xref: /openbmc/u-boot/env/common.c (revision bcdfb8d5) 
1 /*
2  * (C) Copyright 2000-2010
3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4  *
5  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
6  * Andreas Heppel <aheppel@sysgo.de>
7  *
8  * SPDX-License-Identifier:	GPL-2.0+
9  */
10 
11 #include <common.h>
12 #include <command.h>
13 #include <environment.h>
14 #include <linux/stddef.h>
15 #include <search.h>
16 #include <errno.h>
17 #include <malloc.h>
18 
19 DECLARE_GLOBAL_DATA_PTR;
20 
21 /************************************************************************
22  * Default settings to be used when no valid environment is found
23  */
24 #include <env_default.h>
25 
26 struct hsearch_data env_htab = {
27 	.change_ok = env_flags_validate,
28 };
29 
30 __weak uchar env_get_char_spec(int index)
31 {
32 	return *((uchar *)(gd->env_addr + index));
33 }
34 
35 static uchar env_get_char_init(int index)
36 {
37 	/* if crc was bad, use the default environment */
38 	if (gd->env_valid)
39 		return env_get_char_spec(index);
40 	else
41 		return default_environment[index];
42 }
43 
44 static const uchar *env_get_addr(int index)
45 {
46 	if (gd->env_valid)
47 		return (uchar *)(gd->env_addr + index);
48 	else
49 		return &default_environment[index];
50 }
51 
52 static uchar env_get_char_memory(int index)
53 {
54 	return *env_get_addr(index);
55 }
56 
57 uchar env_get_char(int index)
58 {
59 	/* if relocated to RAM */
60 	if (gd->flags & GD_FLG_RELOC)
61 		return env_get_char_memory(index);
62 	else
63 		return env_get_char_init(index);
64 }
65 
66 /*
67  * Read an environment variable as a boolean
68  * Return -1 if variable does not exist (default to true)
69  */
70 int getenv_yesno(const char *var)
71 {
72 	char *s = getenv(var);
73 
74 	if (s == NULL)
75 		return -1;
76 	return (*s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T') ?
77 		1 : 0;
78 }
79 
80 /*
81  * Look up the variable from the default environment
82  */
83 char *getenv_default(const char *name)
84 {
85 	char *ret_val;
86 	unsigned long really_valid = gd->env_valid;
87 	unsigned long real_gd_flags = gd->flags;
88 
89 	/* Pretend that the image is bad. */
90 	gd->flags &= ~GD_FLG_ENV_READY;
91 	gd->env_valid = 0;
92 	ret_val = getenv(name);
93 	gd->env_valid = really_valid;
94 	gd->flags = real_gd_flags;
95 	return ret_val;
96 }
97 
98 void set_default_env(const char *s)
99 {
100 	int flags = 0;
101 
102 	if (sizeof(default_environment) > ENV_SIZE) {
103 		puts("*** Error - default environment is too large\n\n");
104 		return;
105 	}
106 
107 	if (s) {
108 		if (*s == '!') {
109 			printf("*** Warning - %s, "
110 				"using default environment\n\n",
111 				s + 1);
112 		} else {
113 			flags = H_INTERACTIVE;
114 			puts(s);
115 		}
116 	} else {
117 		puts("Using default environment\n\n");
118 	}
119 
120 	if (himport_r(&env_htab, (char *)default_environment,
121 			sizeof(default_environment), '\0', flags, 0,
122 			0, NULL) == 0)
123 		error("Environment import failed: errno = %d\n", errno);
124 
125 	gd->flags |= GD_FLG_ENV_READY;
126 	gd->flags |= GD_FLG_ENV_DEFAULT;
127 }
128 
129 
130 /* [re]set individual variables to their value in the default environment */
131 int set_default_vars(int nvars, char * const vars[])
132 {
133 	/*
134 	 * Special use-case: import from default environment
135 	 * (and use \0 as a separator)
136 	 */
137 	return himport_r(&env_htab, (const char *)default_environment,
138 				sizeof(default_environment), '\0',
139 				H_NOCLEAR | H_INTERACTIVE, 0, nvars, vars);
140 }
141 
142 #ifdef CONFIG_ENV_AES
143 #include <uboot_aes.h>
144 /**
145  * env_aes_cbc_get_key() - Get AES-128-CBC key for the environment
146  *
147  * This function shall return 16-byte array containing AES-128 key used
148  * to encrypt and decrypt the environment. This function must be overridden
149  * by the implementer as otherwise the environment encryption will not
150  * work.
151  */
152 __weak uint8_t *env_aes_cbc_get_key(void)
153 {
154 	return NULL;
155 }
156 
157 static int env_aes_cbc_crypt(env_t *env, const int enc)
158 {
159 	unsigned char *data = env->data;
160 	uint8_t *key;
161 	uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
162 	uint32_t aes_blocks;
163 
164 	key = env_aes_cbc_get_key();
165 	if (!key)
166 		return -EINVAL;
167 
168 	/* First we expand the key. */
169 	aes_expand_key(key, key_exp);
170 
171 	/* Calculate the number of AES blocks to encrypt. */
172 	aes_blocks = ENV_SIZE / AES_KEY_LENGTH;
173 
174 	if (enc)
175 		aes_cbc_encrypt_blocks(key_exp, data, data, aes_blocks);
176 	else
177 		aes_cbc_decrypt_blocks(key_exp, data, data, aes_blocks);
178 
179 	return 0;
180 }
181 #else
182 static inline int env_aes_cbc_crypt(env_t *env, const int enc)
183 {
184 	return 0;
185 }
186 #endif
187 
188 /*
189  * Check if CRC is valid and (if yes) import the environment.
