_main_softc_t *, ap_session_t *); 35 1.2.2.2 joerg int ipf_p_dns_get_name(ipf_dns_softc_t *, char *, int, char *, int); 36 1.2.2.2 joerg int ipf_p_dns_inout(void *, fr_info_t *, ap_session_t *, nat_t *); 37 1.2.2.2 joerg int ipf_p_dns_match(fr_info_t *, ap_session_t *, nat_t *); 38 1.2.2.2 joerg int ipf_p_dns_match_names(ipf_dns_filter_t *, char *, int); 39 1.2.2.2 joerg int ipf_p_dns_new(void *, fr_info_t *, ap_session_t *, nat_t *); 40 1.2.2.2 joerg void *ipf_p_dns_soft_create(ipf_main_softc_t *); 41 1.2.2.2 joerg void ipf_p_dns_soft_destroy(ipf_main_softc_t *, void *); 42 1.2.2.2 joerg 43 1.2.2.2 joerg typedef struct { 44 1.2.2.2 joerg u_char dns_id[2]; 45 1.2.2.2 joerg u_short dns_ctlword; 46 1.2.2.2 joerg u_short dns_qdcount; 47 1.2.2.2 joerg u_short dns_ancount; 48 1.2.2.2 joerg u_short dns_nscount; 49 1.2.2.2 joerg u_short dns_arcount; 50 1.2.2.2 joerg } ipf_dns_hdr_t; 51 1.2.2.2 joerg 52 1.2.2.2 joerg #define DNS_QR(x) ((ntohs(x) & 0x8000) >> 15) 53 1.2.2.2 joerg #define DNS_OPCODE(x) ((ntohs(x) & 0x7800) >> 11) 54 1.2.2.2 joerg #define DNS_AA(x) ((ntohs(x) & 0x0400) >> 10) 55 1.2.2.2 joerg #define DNS_TC(x) ((ntohs(x) & 0x0200) >> 9) 56 1.2.2.2 joerg #define DNS_RD(x) ((ntohs(x) & 0x0100) >> 8) 57 1.2.2.2 joerg #define DNS_RA(x) ((ntohs(x) & 0x0080) >> 7) 58 1.2.2.2 joerg #define DNS_Z(x) ((ntohs(x) & 0x0070) >> 4) 59 1.2.2.2 joerg #define DNS_RCODE(x) ((ntohs(x) & 0x000f) >> 0) 60 1.2.2.2 joerg 61 1.2.2.2 joerg 62 1.2.2.2 joerg void * 63 1.2.2.2 joerg ipf_p_dns_soft_create(ipf_main_softc_t *softc) 64 1.2.2.2 joerg { 65 1.2.2.2 joerg ipf_dns_softc_t *softd; 66 1.2.2.2 joerg 67 1.2.2.2 joerg KMALLOC(softd, ipf_dns_softc_t *); 68 1.2.2.2 joerg if (softd == NULL) 69 1.2.2.2 joerg return NULL; 70 1.2.2.2 joerg 71 1.2.2.2 joerg bzero((char *)softd, sizeof(*softd)); 72 1.2.2.2 joerg RWLOCK_INIT(&softd->ipf_p_dns_rwlock, "ipf dns rwlock"); 73 1.2.2.2 joerg 74 1.2.2.2 joerg return softd; 75 1.2.2.2 joerg } 76 1.2.2.2 joerg 77 1.2.2.2 joerg 78 1.2.2.2 joerg void 79 1.2.2.2 joerg ipf_p_dns_soft_destroy(ipf_main_softc_t *softc, void *arg) 80 1.2.2.2 joerg { 81 1.2.2.2 joerg ipf_dns_softc_t *softd = arg; 82 1.2.2.2 joerg ipf_dns_filter_t *idns; 83 1.2.2.2 joerg 84 1.2.2.2 joerg while ((idns = softd->ipf_p_dns_list) != NULL) { 85 1.2.2.2 joerg KFREES(idns->idns_name, idns->idns_namelen); 86 1.2.2.2 joerg idns->idns_name = NULL; 87 1.2.2.2 joerg idns->idns_namelen = 0; 88 1.2.2.2 joerg softd->ipf_p_dns_list = idns->idns_next; 89 1.2.2.2 joerg KFREE(idns); 90 1.2.2.2 joerg } 91 1.2.2.2 joerg RW_DESTROY(&softd->ipf_p_dns_rwlock); 92 1.2.2.2 