1 /* 2 * WPA Supplicant - Layer2 packet handling with privilege separation 3 * Copyright (c) 2007, 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/un.h> 11 12 #include "common.h" 13 #include "eloop.h" 14 #include "l2_packet.h" 15 #include "common/privsep_commands.h" 16 17 18 struct l2_packet_data { 19 int fd; /* UNIX domain socket for privsep access */ 20 void (*rx_callback)(void *ctx, const u8 *src_addr, 21 const u8 *buf, size_t len); 22 void *rx_callback_ctx; 23 u8 own_addr[ETH_ALEN]; 24 char *own_socket_path; 25 struct sockaddr_un priv_addr; 26 }; 27 28 29 static int wpa_priv_cmd(struct l2_packet_data *l2, int cmd, 30 const void *data, size_t data_len) 31 { 32 struct msghdr msg; 33 struct iovec io[2]; 34 35 io[0].iov_base = &cmd; 36 io[0].iov_len = sizeof(cmd); 37 io[1].iov_base = (u8 *) data; 38 io[1].iov_len = data_len; 39 40 os_memset(&msg, 0, sizeof(msg)); 41 msg.msg_iov = io; 42 msg.msg_iovlen = data ? 2 : 1; 43 msg.msg_name = &l2->priv_addr; 44 msg.msg_namelen = sizeof(l2->priv_addr); 45 46 if (sendmsg(l2->fd, &msg, 0) < 0) { 47 wpa_printf(MSG_ERROR, "L2: sendmsg(cmd): %s", strerror(errno)); 48 return -1; 49 } 50 51 return 0; 52 } 53 54 55 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr) 56 { 57 os_memcpy(addr, l2->own_addr, ETH_ALEN); 58 return 0; 59 } 60 61 62 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto, 63 const u8 *buf, size_t len) 64 { 65 struct msghdr msg; 66 struct iovec io[4]; 67 int cmd = PRIVSEP_CMD_L2_SEND; 68 69 io[0].iov_base = &cmd; 70 io[0].iov_len = sizeof(cmd); 71 io[1].iov_base = &dst_addr; 72 io[1].iov_len = ETH_ALEN; 73 io[2].iov_base = &proto; 74 io[2].iov_len = 2; 75 io[3].iov_base = (u8 *) buf; 76 io[3].iov_len = len; 77 78 os_memset(&msg, 0, sizeof(msg)); 79 msg.msg_iov = io; 80 msg.msg_iovlen = 4; 81 msg.msg_name = &l2->priv_addr; 82 msg.msg_namelen = sizeof(l2->priv_addr); 83 84 if (sendmsg(l2->fd, &msg, 0) < 0) { 85 wpa_printf(MSG_ERROR, "L2: sendmsg(packet_send): %s", 86 strerror(errno)); 87 return -1; 88 } 89 90 return 0; 91 } 92 93 94 static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx) 95 { 96 struct l2_packet_data *l2 = eloop_ctx; 97 u8 buf[2300]; 98 int res; 99 struct sockaddr_un from; 100 socklen_t fromlen = sizeof(from); 101 102 os_memset(&from, 0, sizeof(from)); 103 res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &from, 104 &fromlen); 105 if (res < 0) { 106 wpa_printf(MSG_ERROR, "l2_packet_receive - recvfrom: %s", 107 strerror(errno)); 108 return; 109 } 110 if (res < ETH_ALEN) { 111 wpa_printf(MSG_DEBUG, "L2: Too show packet received"); 112 return; 113 } 114 115 if (from.sun_family != AF_UNIX || 116 os_strncmp(from.sun_path, l2->priv_addr.sun_path, 117 sizeof(from.sun_path)) != 0) { 118 wpa_printf(MSG_DEBUG, "L2: Received message from unexpected " 119 "source"); 120 return; 121 } 122 123 l2->rx_callback(l2->rx_callback_ctx, buf, buf + ETH_ALEN, 124 res - ETH_ALEN); 125 } 126 127 128 struct l2_packet_data * l2_packet_init( 129 const char *ifname, const u8 *own_addr, unsigned short protocol, 130 void (*rx_callback)(void *ctx, const u8 *src_addr, 131 const u8 *buf, size_t len), 132 void *rx_callback_ctx, int l2_hdr) 133 { 134 struct l2_packet_data *l2; 135 char *own_dir = "/tmp"; 136 char *priv_dir = "/var/run/wpa_priv"; 137 size_t len; 138 static unsigned int counter = 0; 139 struct sockaddr_un addr; 140 fd_set rfds; 141 struct timeval tv; 142 int res; 143 u8 reply[ETH_ALEN + 1]; 144 int reg_cmd[2]; 145 146 l2 = os_zalloc(sizeof(struct l2_packet_data)); 147 