common/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 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 uchar env_get_char_memory(int index)
  45 {
  46         return *env_get_addr(index);
  47 }
  48
  49 uchar env_get_char(int index)
  50 {
  51         /* if relocated to RAM */
  52         if (gd->flags & GD_FLG_RELOC)
  53                 return env_get_char_memory(index);
  54         else
  55                 return env_get_char_init(index);
  56 }
  57
  58 const uchar *env_get_addr(int index)
  59 {
  60         if (gd->env_valid)
  61                 return (uchar *)(gd->env_addr + index);
  62         else
  63                 return &default_environment[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 }
 127
 128
 129 /* [re]set individual variables to their value in the default environment */
 130 int set_default_vars(int nvars, char * const vars[])
 131 {
 132         /*
 133          * Special use-case: import from default environment
 134          * (and use \0 as a separator)
 135          */
 136         return himport_r(&env_htab, (const char *)default_environment,
 137                                 sizeof(default_environment), '\0',
 138                                 H_NOCLEAR | H_INTERACTIVE, 0, nvars, vars);
 139 }
 140
 141 #ifdef CONFIG_ENV_AES
 142 #include <aes.h>
 143 /**
 144  * env_aes_cbc_get_key() - Get AES-128-CBC key for the environment
 145  *
 146  * This function shall return 16-byte array containing AES-128 key used
 147  * to encrypt and decrypt the environment. This function must be overriden
 148  * by the implementer as otherwise the environment encryption will not
 149  * work.
 150  */
 151 __weak uint8_t *env_aes_cbc_get_key(void)
 152 {
 153         return NULL;
 154 }
 155
 156 static int env_aes_cbc_crypt(env_t *env, const int enc)
 157 {
 158         unsigned char *data = env->data;
 159         uint8_t *key;
 160         uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
 161         uint32_t aes_blocks;
 162
 163         key = env_aes_cbc_get_key();
 164         if (!key)
 165                 return -EINVAL;
 166
 167         /* First we expand the key. */
 168         aes_expand_key(key, key_exp);
 169
 170         /* Calculate the number of AES blocks to encrypt. */
 171         aes_blocks = ENV_SIZE / AES_KEY_LENGTH;
 172
 173         if (enc)
 174                 aes_cbc_encrypt_blocks(key_exp, data, data, aes_blocks);
 175         else
 176                 aes_cbc_decrypt_blocks(key_exp, data, data, aes_blocks);
 177
 178         return 0;
 179 }
 180 #else
 181 static inline int env_aes_cbc_crypt(env_t *env, const int enc)
 182 {
 183         return 0;
 184 }
 185 #endif
 186
 187 /*
 188  * Check if CRC is valid and (if yes) import the environment.
 189  * Note that "buf" may or may not be aligned.
 190  */
 191 int env_import(const char *buf, int check)
 192 {
 193         env_t *ep = (env_t *)buf;
 194         int ret;
 195
 196         if (check) {
 197                 uint32_t crc;
 198
 199                 memcpy(&crc, &ep->crc, sizeof(crc));
 200
 201                 if (crc32(0, ep->data, ENV_SIZE) != crc) {
 202                         set_default_env("!bad CRC");
 203                         return 0;
 204                 }
 205         }
 206
 207         /* Decrypt the env if desired. */
 208         ret = env_aes_cbc_crypt(ep, 0);
 209         if (ret) {
 210                 error("Failed to decrypt env!\n");
 211                 set_default_env("!import failed");
 212                 return ret;
 213         }
 214
 215         if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
 216                         0, NULL)) {
 217                 gd->flags |= GD_FLG_ENV_READY;
 218                 return 1;
 219         }
 220
 221         error("Cannot import environment: errno = %d\n", errno);
 222
 223         set_default_env("!import failed");
 224
 225         return 0;
 226 }
 227
 228 /* Emport the environment and generate CRC for it. */
 229 int env_export(env_t *env_out)
 230 {
 231         char *res;
 232         ssize_t len;
 233         int ret;
 234
 235         res = (char *)env_out->data;
 236         len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
 237         if (len < 0) {
 238                 error("Cannot export environment: errno = %d\n", errno);
 239                 return 1;
 240         }
 241
 242         /* Encrypt the env if desired. */
 243         ret = env_aes_cbc_crypt(env_out, 1);
 244         if (ret)
 245                 return ret;
 246
 247         env_out->crc = crc32(0, env_out->data, ENV_SIZE);
 248
 249         return 0;
 250 }
 251
 252 void env_relocate(void)
 253 {
 254 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 255         env_reloc();
 256         env_htab.change_ok += gd->reloc_off;
 257 #endif
 258         if (gd->env_valid == 0) {
 259 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
 260                 /* Environment not changable */
 261                 set_default_env(NULL);
 262 #else
 263                 bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
 264                 set_default_env("!bad CRC");
 265 #endif
 266         } else {
 267                 env_relocate_spec();
 268         }
 269 }
 270
 271 #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
 272 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
 273 {
 274         ENTRY *match;
 275         int found, idx;
 276
 277         idx = 0;
 278         found = 0;
 279         cmdv[0] = NULL;
 280
 281         while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
 282                 int vallen = strlen(match->key) + 1;
 283
 284                 if (found >= maxv - 2 || bufsz < vallen)
 285                         break;
 286
 287                 cmdv[found++] = buf;
 288                 memcpy(buf, match->key, vallen);
 289                 buf += vallen;
 290                 bufsz -= vallen;
 291         }
 292
 293         qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
 294
 295         if (idx)
 296                 cmdv[found++] = "...";
 297
 298         cmdv[found] = NULL;
 299         return found;
 300 }
 301 #endif