joerg 93 1.2.2.2 joerg KFREE(softd); 94 1.2.2.2 joerg } 95 1.2.2.2 joerg 96 1.2.2.2 joerg 97 1.2.2.2 joerg int 98 1.2.2.2 joerg ipf_p_dns_ctl(ipf_main_softc_t *softc, void *arg, ap_ctl_t *ctl) 99 1.2.2.2 joerg { 100 1.2.2.2 joerg ipf_dns_softc_t *softd = arg; 101 1.2.2.2 joerg ipf_dns_filter_t *tmp, *idns, **idnsp; 102 1.2.2.2 joerg int error = 0; 103 1.2.2.2 joerg 104 1.2.2.2 joerg /* 105 1.2.2.2 joerg * To make locking easier. 106 1.2.2.2 joerg */ 107 1.2.2.2 joerg KMALLOC(tmp, ipf_dns_filter_t *); 108 1.2.2.2 joerg 109 1.2.2.2 joerg WRITE_ENTER(&softd->ipf_p_dns_rwlock); 110 1.2.2.2 joerg for (idnsp = &softd->ipf_p_dns_list; (idns = *idnsp) != NULL; 111 1.2.2.2 joerg idnsp = &idns->idns_next) { 112 1.2.2.2 joerg if (idns->idns_namelen != ctl->apc_dsize) 113 1.2.2.2 joerg continue; 114 1.2.2.2 joerg if (!strncmp(ctl->apc_data, idns->idns_name, 115 1.2.2.2 joerg idns->idns_namelen)) 116 1.2.2.2 joerg break; 117 1.2.2.2 joerg } 118 1.2.2.2 joerg 119 1.2.2.2 joerg switch (ctl->apc_cmd) 120 1.2.2.2 joerg { 121 1.2.2.2 joerg case APC_CMD_DEL : 122 1.2.2.2 joerg if (idns == NULL) { 123 1.2.2.2 joerg IPFERROR(80006); 124 1.2.2.2 joerg error = ESRCH; 125 1.2.2.2 joerg break; 126 1.2.2.2 joerg } 127 1.2.2.2 joerg *idnsp = idns->idns_next; 128 1.2.2.2 joerg idns->idns_next = NULL; 129 1.2.2.2 joerg KFREES(idns->idns_name, idns->idns_namelen); 130 1.2.2.2 joerg idns->idns_name = NULL; 131 1.2.2.2 joerg idns->idns_namelen = 0; 132 1.2.2.2 joerg KFREE(idns); 133 1.2.2.2 joerg break; 134 1.2.2.2 joerg case APC_CMD_ADD : 135 1.2.2.2 joerg if (idns != NULL) { 136 1.2.2.2 joerg IPFERROR(80007); 137 1.2.2.2 joerg error = EEXIST; 138 1.2.2.2 joerg break; 139 1.2.2.2 joerg } 140 1.2.2.2 joerg if (tmp == NULL) { 141 1.2.2.2 joerg IPFERROR(80008); 142 1.2.2.2 joerg error = ENOMEM; 143 1.2.2.2 joerg break; 144 1.2.2.2 joerg } 145 1.2.2.2 joerg idns = tmp; 146 1.2.2.2 joerg tmp = NULL; 147 1.2.2.2 joerg idns->idns_namelen = ctl->apc_dsize; 148 1.2.2.2 joerg idns->idns_name = ctl->apc_data; 149 1.2.2.2 joerg idns->idns_pass = ctl->apc_arg; 150 1.2.2.2 joerg idns->idns_next = NULL; 151 1.2.2.2 joerg *idnsp = idns; 152 1.2.2.2 joerg ctl->apc_data = NULL; 153 1.2.2.2 joerg ctl->apc_dsize = 0; 154 1.2.2.2 joerg break; 155 1.2.2.2 joerg default : 156 1.2.2.2 joerg IPFERROR(80009); 157 1.2.2.2 joerg error = EINVAL; 158 1.2.2.2 joerg break; 159 1.2.2.2 joerg } 160 1.2.2.2 joerg RWLOCK_EXIT(&softd->ipf_p_dns_rwlock); 161 1.2.2.2 joerg 162 1.2.2.2 joerg if (tmp != NULL) { 163 1.2.2.2 joerg KFREE(tmp); 164 1.2.2.2 joerg tmp = NULL; 165 1.2.2.2 joerg } 166 1.2.2.2 