env/common.c

   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 /*
  31  * Read an environment variable as a boolean
  32  * Return -1 if variable does not exist (default to true)
  33  */
  34 int env_get_yesno(const char *var)
  35 {
  36         char *s = env_get(var);
  37
  38         if (s == NULL)
  39                 return -1;
  40         return (*s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T') ?
  41                 1 : 0;
  42 }
  43
  44 /*
  45  * Look up the variable from the default environment
  46  */
  47 char *getenv_default(const char *name)
  48 {
  49         char *ret_val;
  50         unsigned long really_valid = gd->env_valid;
  51         unsigned long real_gd_flags = gd->flags;
  52
  53         /* Pretend that the image is bad. */
  54         gd->flags &= ~GD_FLG_ENV_READY;
  55         gd->env_valid = 0;
  56         ret_val = env_get(name);
  57         gd->env_valid = really_valid;
  58         gd->flags = real_gd_flags;
  59         return ret_val;
  60 }
  61
  62 void set_default_env(const char *s)
  63 {
  64         int flags = 0;
  65
  66         if (sizeof(default_environment) > ENV_SIZE) {
  67                 puts("*** Error - default environment is too large\n\n");
  68                 return;
  69         }
  70
  71         if (s) {
  72                 if (*s == '!') {
  73                         printf("*** Warning - %s, "
  74                                 "using default environment\n\n",
  75                                 s + 1);
  76                 } else {
  77                         flags = H_INTERACTIVE;
  78                         puts(s);
  79                 }
  80         } else {
  81                 puts("Using default environment\n\n");
  82         }
  83
  84         if (himport_r(&env_htab, (char *)default_environment,
  85                         sizeof(default_environment), '\0', flags, 0,
  86                         0, NULL) == 0)
  87                 error("Environment import failed: errno = %d\n", errno);
  88
  89         gd->flags |= GD_FLG_ENV_READY;
  90         gd->flags |= GD_FLG_ENV_DEFAULT;
  91 }
  92
  93
  94 /* [re]set individual variables to their value in the default environment */
  95 int set_default_vars(int nvars, char * const vars[])
  96 {
  97         /*
  98          * Special use-case: import from default environment
  99          * (and use \0 as a separator)
 100          */
 101         return himport_r(&env_htab, (const char *)default_environment,
 102                                 sizeof(default_environment), '\0',
 103                                 H_NOCLEAR | H_INTERACTIVE, 0, nvars, vars);
 104 }
 105
 106 #ifdef CONFIG_ENV_AES
 107 #include <uboot_aes.h>
 108 /**
 109  * env_aes_cbc_get_key() - Get AES-128-CBC key for the environment
 110  *
 111  * This function shall return 16-byte array containing AES-128 key used
 112  * to encrypt and decrypt the environment. This function must be overridden
 113  * by the implementer as otherwise the environment encryption will not
 114  * work.
 115  */
 116 __weak uint8_t *env_aes_cbc_get_key(void)
 117 {
 118         return NULL;
 119 }
 120
 121 static int env_aes_cbc_crypt(env_t *env, const int enc)
 122 {
 123         unsigned char *data = env->data;
 124         uint8_t *key;
 125         uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
 126         uint32_t aes_blocks;
 127
 128         key = env_aes_cbc_get_key();
 129         if (!key)
 130                 return -EINVAL;
 131
 132         /* First we expand the key. */
 133         aes_expand_key(key, key_exp);
 134
 135         /* Calculate the number of AES blocks to encrypt. */
 136         aes_blocks = ENV_SIZE / AES_KEY_LENGTH;
 137
 138         if (enc)
 139                 aes_cbc_encrypt_blocks(key_exp, data, data, aes_blocks);
 140         else
 141                 aes_cbc_decrypt_blocks(key_exp, data, data, aes_blocks);
 142
 143         return 0;
 144 }
 145 #else
 146 static inline int env_aes_cbc_crypt(env_t *env, const int enc)
 147 {
 148         return 0;
 149 }
 150 #endif
 151
 152 /*
 153  * Check if CRC is valid and (if yes) import the environment.
 154  * Note that "buf" may or may not be aligned.
