1 /* $OpenBSD: if_pflog.c,v 1.74 2016/04/29 08:55:03 krw Exp $ */ 2 /* 3 * The authors of this code are John Ioannidis (ji@tla.org), 4 * Angelos D. Keromytis (kermit@csd.uch.gr) and 5 * Niels Provos (provos@physnet.uni-hamburg.de). 6 * 7 * This code was written by John Ioannidis for BSD/OS in Athens, Greece, 8 * in November 1995. 9 * 10 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 11 * by Angelos D. Keromytis. 12 * 13 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 14 * and Niels Provos. 15 * 16 * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis 17 * and Niels Provos. 18 * Copyright (c) 2001, Angelos D. Keromytis, Niels Provos. 19 * Copyright (c) 2002 - 2010 Henning Brauer 20 * 21 * Permission to use, copy, and modify this software with or without fee 22 * is hereby granted, provided that this entire notice is included in 23 * all copies of any software which is or includes a copy or 24 * modification of this software. 25 * You may use this code under the GNU public license if you so wish. Please 26 * contribute changes back to the authors under this freer than GPL license 27 * so that we may further the use of strong encryption without limitations to 28 * all. 29 * 30 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 31 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 32 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 33 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 34 * PURPOSE. 35 */ 36 37 #include "bpfilter.h" 38 #include "pflog.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/mbuf.h> 43 #include <sys/proc.h> 44 #include <sys/socket.h> 45 #include <sys/stdint.h> 46 #include <sys/ioctl.h> 47 48 #include <net/if.h> 49 #include <net/if_var.h> 50 #include <net/if_types.h> 51 #include <net/bpf.h> 52 53 #include <netinet/in.h> 54 #include <netinet/ip.h> 55 #include <netinet/tcp.h> 56 #include <netinet/udp.h> 57 #include <netinet/ip_icmp.h> 58 59 #ifdef INET6 60 #include <netinet/ip6.h> 61 #include <netinet/icmp6.h> 62 #endif /* INET6 */ 63 64 #include <net/pfvar.h> 65 #include <net/if_pflog.h> 66 67 #define PFLOGMTU (32768 + MHLEN + MLEN) 68 69 #ifdef PFLOGDEBUG 70 #define DPRINTF(x) do { if (pflogdebug) printf x ; } while (0) 71 #else 72 #define DPRINTF(x) 73 #endif 74 75 void pflogattach(int); 76 int pflogifs_resize(size_t); 77 int pflogoutput(struct ifnet *, struct mbuf *, struct sockaddr *, 78 struct rtentry *); 79 int pflogioctl(struct ifnet *, u_long, caddr_t); 80 void pflogstart(struct ifnet *); 81 int pflog_clone_create(struct if_clone *, int); 82 int pflog_clone_destroy(struct ifnet *); 83 void pflog_bpfcopy(const void *, void *, size_t); 84 85 LIST_HEAD(, pflog_softc) pflogif_list; 86 struct if_clone pflog_cloner = 87 IF_CLONE_INITIALIZER("pflog", pflog_clone_create, pflog_clone_destroy); 88 89 int npflogifs = 0; 90 struct ifnet **pflogifs = NULL; /* for fast access */ 91 struct mbuf *pflog_mhdr = NULL, *pflog_mptr = NULL; 92 93 void 94 pflogattach(int npflog) 95 { 96 LIST_INIT(&pflogif_list); 