joerg 167 1.2.2.2 joerg return error; 168 1.2.2.2 joerg } 169 1.2.2.2 joerg 170 1.2.2.2 joerg 171 1.2.2.2 joerg /* ARGSUSED */ 172 1.2.2.2 joerg int 173 1.2.2.2 joerg ipf_p_dns_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) 174 1.2.2.2 joerg { 175 1.2.2.2 joerg dnsinfo_t *di; 176 1.2.2.2 joerg int dlen; 177 1.2.2.2 joerg 178 1.2.2.2 joerg dlen = fin->fin_dlen - sizeof(udphdr_t); 179 1.2.2.2 joerg if (dlen < sizeof(ipf_dns_hdr_t)) { 180 1.2.2.2 joerg /* 181 1.2.2.2 joerg * No real DNS packet is smaller than that. 182 1.2.2.2 joerg */ 183 1.2.2.2 joerg return -1; 184 1.2.2.2 joerg } 185 1.2.2.2 joerg 186 1.2.2.2 joerg aps->aps_psiz = sizeof(dnsinfo_t); 187 1.2.2.2 joerg KMALLOCS(di, dnsinfo_t *, sizeof(dnsinfo_t)); 188 1.2.2.2 joerg if (di == NULL) { 189 1.2.2.2 joerg printf("ipf_dns_new:KMALLOCS(%zu) failed\n", sizeof(*di)); 190 1.2.2.2 joerg return -1; 191 1.2.2.2 joerg } 192 1.2.2.2 joerg 193 1.2.2.2 joerg MUTEX_INIT(&di->dnsi_lock, "dns lock"); 194 1.2.2.2 joerg 195 1.2.2.2 joerg aps->aps_data = di; 196 1.2.2.2 joerg 197 1.2.2.2 joerg dlen = fin->fin_dlen - sizeof(udphdr_t); 198 1.2.2.2 joerg COPYDATA(fin->fin_m, fin->fin_hlen + sizeof(udphdr_t), 199 1.2.2.2 joerg MIN(dlen, sizeof(di->dnsi_buffer)), di->dnsi_buffer); 200 1.2.2.2 joerg di->dnsi_id = (di->dnsi_buffer[0] << 8) | di->dnsi_buffer[1]; 201 1.2.2.2 joerg return 0; 202 1.2.2.2 joerg } 203 1.2.2.2 joerg 204 1.2.2.2 joerg 205 1.2.2.2 joerg /* ARGSUSED */ 206 1.2.2.2 joerg int 207 1.2.2.2 joerg ipf_p_dns_del(ipf_main_softc_t *softc, ap_session_t *aps) 208 1.2.2.2 joerg { 209 1.2.2.2 joerg #ifdef USE_MUTEXES 210 1.2.2.2 joerg dnsinfo_t *di = aps->aps_data; 211 1.2.2.2 joerg 212 1.2.2.2 joerg MUTEX_DESTROY(&di->dnsi_lock); 213 1.2.2.2 joerg #endif 214 1.2.2.2 joerg KFREES(aps->aps_data, aps->aps_psiz); 215 1.2.2.2 joerg aps->aps_data = NULL; 216 1.2.2.2 joerg aps->aps_psiz = 0; 217 1.2.2.2 joerg return 0; 218 1.2.2.2 joerg } 219 1.2.2.2 joerg 220 1.2.2.2 joerg 221 1.2.2.2 joerg /* 222 1.2.2.2 joerg * Tries to match the base string (in our ACL) with the query from a packet. 223 1.2.2.2 joerg */ 224 1.2.2.2 joerg int 225 1.2.2.2 joerg ipf_p_dns_match_names(ipf_dns_filter_t *idns, char *query, int qlen) 226 1.2.2.2 joerg { 227 1.2.2.2 joerg int blen; 228 1.2.2.2 joerg char *base; 229 1.2.2.2 joerg 230 1.2.2.2 joerg blen = idns->idns_namelen; 231 1.2.2.2 joerg base = idns->idns_name; 232 1.2.2.2 joerg 233 1.2.2.2 joerg if (blen > qlen) 234 1.2.2.2 joerg return 1; 235 1.2.2.2 joerg 236 1.2.2.2 joerg if (blen == qlen) 237 1.2.2.2 joerg return strncasecmp(base, query, qlen); 