1 /* 2 * WPA Supplicant - Layer2 packet handling with Linux packet sockets 3 * Copyright (c) 2003-2015, Jouni Malinen <j@w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 #include <sys/ioctl.h> 11 #include <netpacket/packet.h> 12 #include <net/if.h> 13 #include <linux/filter.h> 14 15 #include "common.h" 16 #include "eloop.h" 17 #include "crypto/sha1.h" 18 #include "crypto/crypto.h" 19 #include "l2_packet.h" 20 21 22 struct l2_packet_data { 23 int fd; /* packet socket for EAPOL frames */ 24 char ifname[IFNAMSIZ + 1]; 25 int ifindex; 26 u8 own_addr[ETH_ALEN]; 27 void (*rx_callback)(void *ctx, const u8 *src_addr, 28 const u8 *buf, size_t len); 29 void *rx_callback_ctx; 30 int l2_hdr; /* whether to include layer 2 (Ethernet) header data 31 * buffers */ 32 33 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 34 /* For working around Linux packet socket behavior and regression. */ 35 int fd_br_rx; 36 int last_from_br, last_from_br_prev; 37 u8 last_hash[SHA1_MAC_LEN]; 38 u8 last_hash_prev[SHA1_MAC_LEN]; 39 unsigned int num_rx_br; 40 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 41 }; 42 43 /* Generated by 'sudo tcpdump -s 3000 -dd greater 278 and ip and udp and 44 * src port bootps and dst port bootpc' 45 */ 46 static struct sock_filter dhcp_sock_filter_insns[] = { 47 { 0x80, 0, 0, 0x00000000 }, 48 { 0x35, 0, 12, 0x00000116 }, 49 { 0x28, 0, 0, 0x0000000c }, 50 { 0x15, 0, 10, 0x00000800 }, 51 { 0x30, 0, 0, 0x00000017 }, 52 { 0x15, 0, 8, 0x00000011 }, 53 { 0x28, 0, 0, 0x00000014 }, 54 { 0x45, 6, 0, 0x00001fff }, 55 { 0xb1, 0, 0, 0x0000000e }, 56 { 0x48, 0, 0, 0x0000000e }, 57 { 0x15, 0, 3, 0x00000043 }, 58 { 0x48, 0, 0, 0x00000010 }, 59 { 0x15, 0, 1, 0x00000044 }, 60 { 0x6, 0, 0, 0x00000bb8 }, 61 { 0x6, 0, 0, 0x00000000 }, 62 }; 63 64 static const struct sock_fprog dhcp_sock_filter = { 65 .len = ARRAY_SIZE(dhcp_sock_filter_insns), 66 .filter = dhcp_sock_filter_insns, 67 }; 68 69 70 /* Generated by 'sudo tcpdump -dd -s 1500 multicast and ip6[6]=58' */ 71 static struct sock_filter ndisc_sock_filter_insns[] = { 72 { 0x30, 0, 0, 0x00000000 }, 73 { 0x45, 0, 5, 0x00000001 }, 74 { 0x28, 0, 0, 0x0000000c }, 75 { 0x15, 0, 3, 0x000086dd }, 76 { 0x30, 0, 0, 0x00000014 }, 77 { 0x15, 0, 1, 0x0000003a }, 78 { 0x6, 0, 0, 0x000005dc }, 79 { 0x6, 0, 0, 0x00000000 }, 80 }; 81 82 static const struct sock_fprog ndisc_sock_filter = { 83 .len = ARRAY_SIZE(ndisc_sock_filter_insns), 84 .filter = ndisc_sock_filter_insns, 85 }; 86 87 /* drop packet if skb->pkt_type is PACKET_OTHERHOST (0x03). Generated by: 88 * $ bpfc - <<EOF 89 * > ldb #type 90 * > jeq #0x03, drop 91 * > pass: ret #-1 92 * > drop: ret #0 93 * > EOF 94 */ 95 static struct sock_filter pkt_type_filter_insns[] = { 96 { 0x30, 0, 0, 0xfffff004 }, 97 { 0x15, 1, 0, 0x00000003 }, 98 { 0x6, 0, 0, 0xffffffff }, 99 { 0x6, 0, 0, 0x00000000 }, 100 }; 101 102 static const struct sock_fprog pkt_type_sock_filter = { 103 .len = ARRAY_SIZE(pkt_type_filter_insns), 104 .filter = pkt_type_filter_insns, 105 }; 106 107 108 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr) 109 { 110 os_memcpy(addr, l2->own_addr, ETH_ALEN); 111 return 0; 112 } 113 114 115 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto, 116 const u8 *buf, size_t len) 117 { 118 int ret; 119 120 if (TEST_FAIL()) 121 return -1; 122 if (l2 == NULL) 123 return -1; 124 if (l2->l2_hdr) { 125 ret = send(l2->fd, buf, len, 0); 126 if (ret < 0) 127 wpa_printf(MSG_ERROR, "l2_packet_send - send: %s", 128 strerror(errno)); 129 } else { 130 struct sockaddr_ll ll; 131 os_memset(&ll, 0, sizeof(ll)); 132 ll.sll_family = AF_PACKET; 133 ll.sll_ifindex = l2->ifindex; 134 ll.sll_protocol = htons(proto); 135 ll.sll_halen = ETH_ALEN; 136 os_memcpy(ll.sll_addr, dst_addr, ETH_ALEN); 137 ret = sendto(l2->fd, buf, len, 