97 if (pflog_mhdr == NULL) 98 if ((pflog_mhdr = m_get(M_DONTWAIT, MT_HEADER)) == NULL) 99 panic("pflogattach: no mbuf"); 100 if (pflog_mptr == NULL) 101 if ((pflog_mptr = m_get(M_DONTWAIT, MT_DATA)) == NULL) 102 panic("pflogattach: no mbuf"); 103 if_clone_attach(&pflog_cloner); 104 } 105 106 int 107 pflogifs_resize(size_t n) 108 { 109 struct ifnet **p; 110 int i; 111 112 if (n > SIZE_MAX / sizeof(*p)) 113 return (EINVAL); 114 if (n == 0) 115 p = NULL; 116 else 117 if ((p = mallocarray(n, sizeof(*p), M_DEVBUF, 118 M_NOWAIT|M_ZERO)) == NULL) 119 return (ENOMEM); 120 for (i = 0; i < n; i++) 121 if (i < npflogifs) 122 p[i] = pflogifs[i]; 123 else 124 p[i] = NULL; 125 126 if (pflogifs) 127 free(pflogifs, M_DEVBUF, 0); 128 pflogifs = p; 129 npflogifs = n; 130 return (0); 131 } 132 133 int 134 pflog_clone_create(struct if_clone *ifc, int unit) 135 { 136 struct ifnet *ifp; 137 struct pflog_softc *pflogif; 138 int s; 139 140 if ((pflogif = malloc(sizeof(*pflogif), 141 M_DEVBUF, M_NOWAIT|M_ZERO)) == NULL) 142 return (ENOMEM); 143 144 pflogif->sc_unit = unit; 145 ifp = &pflogif->sc_if; 146 snprintf(ifp->if_xname, sizeof ifp->if_xname, "pflog%d", unit); 147 ifp->if_softc = pflogif; 148 ifp->if_mtu = PFLOGMTU; 149 ifp->if_ioctl = pflogioctl; 150 ifp->if_output = pflogoutput; 151 ifp->if_start = pflogstart; 152 ifp->if_type = IFT_PFLOG; 153 IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN); 154 ifp->if_hdrlen = PFLOG_HDRLEN; 155 if_attach(ifp); 156 if_alloc_sadl(ifp); 157 158 #if NBPFILTER > 0 159 bpfattach(&pflogif->sc_if.if_bpf, ifp, DLT_PFLOG, PFLOG_HDRLEN); 160 #endif 161 162 s = splnet(); 163 LIST_INSERT_HEAD(&pflogif_list, pflogif, sc_list); 164 if (unit + 1 > npflogifs && pflogifs_resize(unit + 1) != 0) { 165 splx(s); 166 return (ENOMEM); 167 } 168 pflogifs[unit] = ifp; 169 splx(s); 170 171 return (0); 172 } 173 174 int 175 pflog_clone_destroy(struct ifnet *ifp) 176 { 177 struct pflog_softc *pflogif = ifp->if_softc; 178 int s, i; 179 180 s = splnet(); 181 pflogifs[pflogif->sc_unit] = NULL; 182 LIST_REMOVE(pflogif, sc_list); 183 184 for (i = npflogifs; i > 0 && pflogifs[i - 1] == NULL; i--) 185 ; /* nothing */ 186 if (i < npflogifs) 187 pflogifs_resize(i); /* error harmless here */ 188 splx(s); 189 190 if_detach(ifp); 191 free(pflogif, M_DEVBUF, 0); 192 return (0); 193 } 194 195 /* 196 * Start output on the pflog interface. 197 */ 198 void 199 pflogstart(struct ifnet *ifp) 200 { 201 IFQ_PURGE(&ifp->if_snd); 202 } 203 204 int 205 pflogoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 206 struct rtentry *rt) 207 { 208 m_freem(m); /* drop packet */ 209 return (EAFNOSUPPORT); 210 } 211 212 int 213 pflogioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 214 { 215 switch (cmd) { 216 case SIOCSIFFLAGS: 217 if (ifp->if_flags & IFF_UP) 218 ifp->if_flags |= IFF_RUNNING; 219 else 220 ifp->if_flags &= ~IFF_RUNNING; 221 break; 222 default: 223 return (ENOTTY); 224 } 225 226 return (0); 227 } 228 229 int 230 pflog_packet(struct pf_pdesc *pd, u_int8_t