xref: /freebsd/lib/libefivar/efivar.c (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
1 /*-
2  * Copyright (c) 2016 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 #include <efivar.h>
28 #include <sys/efiio.h>
29 #include <sys/param.h>
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 
36 #include "efichar.h"
37 
38 static int efi_fd = -2;
39 
40 #define Z { 0, 0, 0, 0, 0, { 0 } }
41 
42 const efi_guid_t efi_guid_empty = Z;
43 
44 static struct uuid_table guid_tbl [] =
45 {
46 	{ "00000000-0000-0000-0000-000000000000", "zero", Z },
47 	{ "093e0fae-a6c4-4f50-9f1b-d41e2b89c19a", "sha512", Z },
48 	{ "0abba7dc-e516-4167-bbf5-4d9d1c739416", "redhat", Z },
49 	{ "0b6e5233-a65c-44c9-9407-d9ab83bfc8bd", "sha224", Z },
50 	{ "126a762d-5758-4fca-8531-201a7f57f850", "lenovo_boot_menu", Z },
51 	{ "3bd2a492-96c0-4079-b420-fcf98ef103ed", "x509_sha256", Z },
52 	{ "3c5766e8-269c-4e34-aa14-ed776e85b3b6", "rsa2048", Z },
53 	{ "3CC24E96-22C7-41D8-8863-8E39DCDCC2CF", "lenovo", Z },
54 	{ "3f7e615b-0d45-4f80-88dc-26b234958560", "lenovo_diag", Z },
55 	{ "446dbf63-2502-4cda-bcfa-2465d2b0fe9d", "x509_sha512", Z },
56 	{ "4aafd29d-68df-49ee-8aa9-347d375665a7", "pkcs7_cert", Z },
57 	{ "605dab50-e046-4300-abb6-3dd810dd8b23", "shim", Z },
58 	{ "665d3f60-ad3e-4cad-8e26-db46eee9f1b5", "lenovo_rescue", Z },
59 	{ "67f8444f-8743-48f1-a328-1eaab8736080", "rsa2048_sha1", Z },
60 	{ "7076876e-80c2-4ee6-aad2-28b349a6865b", "x509_sha384", Z },
61 	{ "721c8b66-426c-4e86-8e99-3457c46ab0b9", "lenovo_setup", Z },
62 	{ "77fa9abd-0359-4d32-bd60-28f4e78f784b", "microsoft", Z },
63 	{ "7FACC7B6-127F-4E9C-9C5D-080F98994345", "lenovo_2", Z },
64 	{ "826ca512-cf10-4ac9-b187-be01496631bd", "sha1", Z },
65 	{ "82988420-7467-4490-9059-feb448dd1963", "lenovo_me_config", Z },
66 	{ "8be4df61-93ca-11d2-aa0d-00e098032b8c", "global", Z },
67 	{ "a5c059a1-94e4-4aa7-87b5-ab155c2bf072", "x509_cert", Z },
68 	{ "a7717414-c616-4977-9420-844712a735bf", "rsa2048_sha256_cert", Z },
69 	{ "a7d8d9a6-6ab0-4aeb-ad9d-163e59a7a380", "lenovo_diag_splash", Z },
70 	{ "ade9e48f-9cb8-98e6-31af-b4e6009e2fe3", "redhat_2", Z },
71 	{ "bc7838d2-0f82-4d60-8316-c068ee79d25b", "lenovo_msg", Z },
72 	{ "c1c41626-504c-4092-aca9-41f936934328", "sha256", Z },
73 	{ "c57ad6b7-0515-40a8-9d21-551652854e37", "shell", Z },
74 	{ "d719b2cb-3d3a-4596-a3bc-dad00e67656f", "security", Z },
75 	{ "e2b36190-879b-4a3d-ad8d-f2e7bba32784", "rsa2048_sha256", Z },
76 	{ "ff3e5307-9fd0-48c9-85f1-8ad56c701e01", "sha384", Z },
77 	{ "f46ee6f4-4785-43a3-923d-7f786c3c8479", "lenovo_startup_interrupt", Z },
78 	{ "ffffffff-ffff-ffff-ffff-ffffffffffff", "zzignore-this-guid", Z },
79 };
80 #undef Z
81 
82 static void
83 efi_guid_tbl_compile(void)
84 {
85 	size_t i;
86 	uint32_t status;
87 	static int done = 0;
88 
89 	if (done)
90 		return;
91 	for (i = 0; i < nitems(guid_tbl); i++) {
92 		uuid_from_string(guid_tbl[i].uuid_str, &guid_tbl[i].guid,
93 		    &status);
94 		/* all f's is a bad version, so ignore that error */
95 		if (status != uuid_s_ok && status != uuid_s_bad_version)
96 			fprintf(stderr, "Can't convert %s to a uuid for %s: %d\n",
97 			    guid_tbl[i].uuid_str, guid_tbl[i].name, (int)status);
98 	}
99 	done = 1;
100 }
101 
102 int
103 efi_known_guid(struct uuid_table **tbl)
104 {
105 
106 	*tbl = guid_tbl;
107 	return (nitems(guid_tbl));
108 }
109 
110 static int
111 efi_open_dev(void)
112 {