0, (struct sockaddr *) &ll, 138 sizeof(ll)); 139 if (ret < 0) { 140 wpa_printf(MSG_ERROR, "l2_packet_send - sendto: %s", 141 strerror(errno)); 142 } 143 } 144 return ret; 145 } 146 147 148 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx) 149 { 150 struct l2_packet_data *l2 = eloop_ctx; 151 u8 buf[2300]; 152 int res; 153 struct sockaddr_ll ll; 154 socklen_t fromlen; 155 156 os_memset(&ll, 0, sizeof(ll)); 157 fromlen = sizeof(ll); 158 res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll, 159 &fromlen); 160 if (res < 0) { 161 wpa_printf(MSG_DEBUG, "l2_packet_receive - recvfrom: %s", 162 strerror(errno)); 163 return; 164 } 165 166 wpa_printf(MSG_DEBUG, "%s: src=" MACSTR " len=%d", 167 __func__, MAC2STR(ll.sll_addr), (int) res); 168 169 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 170 if (l2->fd_br_rx >= 0) { 171 u8 hash[SHA1_MAC_LEN]; 172 const u8 *addr[1]; 173 size_t len[1]; 174 175 /* 176 * Close the workaround socket if the kernel version seems to be 177 * able to deliver packets through the packet socket before 178 * authorization has been completed (in dormant state). 179 */ 180 if (l2->num_rx_br <= 1) { 181 wpa_printf(MSG_DEBUG, 182 "l2_packet_receive: Main packet socket for %s seems to have working RX - close workaround bridge socket", 183 l2->ifname); 184 eloop_unregister_read_sock(l2->fd_br_rx); 185 close(l2->fd_br_rx); 186 l2->fd_br_rx = -1; 187 } 188 189 addr[0] = buf; 190 len[0] = res; 191 sha1_vector(1, addr, len, hash); 192 if (l2->last_from_br && 193 os_memcmp(hash, l2->last_hash, SHA1_MAC_LEN) == 0) { 194 wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX", 195 __func__); 196 return; 197 } 198 if (l2->last_from_br_prev && 199 os_memcmp(hash, l2->last_hash_prev, SHA1_MAC_LEN) == 0) { 200 wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX(prev)", 201 __func__); 202 return; 203 } 204 os_memcpy(l2->last_hash_prev, l2->last_hash, SHA1_MAC_LEN); 205 l2->last_from_br_prev = l2->last_from_br; 206 os_memcpy(l2->last_hash, hash, SHA1_MAC_LEN); 207 } 208 209 l2->last_from_br = 0; 210 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 211 l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res); 212 } 213 214 215 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 216 static void l2_packet_receive_br(int sock, void *eloop_ctx, void *sock_ctx) 217 { 218 struct l2_packet_data *l2 = eloop_ctx; 219 u8 buf[2300]; 220 int res; 221 struct sockaddr_ll ll; 222 socklen_t fromlen; 223 u8 hash[SHA1_MAC_LEN]; 224 const u8 *addr[1]; 225 size_t len[1]; 226 227 l2->num_rx_br++; 228 os_memset(&ll, 0, sizeof(ll)); 229 fromlen = sizeof(ll); 230 res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll, 231 &fromlen); 232 if (res < 0) { 233 wpa_printf(MSG_DEBUG, "l2_packet_receive_br - recvfrom: %s", 234 strerror(errno)); 235 return; 236 } 237 238 wpa_printf(MSG_DEBUG, "%s: src=" MACSTR " len=%d", 239 __func__, MAC2STR(ll.sll_addr), (int) res); 240 241 if (os_memcmp(ll.sll_addr, l2->own_addr, ETH_ALEN) == 0) { 242 wpa_printf(MSG_DEBUG, "%s: Drop RX of own frame", __func__); 243 return; 244 } 245 246 addr[0] = buf; 247 len[0] = res; 248 sha1_vector(1, addr, len, hash); 249 if (!l2->last_from_br && 250 os_memcmp(hash, l2->last_hash, SHA1_MAC_LEN) == 0) { 251 wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX", __func__); 252 return; 253 } 254 if (!l2->last_from_br_prev && 255 os_memcmp(hash, l2->last_hash_prev, SHA1_MAC_LEN) == 0) { 256 wpa_printf(MSG_DEBUG, "%s: Drop duplicate RX(prev)", __func__); 257 return; 258 } 259 os_memcpy(l2->last_hash_prev, l2->last_hash, SHA1_MAC_LEN); 260 l2->last_from_br_prev = l2->last_from_br; 261 l2->last_from_br = 1; 262 os_memcpy(l2->last_hash, hash, SHA1_MAC_LEN); 263 l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res); 