| 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 | perror("L2: sendmsg(cmd)"); |
| 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 | perror("L2: sendmsg(packet_send)"); |
| 86 | return -1; |
| 87 | } |
| 88 | |
| 89 | return 0; |
| 90 | } |
| 91 | |
| 92 | |
| 93 | static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx) |
| 94 | { |
| 95 | struct l2_packet_data *l2 = eloop_ctx; |
| 96 | u8 buf[2300]; |
| 97 | int res; |
| 98 | struct sockaddr_un from; |
| 99 | socklen_t fromlen = sizeof(from); |
| 100 | |
| 101 | os_memset(&from, 0, sizeof(from)); |
| 102 | res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &from, |
| 103 | &fromlen); |
| 104 | if (res < 0) { |
| 105 | perror("l2_packet_receive - recvfrom"); |
| 106 | return; |
| 107 | } |
| 108 | if (res < ETH_ALEN) { |
| 109 | wpa_printf(MSG_DEBUG, "L2: Too show packet received"); |
| 110 | return; |
| 111 | } |
| 112 | |
| 113 | if (from.sun_family != AF_UNIX || |
| 114 | os_strncmp(from.sun_path, l2->priv_addr.sun_path, |
| 115 | sizeof(from.sun_path)) != 0) { |
| 116 | wpa_printf(MSG_DEBUG, "L2: Received message from unexpected " |
| 117 | "source"); |
| 118 | return; |
| 119 | } |
| 120 | |
| 121 | l2->rx_callback(l2->rx_callback_ctx, buf, buf + ETH_ALEN, |
| 122 | res - ETH_ALEN); |
| 123 | } |
| 124 | |
| 125 | |
| 126 | struct l2_packet_data * l2_packet_init( |
| 127 | const char *ifname, const u8 *own_addr, unsigned short protocol, |
| 128 | void (*rx_callback)(void *ctx, const u8 *src_addr, |
| 129 | const u8 *buf, size_t len), |
| 130 | void *rx_callback_ctx, int l2_hdr) |
| 131 | { |
| 132 | struct l2_packet_data *l2; |
| 133 | char *own_dir = "/tmp"; |
| 134 | char *priv_dir = "/var/run/wpa_priv"; |
| 135 | size_t len; |
| 136 | static unsigned int counter = 0; |
| 137 | struct sockaddr_un addr; |
| 138 | fd_set rfds; |
| 139 | struct timeval tv; |
| 140 | int res; |
| 141 | u8 reply[ETH_ALEN + 1]; |
| 142 | int reg_cmd[2]; |
| 143 | |
| 144 | l2 = os_zalloc(sizeof(struct l2_packet_data)); |
| 145 | if (l2 == NULL) |
| 146 | return NULL; |
| 147 | l2->rx_callback = rx_callback; |
| 148 | l2->rx_callback_ctx = rx_callback_ctx; |
| 149 | |
| 150 | len = os_strlen(own_dir) + 50; |
| 151 | l2->own_socket_path = os_malloc(len); |
| 152 | if (l2->own_socket_path == NULL) { |
| 153 | os_free(l2); |
| 154 | return NULL; |
| 155 | } |
| 156 | os_snprintf(l2->own_socket_path, len, "%s/wpa_privsep-l2-%d-%d", |
| 157 | own_dir, getpid(), counter++); |
| 158 | |
| 159 | l2->priv_addr.sun_family = AF_UNIX; |
| 160 | os_snprintf(l2->priv_addr.sun_path, sizeof(l2->priv_addr.sun_path), |
| 161 | "%s/%s", priv_dir, ifname); |
| 162 | |
| 163 | l2->fd = socket(PF_UNIX, SOCK_DGRAM, 0); |
| 164 | if (l2->fd < 0) { |
| 165 | perror("socket(PF_UNIX)"); |
