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
wpa_priv_cmd(struct l2_packet_data * l2,int cmd,const void * data,size_t data_len)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
l2_packet_get_own_addr(struct l2_packet_data * l2,u8 * addr)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
l2_packet_send(struct l2_packet_data * l2,const u8 * dst_addr,u16 proto,const u8 * buf,size_t len)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
l2_packet_receive(int sock,void * eloop_ctx,void * sock_ctx)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
l2_packet_init(const char * ifname,const u8 * own_addr,unsigned short protocol,void (* rx_callback)(void * ctx,const u8 * src_addr,const u8 * buf,size_t len),void * rx_callback_ctx,int l2_hdr)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
l2_packet_init_bridge(const char * br_ifname,const char * ifname,const u8 * own_addr,unsigned short protocol,void (* rx_callback)(void * ctx,const u8 * src_addr,const u8 * buf,size_t len),void * rx_callback_ctx,int l2_hdr)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
l2_packet_deinit(struct l2_packet_data * l2)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
l2_packet_get_ip_addr(struct l2_packet_data * l2,char * buf,size_t len)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
l2_packet_notify_auth_start(struct l2_packet_data * l2)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
l2_packet_set_packet_filter(struct l2_packet_data * l2,enum l2_packet_filter_type type)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