264 } 265 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 266 267 268 struct l2_packet_data * l2_packet_init( 269 const char *ifname, const u8 *own_addr, unsigned short protocol, 270 void (*rx_callback)(void *ctx, const u8 *src_addr, 271 const u8 *buf, size_t len), 272 void *rx_callback_ctx, int l2_hdr) 273 { 274 struct l2_packet_data *l2; 275 struct ifreq ifr; 276 struct sockaddr_ll ll; 277 278 l2 = os_zalloc(sizeof(struct l2_packet_data)); 279 if (l2 == NULL) 280 return NULL; 281 os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname)); 282 l2->rx_callback = rx_callback; 283 l2->rx_callback_ctx = rx_callback_ctx; 284 l2->l2_hdr = l2_hdr; 285 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 286 l2->fd_br_rx = -1; 287 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 288 289 l2->fd = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM, 290 htons(protocol)); 291 if (l2->fd < 0) { 292 wpa_printf(MSG_ERROR, "%s: socket(PF_PACKET): %s", 293 __func__, strerror(errno)); 294 os_free(l2); 295 return NULL; 296 } 297 os_memset(&ifr, 0, sizeof(ifr)); 298 os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name)); 299 if (ioctl(l2->fd, SIOCGIFINDEX, &ifr) < 0) { 300 wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFINDEX]: %s", 301 __func__, strerror(errno)); 302 close(l2->fd); 303 os_free(l2); 304 return NULL; 305 } 306 l2->ifindex = ifr.ifr_ifindex; 307 308 os_memset(&ll, 0, sizeof(ll)); 309 ll.sll_family = PF_PACKET; 310 ll.sll_ifindex = ifr.ifr_ifindex; 311 ll.sll_protocol = htons(protocol); 312 if (bind(l2->fd, (struct sockaddr *) &ll, sizeof(ll)) < 0) { 313 wpa_printf(MSG_ERROR, "%s: bind[PF_PACKET]: %s", 314 __func__, strerror(errno)); 315 close(l2->fd); 316 os_free(l2); 317 return NULL; 318 } 319 320 if (ioctl(l2->fd, SIOCGIFHWADDR, &ifr) < 0) { 321 wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFHWADDR]: %s", 322 __func__, strerror(errno)); 323 close(l2->fd); 324 os_free(l2); 325 return NULL; 326 } 327 os_memcpy(l2->own_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN); 328 329 eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL); 330 331 return l2; 332 } 333 334 335 struct l2_packet_data * l2_packet_init_bridge( 336 const char *br_ifname, const char *ifname, const u8 *own_addr, 337 unsigned short protocol, 338 void (*rx_callback)(void *ctx, const u8 *src_addr, 339 const u8 *buf, size_t len), 340 void *rx_callback_ctx, int l2_hdr) 341 { 342 struct l2_packet_data *l2; 343 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 344 struct sock_filter ethertype_sock_filter_insns[] = { 345 /* Load ethertype */ 346 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 2 * ETH_ALEN), 347 /* Jump over next statement if ethertype does not match */ 348 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, protocol, 0, 1), 349 /* Ethertype match - return all */ 350 BPF_STMT(BPF_RET | BPF_K, ~0), 351 /* No match - drop */ 352 BPF_STMT(BPF_RET | BPF_K, 0) 353 }; 354 const struct sock_fprog ethertype_sock_filter = { 355 .len = ARRAY_SIZE(ethertype_sock_filter_insns), 356 .filter = ethertype_sock_filter_insns, 357 }; 358 struct sockaddr_ll ll; 359 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 360 361 l2 = l2_packet_init(br_ifname, own_addr, protocol, rx_callback, 362 rx_callback_ctx, l2_hdr); 363 if (!l2) 364 return NULL; 365 366 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 367 /* 368 * The Linux packet socket behavior has changed over the years and there 369 * is an inconvenient regression in it that breaks RX for a specific 370 * protocol from interfaces in a bridge when that interface is not in 371 * fully operation state (i.e., when in station mode and not completed 372 * authorization). To work around this, register ETH_P_ALL version of 373 * the packet socket bound to the real netdev and use socket filter to 374 * match the ethertype value. This version is less efficient, but 375 * required for functionality with many kernel version. If the main 376 * packet socket is found to be working, this less efficient version 377 * gets closed automatically. 