113 
114 	if (efi_fd == -2)
115 		efi_fd = open("/dev/efi", O_RDWR);
116 	if (efi_fd < 0)
117 		efi_fd = -1;
118 	else
119 		efi_guid_tbl_compile();
120 	return (efi_fd);
121 }
122 
123 static void
124 efi_var_reset(struct efi_var_ioc *var)
125 {
126 	var->name = NULL;
127 	var->namesize = 0;
128 	memset(&var->vendor, 0, sizeof(var->vendor));
129 	var->attrib = 0;
130 	var->data = NULL;
131 	var->datasize = 0;
132 }
133 
134 static int
135 rv_to_linux_rv(int rv)
136 {
137 	if (rv == 0)
138 		rv = 1;
139 	else
140 		rv = -errno;
141 	return (rv);
142 }
143 
144 int
145 efi_append_variable(efi_guid_t guid, const char *name,
146     uint8_t *data, size_t data_size, uint32_t attributes)
147 {
148 
149 	return efi_set_variable(guid, name, data, data_size,
150 	    attributes | EFI_VARIABLE_APPEND_WRITE);
151 }
152 
153 int
154 efi_del_variable(efi_guid_t guid, const char *name)
155 {
156 
157 	/* data_size of 0 deletes the variable */
158 	return efi_set_variable(guid, name, NULL, 0, 0);
159 }
160 
161 int
162 efi_get_variable(efi_guid_t guid, const char *name,
163     uint8_t **data, size_t *data_size, uint32_t *attributes)
164 {
165 	struct efi_var_ioc var;
166 	int rv;
167 	static uint8_t buf[1024*32];
168 
169 	if (efi_open_dev() == -1)
170 		return -1;
171 
172 	efi_var_reset(&var);
173 	rv = utf8_to_ucs2(name, &var.name, &var.namesize);
174 	if (rv != 0)
175 		goto errout;
176 	var.vendor = guid;
177 	var.data = buf;
178 	var.datasize = sizeof(buf);
179 	rv = ioctl(efi_fd, EFIIOC_VAR_GET, &var);
180 	if (data_size != NULL)
181 		*data_size = var.datasize;
182 	if (data != NULL)
183 		*data = buf;
184 	if (attributes != NULL)
185 		*attributes = var.attrib;
186 errout:
187 	free(var.name);
188 
189 	return rv_to_linux_rv(rv);
190 }
191 
192 int
193 efi_get_variable_attributes(efi_guid_t guid, const char *name,
194     uint32_t *attributes)
195 {
196 	/* Make sure this construct works -- I think it will fail */
197 
198 	return efi_get_variable(guid, name, NULL, NULL, attributes);
199 }
200 
201 int
202 efi_get_variable_size(efi_guid_t guid, const char *name,
203     size_t *size)
204 {
205 
206 	/* XXX check to make sure this matches the linux value */
207 
208 	*size = 0;
209 	return efi_get_variable(guid, name, NULL, size, NULL);
210 }
211 
212 int
213 efi_get_next_variable_name(efi_guid_t **guid, char **name)
214 {
215 	struct efi_var_ioc var;
216 	int rv;
217 	static efi_char *buf;
218 	static size_t buflen = 256 * sizeof(efi_char);
219 	static efi_guid_t retguid;
220 	size_t size;
221 
222 	if (efi_open_dev() == -1)
223 		return -1;
224 
225 	/*
226 	 * Always allocate enough for an extra NUL on the end, but don't tell
227 	 * the IOCTL about it so we can NUL terminate the name before converting
228 	 * it to UTF8.
229 	 */
230 	if (buf == NULL)
231 		buf = malloc(buflen + sizeof(efi_char));
232 
233 again:
234 	efi_var_reset(&var);
235 	var.name = buf;
236 	var.namesize = buflen;
237 	if (*name == NULL) {
238 		*buf = 0;
239 		/* GUID zeroed in var_reset */
240 	} else {
241 		rv = utf8_to_ucs2(*name, &var.name, &size);
242 		if (rv != 0)
243 			goto errout;
244 		var.vendor = **guid;
245 	}
246 	rv = ioctl(efi_fd, EFIIOC_VAR_NEXT, &var);
247 	if (rv == 0 && var.name == NULL) {
248 		/*
249 		 * Variable name not long enough, so allocate more space for the
250 		 * name and try again. As above, mind the NUL we add.