 155  */
 156 int env_import(const char *buf, int check)
 157 {
 158         env_t *ep = (env_t *)buf;
 159         int ret;
 160
 161         if (check) {
 162                 uint32_t crc;
 163
 164                 memcpy(&crc, &ep->crc, sizeof(crc));
 165
 166                 if (crc32(0, ep->data, ENV_SIZE) != crc) {
 167                         set_default_env("!bad CRC");
 168                         return 0;
 169                 }
 170         }
 171
 172         /* Decrypt the env if desired. */
 173         ret = env_aes_cbc_crypt(ep, 0);
 174         if (ret) {
 175                 error("Failed to decrypt env!\n");
 176                 set_default_env("!import failed");
 177                 return ret;
 178         }
 179
 180         if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
 181                         0, NULL)) {
 182                 gd->flags |= GD_FLG_ENV_READY;
 183                 return 1;
 184         }
 185
 186         error("Cannot import environment: errno = %d\n", errno);
 187
 188         set_default_env("!import failed");
 189
 190         return 0;
 191 }
 192
 193 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 194 static unsigned char env_flags;
 195
 196 int env_import_redund(const char *buf1, const char *buf2)
 197 {
 198         int crc1_ok, crc2_ok;
 199         env_t *ep, *tmp_env1, *tmp_env2;
 200
 201         tmp_env1 = (env_t *)buf1;
 202         tmp_env2 = (env_t *)buf2;
 203
 204         crc1_ok = crc32(0, tmp_env1->data, ENV_SIZE) ==
 205                         tmp_env1->crc;
 206         crc2_ok = crc32(0, tmp_env2->data, ENV_SIZE) ==
 207                         tmp_env2->crc;
 208
 209         if (!crc1_ok && !crc2_ok) {
 210                 set_default_env("!bad CRC");
 211                 return 0;
 212         } else if (crc1_ok && !crc2_ok) {
 213                 gd->env_valid = 1;
 214         } else if (!crc1_ok && crc2_ok) {
 215                 gd->env_valid = 2;
 216         } else {
 217                 /* both ok - check serial */
 218                 if (tmp_env1->flags == 255 && tmp_env2->flags == 0)
 219                         gd->env_valid = 2;
 220                 else if (tmp_env2->flags == 255 && tmp_env1->flags == 0)
 221                         gd->env_valid = 1;
 222                 else if (tmp_env1->flags > tmp_env2->flags)
 223                         gd->env_valid = 1;
 224                 else if (tmp_env2->flags > tmp_env1->flags)
 225                         gd->env_valid = 2;
 226                 else /* flags are equal - almost impossible */
 227                         gd->env_valid = 1;
 228         }
 229
 230         if (gd->env_valid == 1)
 231                 ep = tmp_env1;
 232         else
 233                 ep = tmp_env2;
 234
 235         env_flags = ep->flags;
 236         return env_import((char *)ep, 0);
 237 }
 238 #endif /* CONFIG_SYS_REDUNDAND_ENVIRONMENT */
 239
 240 /* Export the environment and generate CRC for it. */
 241 int env_export(env_t *env_out)
 242 {
 243         char *res;
 244         ssize_t len;
 245         int ret;
 246
 247         res = (char *)env_out->data;
 248         len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
 249         if (len < 0) {
 250                 error("Cannot export environment: errno = %d\n", errno);
 251                 return 1;
 252         }
 253
 254         /* Encrypt the env if desired. */
 255         ret = env_aes_cbc_crypt(env_out, 1);
 256         if (ret)
 257                 return ret;
 258
 259         env_out->crc = crc32(0, env_out->data, ENV_SIZE);
 260
 261 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 262         env_out->flags = ++env_flags; /* increase the serial */
 263 #endif
 264
 265         return 0;
 266 }
 267
 268 void env_relocate(void)
 269 {
 270 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 271         env_reloc();
 272         env_htab.change_ok += gd->reloc_off;
 273 #endif
 274         if (gd->env_valid == 0) {
 275 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
 276                 /* Environment not changable */
 277                 set_default_env(NULL);
 278 #else
 279                 bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
 280                 set_default_env("!bad CRC");
 281 #endif
 282         } else {
 283                 env_load();
 284         }
 285 }
 286
 287 #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
 288 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
 289 {
 290         ENTRY *match;
 291         int found, idx;
 292
 293         idx = 0;
 294         found = 0;
 295         cmdv[0] = NULL;
 296
 297         while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
 298                 int vallen = strlen(match->key) + 1;
 299
 300                 if (found >= maxv - 2 || bufsz < vallen)
 301                         break;
 302
 303                 cmdv[found++] = buf;
 304                 memcpy(buf, match->key, vallen);
 305                 buf += vallen;
 306                 bufsz -= vallen;
 307         }
 308
 309         qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
 310
 311         if (idx)
 312                 cmdv[found++] = "...";
 313
 314         cmdv[found] = NULL;
 315         return found;
 316 }
 317 #endif