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 } 262