1 /* SPDX-License-Identifier: BSD-2-Clause */
2 /*
3 * dhcpcd - DHCP client daemon
4 * Copyright (c) 2006-2021 Roy Marples <roy@marples.name>
5 * All rights reserved
6
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #define UUID_LEN 36
30 #define DUID_TIME_EPOCH 946684800
31
32 #include <sys/param.h>
33 #include <sys/socket.h>
34 #include <sys/types.h>
35 #ifdef BSD
36 # include <sys/sysctl.h>
37 #endif
38
39 #include <arpa/inet.h>
40
41 #include <net/if.h>
42 #include <net/if_arp.h>
43
44 #include <errno.h>
45 #include <stdint.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <time.h>
50 #include <unistd.h>
51
52 #include "common.h"
53 #include "dhcpcd.h"
54 #include "duid.h"
55 #include "logerr.h"
56
57 static size_t
duid_machineuuid(char * uuid,size_t uuid_len)58 duid_machineuuid(char *uuid, size_t uuid_len)
59 {
60 int r;
61 size_t len = uuid_len;
62
63 #if defined(HW_UUID) /* OpenBSD */
64 int mib[] = { CTL_HW, HW_UUID };
65
66 r = sysctl(mib, sizeof(mib)/sizeof(mib[0]), uuid, &len, NULL, 0);
67 #elif defined(KERN_HOSTUUID) /* FreeBSD */
68 int mib[] = { CTL_KERN, KERN_HOSTUUID };
69
70 r = sysctl(mib, sizeof(mib)/sizeof(mib[0]), uuid, &len, NULL, 0);
71 #elif defined(__NetBSD__)
72 r = sysctlbyname("machdep.dmi.system-uuid", uuid, &len, NULL, 0);
73 #elif defined(__linux__)
74 FILE *fp;
75
76 fp = fopen("/sys/class/dmi/id/product_uuid", "r");
77 if (fp == NULL)
78 return 0;
79 if (fgets(uuid, (int)uuid_len, fp) == NULL) {
80 fclose(fp);
81 return 0;
82 }
83 len = strlen(uuid) + 1;
84 fclose(fp);
85 r = len == 1 ? -1 : 0;
86 #else
87 UNUSED(uuid);
88 r = -1;
89 errno = ENOSYS;
90 #endif
91
92 if (r == -1)
93 return 0;
94 return len;
95 }
96
97 static size_t
duid_make_uuid(uint8_t * d)98 duid_make_uuid(uint8_t *d)
99 {
100 uint16_t type = htons(DUID_UUID);
101 char uuid[UUID_LEN + 1];
102 size_t l;
103
104 if (duid_machineuuid(uuid, sizeof(uuid)) != sizeof(uuid))
105 return 0;
106
107 /* All zeros UUID is not valid */
108 if (strcmp("00000000-0000-0000-0000-000000000000", uuid) == 0)
109 return 0;
110
111 memcpy(d, &type, sizeof(type));
112 l = sizeof(type);
113 d += sizeof(type);
114 l += hwaddr_aton(d, uuid);
115 return l;
116 }
117
118 size_t
duid_make(void * d,const struct interface * ifp,uint16_t type)119 duid_make(void *d, const struct interface *ifp, uint16_t type)
120 {
121 uint8_t *p;
122 uint16_t u16;
123 time_t t;
124 uint32_t u32;
125
126 if (ifp->hwlen == 0)
127 return 0;
128
129 p = d;
130 u16 = htons(type);
131 memcpy(p, &u16, sizeof(u16));
132 p += sizeof(u16);
133 u16 = htons(ifp->hwtype);
134 memcpy(p, &u16, sizeof(u16));
135 p += sizeof(u16);
136 if (type == DUID_LLT) {
137 /* time returns seconds from jan 1 1970, but DUID-LLT is
138 * seconds from jan 1 2000 modulo 2^32 */
139 t = time(NULL) - DUID_TIME_EPOCH;
140 u32 = htonl((uint32_t)t & 0xffffffff);
141 memcpy(p, &u32, sizeof(u32));
142 p += sizeof(u32);
143 }
144 /* Finally, add the MAC address of the interface */
145 memcpy(p, ifp->hwaddr, ifp->hwlen);
146 p += ifp->hwlen;
147 return (size_t)(p - (uint8_t *)d);
148 }
149
150 #define DUID_STRLEN DUID_LEN * 3
151 static size_t
duid_get(struct dhcpcd_ctx * ctx,const struct interface * ifp)152 duid_get(struct dhcpcd_ctx *ctx, const struct interface *ifp)
153 {
154 uint8_t *data;
155 size_t len, slen;
156 char line[DUID_STRLEN];
157 const struct interface *ifp2;
158
159 /* If we already have a DUID then use it as it's never supposed
160 * to change once we have one even if the interfaces do */
161 if ((len = dhcp_read_hwaddr_aton(ctx, &data, DUID)) != 0) {
162 if (len <= DUID_LEN) {
163 ctx->duid = data;
164 return len;
165 }
166 logerrx("DUID too big (max %u): %s", DUID_LEN, DUID);
167 /* Keep the buffer, will assign below. */
168 } else {
169 if (errno != ENOENT)
170 logerr("%s", DUID);
171 if ((data = malloc(DUID_LEN)) == NULL) {
172 logerr(__func__);
173 return 0;
174 }
175 }
176
177 /* No file? OK, lets make one based the machines UUID */
178 if (ifp == NULL) {
179 if (ctx->duid_type != DUID_DEFAULT &&
180 ctx->duid_type != DUID_UUID)
181 len = 0;
182 else
183 len = duid_make_uuid(data);
184 if (len == 0)
185 free(data);
186 else
187 ctx->duid = data;
188 return len;
189 }
190
191 /* Regardless of what happens we will create a DUID to use. */
192 ctx->duid = data;
193
194 /* No UUID? OK, lets make one based on our interface */
195 if (ifp->hwlen == 0) {
196 logwarnx("%s: does not have hardware address", ifp->name);
197 TAILQ_FOREACH(ifp2, ifp->ctx->ifaces, next) {
198 if (ifp2->hwlen != 0)
199 break;
200 }
201 if (ifp2) {
202 ifp = ifp2;
203 logwarnx("picked interface %s to generate a DUID",
204 ifp->name);
205 } else {
206 if (ctx->duid_type != DUID_LL)
207 logwarnx("no interfaces have a fixed hardware "
208 "address");
209 return duid_make(data, ifp, DUID_LL);
210 }
211 }
212
213 len = duid_make(data, ifp,
214 ctx->duid_type == DUID_LL ? DUID_LL : DUID_LLT);
215 hwaddr_ntoa(data, len, line, sizeof(line));
216 slen = strlen(line);
217 if (slen < sizeof(line) - 2) {
218 line[slen++] = '\n';
219 line[slen] = '\0';
220 }
221 if (dhcp_writefile(ctx, DUID, 0640, line, slen) == -1) {
222 logerr("%s: cannot write duid", __func__);
223 if (ctx->duid_type != DUID_LL)
224 return duid_make(data, ifp, DUID_LL);
225 }
226 return len;
227 }
228
229 size_t
duid_init(struct dhcpcd_ctx * ctx,const struct interface * ifp)230 duid_init(struct dhcpcd_ctx *ctx, const struct interface *ifp)
231 {
232
233 if (ctx->duid == NULL)
234 ctx->duid_len = duid_get(ctx, ifp);
235 return ctx->duid_len;
236 }
237