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         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 <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 overriden
 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 /* Emport the environment and generate CRC for it. */
 230 int env_export(env_t *env_out)
 231 {
 232         char *res;
 233         ssize_t len;
 234         int ret;
 235
 236         res = (char *)env_out->data;
 237         len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
 238         if (len < 0) {
 239                 error("Cannot export environment: errno = %d\n", errno);
 240                 return 1;
 241         }
 242
 243         /* Encrypt the env if desired. */
 244         ret = env_aes_cbc_crypt(env_out, 1);
 245         if (ret)
 246                 return ret;
 247
 248         env_out->crc = crc32(0, env_out->data, ENV_SIZE);
 249
 250         return 0;
 251 }
 252
 253 void env_relocate(void)
 254 {
 255 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 256         env_reloc();
 257         env_htab.change_ok += gd->reloc_off;
 258 #endif
 259         if (gd->env_valid == 0) {
 260 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
 261                 /* Environment not changable */
 262                 set_default_env(NULL);
 263 #else
 264                 bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
 265                 set_default_env("!bad CRC");
 266 #endif
 267         } else {
 268                 env_relocate_spec();
 269         }
 270 }
 271
 272 #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
 273 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
 274 {
 275         ENTRY *match;
 276         int found, idx;
 277
 278         idx = 0;
 279         found = 0;
 280         cmdv[0] = NULL;
 281
 282         while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
 283                 int vallen = strlen(match->key) + 1;
 284
 285                 if (found >= maxv - 2 || bufsz < vallen)
 286                         break;
 287
 288                 cmdv[found++] = buf;
 289                 memcpy(buf, match->key, vallen);
 290                 buf += vallen;
 291                 bufsz -= vallen;
 292         }
 293
 294         qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
 295
 296         if (idx)
 297                 cmdv[found++] = "...";
 298
 299         cmdv[found] = NULL;
 300         return found;
 301 }
 302 #endif