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 __weak uchar env_get_char_spec(int index)
  31 {
  32         return *(uchar *)(gd->env_addr + index);
  33 }
  34
  35 uchar env_get_char(int index)
  36 {
  37         /* if env is not set up, or crc was bad, use the default environment */
  38         if (!gd->env_valid)
  39                 return default_environment[index];
  40         else
  41                 return env_get_char_spec(index);
  42 }
  43
  44 /*
  45  * Read an environment variable as a boolean
  46  * Return -1 if variable does not exist (default to true)
  47  */
  48 int getenv_yesno(const char *var)
  49 {
  50         char *s = getenv(var);
  51
  52         if (s == NULL)
  53                 return -1;
  54         return (*s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T') ?
  55                 1 : 0;
  56 }
  57
  58 /*
  59  * Look up the variable from the default environment
  60  */
  61 char *getenv_default(const char *name)
  62 {
  63         char *ret_val;
  64         unsigned long really_valid = gd->env_valid;
  65         unsigned long real_gd_flags = gd->flags;
  66
  67         /* Pretend that the image is bad. */
  68         gd->flags &= ~GD_FLG_ENV_READY;
  69         gd->env_valid = 0;
  70         ret_val = getenv(name);
  71         gd->env_valid = really_valid;
  72         gd->flags = real_gd_flags;
  73         return ret_val;
  74 }
  75
  76 void set_default_env(const char *s)
  77 {
  78         int flags = 0;
  79
  80         if (sizeof(default_environment) > ENV_SIZE) {
  81                 puts("*** Error - default environment is too large\n\n");
  82                 return;
  83         }
  84
  85         if (s) {
  86                 if (*s == '!') {
  87                         printf("*** Warning - %s, "
  88                                 "using default environment\n\n",
  89                                 s + 1);
  90                 } else {
  91                         flags = H_INTERACTIVE;
  92                         puts(s);
  93                 }
  94         } else {
  95                 puts("Using default environment\n\n");
  96         }
  97
  98         if (himport_r(&env_htab, (char *)default_environment,
  99                         sizeof(default_environment), '\0', flags, 0,
 100                         0, NULL) == 0)
 101                 error("Environment import failed: errno = %d\n", errno);
 102
 103         gd->flags |= GD_FLG_ENV_READY;
 104         gd->flags |= GD_FLG_ENV_DEFAULT;
 105 }
 106
 107
 108 /* [re]set individual variables to their value in the default environment */
 109 int set_default_vars(int nvars, char * const vars[])
 110 {
 111         /*
 112          * Special use-case: import from default environment
 113          * (and use \0 as a separator)
 114          */
 115         return himport_r(&env_htab, (const char *)default_environment,
 116                                 sizeof(default_environment), '\0',
 117                                 H_NOCLEAR | H_INTERACTIVE, 0, nvars, vars);
 118 }
 119
 120 #ifdef CONFIG_ENV_AES
 121 #include <uboot_aes.h>
 122 /**
 123  * env_aes_cbc_get_key() - Get AES-128-CBC key for the environment
 124  *
 125  * This function shall return 16-byte array containing AES-128 key used
 126  * to encrypt and decrypt the environment. This function must be overridden
 127  * by the implementer as otherwise the environment encryption will not
 128  * work.
 129  */
 130 __weak uint8_t *env_aes_cbc_get_key(void)
 131 {
 132         return NULL;
 133 }
 134
 135 static int env_aes_cbc_crypt(env_t *env, const int enc)
 136 {
 137         unsigned char *data = env->data;
 138         uint8_t *key;
 139         uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
 140         uint32_t aes_blocks;
 141
 142         key = env_aes_cbc_get_key();
 143         if (!key)
 144                 return -EINVAL;
 145
 146         /* First we expand the key. */
 147         aes_expand_key(key, key_exp);
 148
 149         /* Calculate the number of AES blocks to encrypt. */
 150         aes_blocks = ENV_SIZE / AES_KEY_LENGTH;
 151
 152         if (enc)
 153                 aes_cbc_encrypt_blocks(key_exp, data, data, aes_blocks);
 154         else
 155                 aes_cbc_decrypt_blocks(key_exp, data, data, aes_blocks);
 156
 157         return 0;
 158 }
 159 #else
 160 static inline int env_aes_cbc_crypt(env_t *env, const int enc)
 161 {
 162         return 0;
 163 }
 164 #endif
 165
 166 /*
 167  * Check if CRC is valid and (if yes) import the environment.
 168  * Note that "buf" may or may not be aligned.
