cmd/aes.c

   1 /*
   2  * Copyright (C) 2014 Marek Vasut <marex@denx.de>
   3  *
   4  * Command for en/de-crypting block of memory with AES-128-CBC cipher.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <command.h>
  11 #include <environment.h>
  12 #include <aes.h>
  13 #include <malloc.h>
  14 #include <asm/byteorder.h>
  15 #include <linux/compiler.h>
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 /**
  20  * do_aes() - Handle the "aes" command-line command
  21  * @cmdtp:      Command data struct pointer
  22  * @flag:       Command flag
  23  * @argc:       Command-line argument count
  24  * @argv:       Array of command-line arguments
  25  *
  26  * Returns zero on success, CMD_RET_USAGE in case of misuse and negative
  27  * on error.
  28  */
  29 static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
  30 {
  31         uint32_t key_addr, src_addr, dst_addr, len;
  32         uint8_t *key_ptr, *src_ptr, *dst_ptr;
  33         uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
  34         uint32_t aes_blocks;
  35         int enc;
  36
  37         if (argc != 6)
  38                 return CMD_RET_USAGE;
  39
  40         if (!strncmp(argv[1], "enc", 3))
  41                 enc = 1;
  42         else if (!strncmp(argv[1], "dec", 3))
  43                 enc = 0;
  44         else
  45                 return CMD_RET_USAGE;
  46
  47         key_addr = simple_strtoul(argv[2], NULL, 16);
  48         src_addr = simple_strtoul(argv[3], NULL, 16);
  49         dst_addr = simple_strtoul(argv[4], NULL, 16);
  50         len = simple_strtoul(argv[5], NULL, 16);
  51
  52         key_ptr = (uint8_t *)key_addr;
  53         src_ptr = (uint8_t *)src_addr;
  54         dst_ptr = (uint8_t *)dst_addr;
  55
  56         /* First we expand the key. */
  57         aes_expand_key(key_ptr, key_exp);
  58
  59         /* Calculate the number of AES blocks to encrypt. */
  60         aes_blocks = DIV_ROUND_UP(len, AES_KEY_LENGTH);
  61
  62         if (enc)
  63                 aes_cbc_encrypt_blocks(key_exp, src_ptr, dst_ptr, aes_blocks);
  64         else
  65                 aes_cbc_decrypt_blocks(key_exp, src_ptr, dst_ptr, aes_blocks);
  66
  67         return 0;
  68 }
  69
  70 /***************************************************/
  71 #ifdef CONFIG_SYS_LONGHELP
  72 static char aes_help_text[] =
  73         "enc key src dst len - Encrypt block of data $len bytes long\n"
  74         "                          at address $src using a key at address\n"
  75         "                          $key and store the result at address\n"
  76         "                          $dst. The $len size must be multiple of\n"
  77         "                          16 bytes and $key must be 16 bytes long.\n"
  78         "aes dec key src dst len - Decrypt block of data $len bytes long\n"
  79         "                          at address $src using a key at address\n"
  80         "                          $key and store the result at address\n"
  81         "                          $dst. The $len size must be multiple of\n"
  82         "                          16 bytes and $key must be 16 bytes long.";
  83 #endif
  84
  85 U_BOOT_CMD(
  86         aes, 6, 1, do_aes,
  87         "AES 128 CBC encryption",
  88         aes_help_text
  89 );