reason, struct pf_rule *rm, 231 struct pf_rule *am, struct pf_ruleset *ruleset, struct pf_rule *trigger) 232 { 233 #if NBPFILTER > 0 234 struct ifnet *ifn; 235 struct pfloghdr hdr; 236 237 if (rm == NULL || pd == NULL || pd->kif == NULL || pd->m == NULL) 238 return (-1); 239 if (trigger == NULL) 240 trigger = rm; 241 242 if (trigger->logif >= npflogifs || (ifn = pflogifs[trigger->logif]) == 243 NULL || !ifn->if_bpf) 244 return (0); 245 246 bzero(&hdr, sizeof(hdr)); 247 hdr.length = PFLOG_REAL_HDRLEN; 248 hdr.action = rm->action; 249 hdr.reason = reason; 250 memcpy(hdr.ifname, pd->kif->pfik_name, sizeof(hdr.ifname)); 251 252 if (am == NULL) { 253 hdr.rulenr = htonl(rm->nr); 254 hdr.subrulenr = -1; 255 } else { 256 hdr.rulenr = htonl(am->nr); 257 hdr.subrulenr = htonl(rm->nr); 258 if (ruleset != NULL && ruleset->anchor != NULL) 259 strlcpy(hdr.ruleset, ruleset->anchor->name, 260 sizeof(hdr.ruleset)); 261 } 262 if (trigger->log & PF_LOG_SOCKET_LOOKUP && !pd->lookup.done) 263 pd->lookup.done = pf_socket_lookup(pd); 264 if (pd->lookup.done > 0) { 265 hdr.uid = pd->lookup.uid; 266 hdr.pid = pd->lookup.pid; 267 } else { 268 hdr.uid = UID_MAX; 269 hdr.pid = NO_PID; 270 } 271 hdr.rule_uid = rm->cuid; 272 hdr.rule_pid = rm->cpid; 273 hdr.dir = pd->dir; 274 275 PF_ACPY(&hdr.saddr, &pd->nsaddr, pd->naf); 276 PF_ACPY(&hdr.daddr, &pd->ndaddr, pd->naf); 277 hdr.af = pd->af; 278 hdr.naf = pd->naf; 279 hdr.sport = pd->nsport; 280 hdr.dport = pd->ndport; 281 282 ifn->if_opackets++; 283 ifn->if_obytes += pd->m->m_pkthdr.len; 284 285 bpf_mtap_hdr(ifn->if_bpf, (caddr_t)&hdr, PFLOG_HDRLEN, pd->m, 286 BPF_DIRECTION_OUT, pflog_bpfcopy); 287 #endif 288 289 return (0); 290 } 291 292 void 293 pflog_bpfcopy(const void *src_arg, void *dst_arg, size_t len) 294 { 295 struct mbuf *m, *mp, *mhdr, *mptr; 296 struct pfloghdr *pfloghdr; 297 u_int count; 298 u_char *dst, *mdst; 299 int afto, hlen, mlen, off; 300 union pf_headers { 301 struct tcphdr tcp; 302 struct udphdr udp; 303 struct icmp icmp; 304 #ifdef INET6 305 struct icmp6_hdr icmp6; 306 struct mld_hdr mld; 307 struct nd_neighbor_solicit nd_ns; 308 #endif /* INET6 */ 309 } pdhdrs; 310 311 struct pf_pdesc pd; 312 struct pf_addr osaddr, odaddr; 313 u_int16_t osport = 0, odport = 0; 314 u_int8_t proto = 0; 315 316 m = (struct mbuf *)src_arg; 317 dst = dst_arg; 318 319 mhdr = pflog_mhdr; 320 mptr = pflog_mptr; 321 322 if (m == NULL) 323 panic("pflog_bpfcopy got no mbuf"); 324 325 /* first mbuf holds struct pfloghdr */ 326 pfloghdr = mtod(m, struct pfloghdr *); 327 afto = pfloghdr->af != pfloghdr->naf; 328 count = min(m->m_len, len); 329 bcopy(pfloghdr, dst, count); 330 pfloghdr = (struct pfloghdr *)dst; 331 dst += count; 332 len -= count; 333 m = m->m_next; 334 335 if (len <= 0) 336 return; 337 338 /* second mbuf is pkthdr */ 339 if (m == NULL) 340 panic("no second mbuf"); 341 342 /* 343 * temporary mbuf will hold an ip/ip6 header and 8 bytes 344 * of the protocol header 345 */ 346 m_inithdr(mhdr); 347 mhdr->m_len = 0; /* XXX not