190  * Note that "buf" may or may not be aligned.
191  */
192 int env_import(const char *buf, int check)
193 {
194 	env_t *ep = (env_t *)buf;
195 	int ret;
196 
197 	if (check) {
198 		uint32_t crc;
199 
200 		memcpy(&crc, &ep->crc, sizeof(crc));
201 
202 		if (crc32(0, ep->data, ENV_SIZE) != crc) {
203 			set_default_env("!bad CRC");
204 			return 0;
205 		}
206 	}
207 
208 	/* Decrypt the env if desired. */
209 	ret = env_aes_cbc_crypt(ep, 0);
210 	if (ret) {
211 		error("Failed to decrypt env!\n");
212 		set_default_env("!import failed");
213 		return ret;
214 	}
215 
216 	if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
217 			0, NULL)) {
218 		gd->flags |= GD_FLG_ENV_READY;
219 		return 1;
220 	}
221 
222 	error("Cannot import environment: errno = %d\n", errno);
223 
224 	set_default_env("!import failed");
225 
226 	return 0;
227 }
228 
229 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
230 static unsigned char env_flags;
231 
232 int env_import_redund(const char *buf1, const char *buf2)
233 {
234 	int crc1_ok, crc2_ok;
235 	env_t *ep, *tmp_env1, *tmp_env2;
236 
237 	tmp_env1 = (env_t *)buf1;
238 	tmp_env2 = (env_t *)buf2;
239 
240 	crc1_ok = crc32(0, tmp_env1->data, ENV_SIZE) ==
241 			tmp_env1->crc;
242 	crc2_ok = crc32(0, tmp_env2->data, ENV_SIZE) ==
243 			tmp_env2->crc;
244 
245 	if (!crc1_ok && !crc2_ok) {
246 		set_default_env("!bad CRC");
247 		return 0;
248 	} else if (crc1_ok && !crc2_ok) {
249 		gd->env_valid = 1;
250 	} else if (!crc1_ok && crc2_ok) {
251 		gd->env_valid = 2;
252 	} else {
253 		/* both ok - check serial */
254 		if (tmp_env1->flags == 255 && tmp_env2->flags == 0)
255 			gd->env_valid = 2;
256 		else if (tmp_env2->flags == 255 && tmp_env1->flags == 0)
257 			gd->env_valid = 1;
258 		else if (tmp_env1->flags > tmp_env2->flags)
259 			gd->env_valid = 1;
260 		else if (tmp_env2->flags > tmp_env1->flags)
261 			gd->env_valid = 2;
262 		else /* flags are equal - almost impossible */
263 			gd->env_valid = 1;
264 	}
265 
266 	if (gd->env_valid == 1)
267 		ep = tmp_env1;
268 	else
269 		ep = tmp_env2;
270 
271 	env_flags = ep->flags;
272 	return env_import((char *)ep, 0);
273 }
274 #endif /* CONFIG_SYS_REDUNDAND_ENVIRONMENT */
275 
276 /* Export the environment and generate CRC for it. */
277 int env_export(env_t *env_out)
278 {
279 	char *res;
280 	ssize_t	len;
281 	int ret;
282 
283 	res = (char *)env_out->data;
284 	len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
285 	if (len < 0) {
286 		error("Cannot export environment: errno = %d\n", errno);
287 		return 1;
288 	}
289 
290 	/* Encrypt the env if desired. */
291 	ret = env_aes_cbc_crypt(env_out, 1);
292 	if (ret)
293 		return ret;
294 
295 	env_out->crc = crc32(0, env_out->data, ENV_SIZE);
296 
297 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
298 	env_out->flags = ++env_flags; /* increase the serial */
299 #endif
300 
301 	return 0;
302 }
303 
304 void env_relocate(void)
305 {
306 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
307 	env_reloc();
308 	env_htab.change_ok += gd->reloc_off;
309 #endif
310 	if (gd->env_valid == 0) {
311 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
312 		/* Environment not changable */
313 		set_default_env(NULL);
314 #else
315 		bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
316 		set_default_env("!bad CRC");
317 #endif
318 	} else {
319 		env_relocate_spec();
320 	}
321 }
322 
323 #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
324 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
325 {
326 	ENTRY *match;
327 	int found, idx;
328 
329 	idx = 0;
330 	found = 0;
331 	cmdv[0] = NULL;
332 
333 	while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
334 		int vallen = strlen(match->key) + 1;
335 
336 		if (found >= maxv - 2 || bufsz < vallen)
337 			break;
338 
339 		cmdv[found++] = buf;
340 		memcpy(buf, match->key, vallen);
341 		buf += vallen;
342 		bufsz -= vallen;
343 	}
344 
345 	qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
346 
347 	if (idx)
348 		cmdv[found++] = "...";
349 
350 	cmdv[found] = NULL;
351 	return found;
352 }
353 #endif
354