378 */ 379 380 l2->fd_br_rx = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM, 381 htons(ETH_P_ALL)); 382 if (l2->fd_br_rx < 0) { 383 wpa_printf(MSG_DEBUG, "%s: socket(PF_PACKET-fd_br_rx): %s", 384 __func__, strerror(errno)); 385 /* try to continue without the workaround RX socket */ 386 return l2; 387 } 388 389 os_memset(&ll, 0, sizeof(ll)); 390 ll.sll_family = PF_PACKET; 391 ll.sll_ifindex = if_nametoindex(ifname); 392 ll.sll_protocol = htons(ETH_P_ALL); 393 if (bind(l2->fd_br_rx, (struct sockaddr *) &ll, sizeof(ll)) < 0) { 394 wpa_printf(MSG_DEBUG, "%s: bind[PF_PACKET-fd_br_rx]: %s", 395 __func__, strerror(errno)); 396 /* try to continue without the workaround RX socket */ 397 close(l2->fd_br_rx); 398 l2->fd_br_rx = -1; 399 return l2; 400 } 401 402 if (setsockopt(l2->fd_br_rx, SOL_SOCKET, SO_ATTACH_FILTER, 403 ðertype_sock_filter, sizeof(struct sock_fprog))) { 404 wpa_printf(MSG_DEBUG, 405 "l2_packet_linux: setsockopt(SO_ATTACH_FILTER) failed: %s", 406 strerror(errno)); 407 /* try to continue without the workaround RX socket */ 408 close(l2->fd_br_rx); 409 l2->fd_br_rx = -1; 410 return l2; 411 } 412 413 eloop_register_read_sock(l2->fd_br_rx, l2_packet_receive_br, l2, NULL); 414 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 415 416 return l2; 417 } 418 419 420 void l2_packet_deinit(struct l2_packet_data *l2) 421 { 422 if (l2 == NULL) 423 return; 424 425 if (l2->fd >= 0) { 426 eloop_unregister_read_sock(l2->fd); 427 close(l2->fd); 428 } 429 430 #ifndef CONFIG_NO_LINUX_PACKET_SOCKET_WAR 431 if (l2->fd_br_rx >= 0) { 432 eloop_unregister_read_sock(l2->fd_br_rx); 433 close(l2->fd_br_rx); 434 } 435 #endif /* CONFIG_NO_LINUX_PACKET_SOCKET_WAR */ 436 437 os_free(l2); 438 } 439 440 441 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len) 442 { 443 int s; 444 struct ifreq ifr; 445 struct sockaddr_in *saddr; 446 size_t res; 447 448 s = socket(PF_INET, SOCK_DGRAM, 0); 449 if (s < 0) { 450 wpa_printf(MSG_ERROR, "%s: socket: %s", 451 __func__, strerror(errno)); 452 return -1; 453 } 454 os_memset(&ifr, 0, sizeof(ifr)); 455 os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name)); 456 if (ioctl(s, SIOCGIFADDR, &ifr) < 0) { 457 if (errno != EADDRNOTAVAIL) 458 wpa_printf(MSG_ERROR, "%s: ioctl[SIOCGIFADDR]: %s", 459 __func__, strerror(errno)); 460 close(s); 461 return -1; 462 } 463 close(s); 464 saddr = aliasing_hide_typecast(&ifr.ifr_addr, struct sockaddr_in); 465 if (saddr->sin_family != AF_INET) 466 return -1; 467 res = os_strlcpy(buf, inet_ntoa(saddr->sin_addr), len); 468 if (res >= len) 469 return -1; 470 return 0; 471 } 472 473 474 void l2_packet_notify_auth_start(struct l2_packet_data *l2) 475 { 476 } 477 478 479 int l2_packet_set_packet_filter(struct l2_packet_data *l2, 480 enum l2_packet_filter_type type) 481 { 482 const struct sock_fprog *sock_filter; 483 484 if (TEST_FAIL()) 485 return -1; 486 487 switch (type) { 488 case L2_PACKET_FILTER_DHCP: 489 sock_filter = &dhcp_sock_filter; 490 break; 491 case L2_PACKET_FILTER_NDISC: 492 sock_filter = &ndisc_sock_filter; 493 break; 494 case L2_PACKET_FILTER_PKTTYPE: 495 sock_filter = &pkt_type_sock_filter; 496 break; 497 default: 498 return -1; 499 } 500 501 if (setsockopt(l2->fd, SOL_SOCKET, SO_ATTACH_FILTER, 502 sock_filter, sizeof(struct sock_fprog))) { 503 wpa_printf(MSG_ERROR, 504 "l2_packet_linux: setsockopt(SO_ATTACH_FILTER) failed: %s", 505 strerror(errno)); 506 return -1; 507 } 508 509 return 0; 510 } 511