251 		 */
252 		void *new = realloc(buf, var.namesize + sizeof(efi_char));
253 		if (new == NULL) {
254 			rv = -1;
255 			errno = ENOMEM;
256 			goto done;
257 		}
258 		buflen = var.namesize;
259 		buf = new;
260 		goto again;
261 	}
262 
263 	if (rv == 0) {
264 		free(*name);			/* Free last name, to avoid leaking */
265 		*name = NULL;			/* Force ucs2_to_utf8 to malloc new space */
266 		var.name[var.namesize / sizeof(efi_char)] = 0;	/* EFI doesn't NUL terminate */
267 		rv = ucs2_to_utf8(var.name, name);
268 		if (rv != 0)
269 			goto errout;
270 		retguid = var.vendor;
271 		*guid = &retguid;
272 	}
273 errout:
274 
275 	/* XXX The linux interface expects name to be a static buffer -- fix or leak memory? */
276 	/* XXX for the moment, we free just before we'd leak, but still leak last one */
277 done:
278 	if (rv != 0 && errno == ENOENT) {
279 		errno = 0;
280 		free(*name);			/* Free last name, to avoid leaking */
281 		return 0;
282 	}
283 
284 	return (rv_to_linux_rv(rv));
285 }
286 
287 int
288 efi_guid_cmp(const efi_guid_t *guid1, const efi_guid_t *guid2)
289 {
290 	uint32_t status;
291 
292 	return uuid_compare(guid1, guid2, &status);
293 }
294 
295 int
296 efi_guid_is_zero(const efi_guid_t *guid)
297 {
298 	uint32_t status;
299 
300 	return uuid_is_nil(guid, &status);
301 }
302 
303 int
304 efi_guid_to_name(efi_guid_t *guid, char **name)
305 {
306 	size_t i;
307 	uint32_t status;
308 
309 	efi_guid_tbl_compile();
310 	for (i = 0; i < nitems(guid_tbl); i++) {
311 		if (uuid_equal(guid, &guid_tbl[i].guid, &status)) {
312 			*name = strdup(guid_tbl[i].name);
313 			return (0);
314 		}
315 	}
316 	return (efi_guid_to_str(guid, name));
317 }
318 
319 int
320 efi_guid_to_symbol(efi_guid_t *guid __unused, char **symbol __unused)
321 {
322 
323 	/*
324 	 * Unsure what this is used for, efibootmgr doesn't use it.
325 	 * Leave unimplemented for now.
326 	 */
327 	return -1;
328 }
329 
330 int
331 efi_guid_to_str(const efi_guid_t *guid, char **sp)
332 {
333 	uint32_t status;
334 
335 	/* knows efi_guid_t is a typedef of uuid_t */
336 	uuid_to_string(guid, sp, &status);
337 
338 	return (status == uuid_s_ok ? 0 : -1);
339 }
340 
341 int
342 efi_name_to_guid(const char *name, efi_guid_t *guid)
343 {
344 	size_t i;
345 
346 	efi_guid_tbl_compile();
347 	for (i = 0; i < nitems(guid_tbl); i++) {
348 		if (strcmp(name, guid_tbl[i].name) == 0) {
349 			*guid = guid_tbl[i].guid;
350 			return (0);
351 		}
352 	}
353 	return (efi_str_to_guid(name, guid));
354 }
355 
356 int
357 efi_set_variable(efi_guid_t guid, const char *name,
358     uint8_t *data, size_t data_size, uint32_t attributes)
359 {
360 	struct efi_var_ioc var;
361 	int rv;
362 
363 	if (efi_open_dev() == -1)
364 		return -1;
365 
366 	efi_var_reset(&var);
367 	rv = utf8_to_ucs2(name, &var.name, &var.namesize);
368 	if (rv != 0)
369 		goto errout;
370 	var.vendor = guid;
371 	var.data = data;
372 	var.datasize = data_size;
373 	var.attrib = attributes;
374 	rv = ioctl(efi_fd, EFIIOC_VAR_SET, &var);
375 errout:
376 	free(var.name);
377 
378 	return rv;
379 }
380 
381 int
382 efi_str_to_guid(const char *s, efi_guid_t *guid)
383 {
384 	uint32_t status;
385 
386 	/* knows efi_guid_t is a typedef of uuid_t */
387 	uuid_from_string(s, guid, &status);
388 
389 	return (status == uuid_s_ok ? 0 : -1);
390 }
391 
392 int
393 efi_variables_supported(void)
394 {
395 
396 	return efi_open_dev() != -1;
397 }
398