| 166 | os_free(l2->own_socket_path); |
| 167 | l2->own_socket_path = NULL; |
| 168 | os_free(l2); |
| 169 | return NULL; |
| 170 | } |
| 171 | |
| 172 | os_memset(&addr, 0, sizeof(addr)); |
| 173 | addr.sun_family = AF_UNIX; |
| 174 | os_strlcpy(addr.sun_path, l2->own_socket_path, sizeof(addr.sun_path)); |
| 175 | if (bind(l2->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { |
| 176 | perror("l2-pkt-privsep: bind(PF_UNIX)"); |
| 177 | goto fail; |
| 178 | } |
| 179 | |
| 180 | reg_cmd[0] = protocol; |
| 181 | reg_cmd[1] = l2_hdr; |
| 182 | if (wpa_priv_cmd(l2, PRIVSEP_CMD_L2_REGISTER, reg_cmd, sizeof(reg_cmd)) |
| 183 | < 0) { |
| 184 | wpa_printf(MSG_ERROR, "L2: Failed to register with wpa_priv"); |
| 185 | goto fail; |
| 186 | } |
| 187 | |
| 188 | FD_ZERO(&rfds); |
| 189 | FD_SET(l2->fd, &rfds); |
| 190 | tv.tv_sec = 5; |
| 191 | tv.tv_usec = 0; |
| 192 | res = select(l2->fd + 1, &rfds, NULL, NULL, &tv); |
| 193 | if (res < 0 && errno != EINTR) { |
| 194 | perror("select"); |
| 195 | goto fail; |
| 196 | } |
| 197 | |
| 198 | if (FD_ISSET(l2->fd, &rfds)) { |
| 199 | res = recv(l2->fd, reply, sizeof(reply), 0); |
| 200 | if (res < 0) { |
| 201 | perror("recv"); |
| 202 | goto fail; |
| 203 | } |
| 204 | } else { |
| 205 | wpa_printf(MSG_DEBUG, "L2: Timeout while waiting for " |
| 206 | "registration reply"); |
| 207 | goto fail; |
| 208 | } |
| 209 | |
| 210 | if (res != ETH_ALEN) { |
| 211 | wpa_printf(MSG_DEBUG, "L2: Unexpected registration reply " |
| 212 | "(len=%d)", res); |
| 213 | } |
| 214 | os_memcpy(l2->own_addr, reply, ETH_ALEN); |
| 215 | |
| 216 | eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL); |
| 217 | |
| 218 | return l2; |
| 219 | |
| 220 | fail: |
| 221 | close(l2->fd); |
| 222 | l2->fd = -1; |
| 223 | unlink(l2->own_socket_path); |
| 224 | os_free(l2->own_socket_path); |
| 225 | l2->own_socket_path = NULL; |
| 226 | os_free(l2); |
| 227 | return NULL; |
| 228 | } |
| 229 | |
| 230 | |
| 231 | void l2_packet_deinit(struct l2_packet_data *l2) |
| 232 | { |
| 233 | if (l2 == NULL) |
| 234 | return; |
| 235 | |
| 236 | if (l2->fd >= 0) { |
| 237 | wpa_priv_cmd(l2, PRIVSEP_CMD_L2_UNREGISTER, NULL, 0); |
| 238 | eloop_unregister_read_sock(l2->fd); |
| 239 | close(l2->fd); |
| 240 | } |
| 241 | |
| 242 | if (l2->own_socket_path) { |
| 243 | unlink(l2->own_socket_path); |
| 244 | os_free(l2->own_socket_path); |
| 245 | } |
| 246 | |
| 247 | os_free(l2); |
| 248 | } |
| 249 | |
| 250 | |
| 251 | int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len) |
| 252 | { |
| 253 | /* TODO */ |
| 254 | return -1; |
| 255 | } |
| 256 | |
| 257 | |
| 258 | void l2_packet_notify_auth_start(struct l2_packet_data *l2) |
| 259 | { |
| 260 | wpa_priv_cmd(l2, PRIVSEP_CMD_L2_NOTIFY_AUTH_START, NULL, 0); |
| 261 | } |