238 1.2.2.2 joerg 239 1.2.2.2 joerg /* 240 1.2.2.2 joerg * If the base string string is shorter than the query, allow the 241 1.2.2.2 joerg * tail of the base to match the same length tail of the query *if*: 242 1.2.2.2 joerg * - the base string starts with a '*' (*cnn.com) 243 1.2.2.2 joerg * - the base string represents a domain (.cnn.com) 244 1.2.2.2 joerg * as otherwise it would not be possible to block just "cnn.com" 245 1.2.2.2 joerg * without also impacting "foocnn.com", etc. 246 1.2.2.2 joerg */ 247 1.2.2.2 joerg if (*base == '*') { 248 1.2.2.2 joerg base++; 249 1.2.2.2 joerg blen--; 250 1.2.2.2 joerg } else if (*base != '.') 251 1.2.2.2 joerg return 1; 252 1.2.2.2 joerg 253 1.2.2.2 joerg return strncasecmp(base, query + qlen - blen, blen); 254 1.2.2.2 joerg } 255 1.2.2.2 joerg 256 1.2.2.2 joerg 257 1.2.2.2 joerg int 258 1.2.2.2 joerg ipf_p_dns_get_name(ipf_dns_softc_t *softd, char *start, int len, char *buffer, 259 1.2.2.2 joerg int buflen) 260 1.2.2.2 joerg { 261 1.2.2.2 joerg char *s, *t, clen; 262 1.2.2.2 joerg int slen, blen; 263 1.2.2.2 joerg 264 1.2.2.2 joerg s = start; 265 1.2.2.2 joerg t = buffer; 266 1.2.2.2 joerg slen = len; 267 1.2.2.2 joerg blen = buflen - 1; /* Always make room for trailing \0 */ 268 1.2.2.2 joerg 269 1.2.2.2 joerg while (*s != '\0') { 270 1.2.2.2 joerg clen = *s; 271 1.2.2.2 joerg if ((clen & 0xc0) == 0xc0) { /* Doesn't do compression */ 272 1.2.2.2 joerg softd->ipf_p_dns_compress++; 273 1.2.2.2 joerg return 0; 274 1.2.2.2 joerg } 275 1.2.2.2 joerg if (clen > slen) { 276 1.2.2.2 joerg softd->ipf_p_dns_toolong++; 277 1.2.2.2 joerg return 0; /* Does the name run off the end? */ 278 1.2.2.2 joerg } 279 1.2.2.2 joerg if ((clen + 1) > blen) { 280 1.2.2.2 joerg softd->ipf_p_dns_nospace++; 281 1.2.2.2 joerg return 0; /* Enough room for name+.? */ 282 1.2.2.2 joerg } 283 1.2.2.2 joerg s++; 284 1.2.2.2 joerg bcopy(s, t, clen); 285 1.2.2.2 joerg t += clen; 286 1.2.2.2 joerg s += clen; 287 1.2.2.2 joerg *t++ = '.'; 288 1.2.2.2 joerg slen -= clen; 289 1.2.2.2 joerg blen -= (clen + 1); 290 1.2.2.2 joerg } 291 1.2.2.2 joerg 292 1.2.2.2 joerg *(t - 1) = '\0'; 293 1.2.2.2 joerg return s - start; 294 1.2.2.2 joerg } 295 1.2.2.2 joerg 296 1.2.2.2 joerg 297 1.2.2.2 joerg int 298 1.2.2.2 joerg ipf_p_dns_allow_query(ipf_dns_softc_t *softd, dnsinfo_t *dnsi) 299 1.2.2.2 joerg { 300 1.2.2.2 joerg ipf_dns_filter_t *idns; 301 1.2.2.2 joerg int len; 302 1.2.2.2 joerg 303 1.2.2.2 joerg len = strlen(dnsi->dnsi_buffer); 304 1.2.2.2 joerg 305 1.2.2.2 joerg for (idns = softd->ipf_p_dns_list; idns != NULL; idns = idns->idns_next) 