 169  */
 170 int env_import(const char *buf, int check)
 171 {
 172         env_t *ep = (env_t *)buf;
 173         int ret;
 174
 175         if (check) {
 176                 uint32_t crc;
 177
 178                 memcpy(&crc, &ep->crc, sizeof(crc));
 179
 180                 if (crc32(0, ep->data, ENV_SIZE) != crc) {
 181                         set_default_env("!bad CRC");
 182                         return 0;
 183                 }
 184         }
 185
 186         /* Decrypt the env if desired. */
 187         ret = env_aes_cbc_crypt(ep, 0);
 188         if (ret) {
 189                 error("Failed to decrypt env!\n");
 190                 set_default_env("!import failed");
 191                 return ret;
 192         }
 193
 194         if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
 195                         0, NULL)) {
 196                 gd->flags |= GD_FLG_ENV_READY;
 197                 return 1;
 198         }
 199
 200         error("Cannot import environment: errno = %d\n", errno);
 201
 202         set_default_env("!import failed");
 203
 204         return 0;
 205 }
 206
 207 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 208 static unsigned char env_flags;
 209
 210 int env_import_redund(const char *buf1, const char *buf2)
 211 {
 212         int crc1_ok, crc2_ok;
 213         env_t *ep, *tmp_env1, *tmp_env2;
 214
 215         tmp_env1 = (env_t *)buf1;
 216         tmp_env2 = (env_t *)buf2;
 217
 218         crc1_ok = crc32(0, tmp_env1->data, ENV_SIZE) ==
 219                         tmp_env1->crc;
 220         crc2_ok = crc32(0, tmp_env2->data, ENV_SIZE) ==
 221                         tmp_env2->crc;
 222
 223         if (!crc1_ok && !crc2_ok) {
 224                 set_default_env("!bad CRC");
 225                 return 0;
 226         } else if (crc1_ok && !crc2_ok) {
 227                 gd->env_valid = 1;
 228         } else if (!crc1_ok && crc2_ok) {
 229                 gd->env_valid = 2;
 230         } else {
 231                 /* both ok - check serial */
 232                 if (tmp_env1->flags == 255 && tmp_env2->flags == 0)
 233                         gd->env_valid = 2;
 234                 else if (tmp_env2->flags == 255 && tmp_env1->flags == 0)
 235                         gd->env_valid = 1;
 236                 else if (tmp_env1->flags > tmp_env2->flags)
 237                         gd->env_valid = 1;
 238                 else if (tmp_env2->flags > tmp_env1->flags)
 239                         gd->env_valid = 2;
 240                 else /* flags are equal - almost impossible */
 241                         gd->env_valid = 1;
 242         }
 243
 244         if (gd->env_valid == 1)
 245                 ep = tmp_env1;
 246         else
 247                 ep = tmp_env2;
 248
 249         env_flags = ep->flags;
 250         return env_import((char *)ep, 0);
 251 }
 252 #endif /* CONFIG_SYS_REDUNDAND_ENVIRONMENT */
 253
 254 /* Export the environment and generate CRC for it. */
 255 int env_export(env_t *env_out)
 256 {
 257         char *res;
 258         ssize_t len;
 259         int ret;
 260
 261         res = (char *)env_out->data;
 262         len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
 263         if (len < 0) {
 264                 error("Cannot export environment: errno = %d\n", errno);
 265                 return 1;
 266         }
 267
 268         /* Encrypt the env if desired. */
 269         ret = env_aes_cbc_crypt(env_out, 1);
 270         if (ret)
 271                 return ret;
 272
 273         env_out->crc = crc32(0, env_out->data, ENV_SIZE);
 274
 275 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 276         env_out->flags = ++env_flags; /* increase the serial */
 277 #endif
 278
 279         return 0;
 280 }
 281
 282 void env_relocate(void)
 283 {
 284 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 285         env_reloc();
 286         env_htab.change_ok += gd->reloc_off;
 287 #endif
 288         if (gd->env_valid == 0) {
 289 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
 290                 /* Environment not changable */
 291                 set_default_env(NULL);
 292 #else
 293                 bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
 294                 set_default_env("!bad CRC");
 295 #endif
 296         } else {
 297                 env_relocate_spec();
 298         }
 299 }
 300
 301 #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
 302 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
 303 {
 304         ENTRY *match;
 305         int found, idx;
 306
 307         idx = 0;
 308         found = 0;
 309         cmdv[0] = NULL;
 310
 311         while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
 312                 int vallen = strlen(match->key) + 1;
 313
 314                 if (found >= maxv - 2 || bufsz < vallen)
 315                         break;
 316
 317                 cmdv[found++] = buf;
 318                 memcpy(buf, match->key, vallen);
 319                 buf += vallen;
 320                 bufsz -= vallen;
 321         }
 322
 323         qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
 324
 325         if (idx)
 326                 cmdv[found++] = "...";
 327
 328         cmdv[found] = NULL;
 329         return found;
 330 }
 331 #endif