src/l2_packet/l2_packet_privsep.c

   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 }