if (l2 == NULL) 148 return NULL; 149 l2->rx_callback = rx_callback; 150 l2->rx_callback_ctx = rx_callback_ctx; 151 152 len = os_strlen(own_dir) + 50; 153 l2->own_socket_path = os_malloc(len); 154 if (l2->own_socket_path == NULL) { 155 os_free(l2); 156 return NULL; 157 } 158 os_snprintf(l2->own_socket_path, len, "%s/wpa_privsep-l2-%d-%d", 159 own_dir, getpid(), counter++); 160 161 l2->priv_addr.sun_family = AF_UNIX; 162 os_snprintf(l2->priv_addr.sun_path, sizeof(l2->priv_addr.sun_path), 163 "%s/%s", priv_dir, ifname); 164 165 l2->fd = socket(PF_UNIX, SOCK_DGRAM, 0); 166 if (l2->fd < 0) { 167 wpa_printf(MSG_ERROR, "socket(PF_UNIX): %s", strerror(errno)); 168 os_free(l2->own_socket_path); 169 l2->own_socket_path = NULL; 170 os_free(l2); 171 return NULL; 172 } 173 174 os_memset(&addr, 0, sizeof(addr)); 175 addr.sun_family = AF_UNIX; 176 os_strlcpy(addr.sun_path, l2->own_socket_path, sizeof(addr.sun_path)); 177 if (bind(l2->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { 178 wpa_printf(MSG_ERROR, "l2-pkt-privsep: bind(PF_UNIX): %s", 179 strerror(errno)); 180 goto fail; 181 } 182 183 reg_cmd[0] = protocol; 184 reg_cmd[1] = l2_hdr; 185 if (wpa_priv_cmd(l2, PRIVSEP_CMD_L2_REGISTER, reg_cmd, sizeof(reg_cmd)) 186 < 0) { 187 wpa_printf(MSG_ERROR, "L2: Failed to register with wpa_priv"); 188 goto fail; 189 } 190 191 FD_ZERO(&rfds); 192 FD_SET(l2->fd, &rfds); 193 tv.tv_sec = 5; 194 tv.tv_usec = 0; 195 res = select(l2->fd + 1, &rfds, NULL, NULL, &tv); 196 if (res < 0 && errno != EINTR) { 197 wpa_printf(MSG_ERROR, "select: %s", strerror(errno)); 198 goto fail; 199 } 200 201 if (FD_ISSET(l2->fd, &rfds)) { 202 res = recv(l2->fd, reply, sizeof(reply), 0); 203 if (res < 0) { 204 wpa_printf(MSG_ERROR, "recv: %s", strerror(errno)); 205 goto fail; 206 } 207 } else { 208 wpa_printf(MSG_DEBUG, "L2: Timeout while waiting for " 209 "registration reply"); 210 goto fail; 211 } 212 213 if (res != ETH_ALEN) { 214 wpa_printf(MSG_DEBUG, "L2: Unexpected registration reply " 215 "(len=%d)", res); 216 } 217 os_memcpy(l2->own_addr, reply, ETH_ALEN); 218 219 eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL); 220 221 return l2; 222 223 fail: 224 close(l2->fd); 225 l2->fd = -1; 226 unlink(l2->own_socket_path); 227 os_free(l2->own_socket_path); 228 l2->own_socket_path = NULL; 229 os_free(l2); 230 return NULL; 231 } 232 233 234 struct l2_packet_data * l2_packet_init_bridge( 235 const char *br_ifname, const char *ifname, const u8 *own_addr, 236 unsigned short protocol, 237 void (*rx_callback)(void *ctx, const u8 *src_addr, 238 const u8 *buf, size_t len), 239 void *rx_callback_ctx, int l2_hdr) 240 { 241 return l2_packet_init(br_ifname, own_addr, protocol, rx_callback, 242 rx_callback_ctx, l2_hdr); 243 } 244 245 246 void l2_packet_deinit(struct l2_packet_data *l2) 247 { 248 if (l2 == NULL) 249 return; 250 251 if (l2->fd >= 0) { 252 wpa_priv_cmd(l2, PRIVSEP_CMD_L2_UNREGISTER, NULL, 0); 253 eloop_unregister_read_sock(l2->fd); 254 close(l2->fd); 255 } 256 257 if (l2->own_socket_path) { 258 unlink(l2->own_socket_path); 259 os_free(l2->own_socket_path); 260 } 261 262 os_free(l2); 263 } 264 265 266 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len) 267 { 268 /* TODO */ 269 return -1; 270 } 271 272 273 void l2_packet_notify_auth_start(struct l2_packet_data *l2) 274 { 275 wpa_priv_cmd(l2, PRIVSEP_CMD_L2_NOTIFY_AUTH_START, NULL, 0); 276 } 277 278 279 int l2_packet_set_packet_filter(struct l2_packet_data *l2, 280 enum l2_packet_filter_type type) 281 { 282 return -1; 283 } 284