306 1.2.2.2 joerg if (ipf_p_dns_match_names(idns, dnsi->dnsi_buffer, len) == 0) 307 1.2.2.2 joerg return idns->idns_pass; 308 1.2.2.2 joerg return 0; 309 1.2.2.2 joerg } 310 1.2.2.2 joerg 311 1.2.2.2 joerg 312 1.2.2.2 joerg /* ARGSUSED */ 313 1.2.2.2 joerg int 314 1.2.2.2 joerg ipf_p_dns_inout(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) 315 1.2.2.2 joerg { 316 1.2.2.2 joerg ipf_dns_softc_t *softd = arg; 317 1.2.2.2 joerg ipf_dns_hdr_t *dns; 318 1.2.2.2 joerg dnsinfo_t *di; 319 1.2.2.2 joerg char *data; 320 1.2.2.2 joerg int dlen, q, rc = 0; 321 1.2.2.2 joerg 322 1.2.2.2 joerg if (fin->fin_dlen < sizeof(*dns)) 323 1.2.2.2 joerg return APR_ERR(1); 324 1.2.2.2 joerg 325 1.2.2.2 joerg dns = (ipf_dns_hdr_t *)((char *)fin->fin_dp + sizeof(udphdr_t)); 326 1.2.2.2 joerg 327 1.2.2.2 joerg q = dns->dns_qdcount; 328 1.2.2.2 joerg 329 1.2.2.2 joerg data = (char *)(dns + 1); 330 1.2.2.2 joerg dlen = fin->fin_dlen - sizeof(*dns) - sizeof(udphdr_t); 331 1.2.2.2 joerg 332 1.2.2.2 joerg di = aps->aps_data; 333 1.2.2.2 joerg 334 1.2.2.2 joerg READ_ENTER(&softd->ipf_p_dns_rwlock); 335 1.2.2.2 joerg MUTEX_ENTER(&di->dnsi_lock); 336 1.2.2.2 joerg 337 1.2.2.2 joerg for (; (dlen > 0) && (q > 0); q--) { 338 1.2.2.2 joerg int len; 339 1.2.2.2 joerg 340 1.2.2.2 joerg len = ipf_p_dns_get_name(softd, data, dlen, di->dnsi_buffer, 341 1.2.2.2 joerg sizeof(di->dnsi_buffer)); 342 1.2.2.2 joerg if (len == 0) { 343 1.2.2.2 joerg rc = 1; 344 1.2.2.2 joerg break; 345 1.2.2.2 joerg } 346 1.2.2.2 joerg rc = ipf_p_dns_allow_query(softd, di); 347 1.2.2.2 joerg if (rc != 0) 348 1.2.2.2 joerg break; 349 1.2.2.2 joerg data += len; 350 1.2.2.2 joerg dlen -= len; 351 1.2.2.2 joerg } 352 1.2.2.2 joerg MUTEX_EXIT(&di->dnsi_lock); 353 1.2.2.2 joerg RWLOCK_EXIT(&softd->ipf_p_dns_rwlock); 354 1.2.2.2 joerg 355 1.2.2.2 joerg return APR_ERR(rc); 356 1.2.2.2 joerg } 357 1.2.2.2 joerg 358 1.2.2.2 joerg 359 1.2.2.2 joerg /* ARGSUSED */ 360 1.2.2.2 joerg int 361 1.2.2.2 joerg ipf_p_dns_match(fr_info_t *fin, ap_session_t *aps, nat_t *nat) 362 1.2.2.2 joerg { 363 1.2.2.2 joerg dnsinfo_t *di = aps->aps_data; 364 1.2.2.2 joerg ipf_dns_hdr_t *dnh; 365 1.2.2.2 joerg 366 1.2.2.2 joerg if ((fin->fin_dlen < sizeof(u_short)) || (fin->fin_flx & FI_FRAG)) 367 1.2.2.2 joerg return -1; 368 1.2.2.2 joerg 369 1.2.2.2 joerg dnh = (ipf_dns_hdr_t *)((char *)fin->fin_dp + sizeof(udphdr_t)); 370 1.2.2.2 joerg if (((dnh->dns_id[0] << 8) | dnh->dns_id[1]) != di->dnsi_id) 371 1.2.2.2 joerg return -1; 372 1.2.2.2 joerg return 0; 373 1.2.2.2 joerg } 374
Indexes created Wed Oct 29 03:09:52 GMT 2025