done in m_inithdr() */ 348 349 #ifdef INET6 350 /* offset for a new header */ 351 if (afto && pfloghdr->af == AF_INET) 352 mhdr->m_data += sizeof(struct ip6_hdr) - 353 sizeof(struct ip); 354 #endif /* INET6 */ 355 356 mdst = mtod(mhdr, char *); 357 switch (pfloghdr->af) { 358 case AF_INET: { 359 struct ip *h; 360 361 if (m->m_pkthdr.len < sizeof(*h)) 362 goto copy; 363 m_copydata(m, 0, sizeof(*h), mdst); 364 h = (struct ip *)mdst; 365 hlen = h->ip_hl << 2; 366 if (hlen > sizeof(*h) && (m->m_pkthdr.len >= hlen)) 367 m_copydata(m, sizeof(*h), hlen - sizeof(*h), 368 mdst + sizeof(*h)); 369 break; 370 } 371 #ifdef INET6 372 case AF_INET6: { 373 struct ip6_hdr *h; 374 375 if (m->m_pkthdr.len < sizeof(*h)) 376 goto copy; 377 hlen = sizeof(struct ip6_hdr); 378 m_copydata(m, 0, hlen, mdst); 379 h = (struct ip6_hdr *)mdst; 380 proto = h->ip6_nxt; 381 break; 382 } 383 #endif /* INET6 */ 384 default: 385 /* shouldn't happen ever :-) */ 386 goto copy; 387 } 388 389 if (m->m_pkthdr.len < hlen + 8 && proto != IPPROTO_NONE) 390 goto copy; 391 else if (proto != IPPROTO_NONE) { 392 /* copy 8 bytes of the protocol header */ 393 m_copydata(m, hlen, 8, mdst + hlen); 394 hlen += 8; 395 } 396 397 mhdr->m_len += hlen; 398 mhdr->m_pkthdr.len = mhdr->m_len; 399 400 /* create a chain mhdr -> mptr, mptr->m_data = (m->m_data+hlen) */ 401 mp = m_getptr(m, hlen, &off); 402 if (mp != NULL) { 403 bcopy(mp, mptr, sizeof(*mptr)); 404 mptr->m_data += off; 405 mptr->m_len -= off; 406 mptr->m_flags &= ~M_PKTHDR; 407 mhdr->m_next = mptr; 408 mhdr->m_pkthdr.len += m->m_pkthdr.len - hlen; 409 } 410 411 /* 412 * Rewrite addresses if needed. Reason pointer must be NULL to avoid 413 * counting the packet here again. 414 */ 415 if (pf_setup_pdesc(&pd, &pdhdrs, pfloghdr->af, pfloghdr->dir, NULL, 416 mhdr, NULL) != PF_PASS) 417 goto copy; 418 pd.naf = pfloghdr->naf; 419 420 PF_ACPY(&osaddr, pd.src, pd.af); 421 PF_ACPY(&odaddr, pd.dst, pd.af); 422 if (pd.sport) 423 osport = *pd.sport; 424 if (pd.dport) 425 odport = *pd.dport; 426 427 if (pd.virtual_proto != PF_VPROTO_FRAGMENT && 428 (pfloghdr->rewritten = pf_translate(&pd, &pfloghdr->saddr, 429 pfloghdr->sport, &pfloghdr->daddr, pfloghdr->dport, 0, 430 pfloghdr->dir))) { 431 m_copyback(pd.m, pd.off, min(pd.m->m_len - pd.off, pd.hdrlen), 432 pd.hdr.any, M_NOWAIT); 433 #ifdef INET6 434 if (afto) { 435 PF_ACPY(&pd.nsaddr, &pfloghdr->saddr, pd.naf); 436 PF_ACPY(&pd.ndaddr, &pfloghdr->daddr, pd.naf); 437 } 438 #endif /* INET6 */ 439 PF_ACPY(&pfloghdr->saddr, &osaddr, pd.af); 440 PF_ACPY(&pfloghdr->daddr, &odaddr, pd.af); 441 pfloghdr->sport = osport; 442 pfloghdr->dport = odport; 443 } 444 445 pd.tot_len = min(pd.tot_len, len); 446 pd.tot_len -= pd.m->m_data - pd.m->m_pktdat; 447 448 #ifdef INET6 449 if (afto && pfloghdr->rewritten) 450 pf_translate_af(&pd); 451 #endif /* INET6 */ 452 453 m = pd.m; 454 copy: 455 mlen = min(m->m_pkthdr.len, len); 456 m_copydata(m, 0, mlen, dst); 457 len -= mlen; 458 if (len > 0) 459 bzero(dst + mlen, len); 460 } 461