cmd/aes.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2014 Marek Vasut <marex@denx.de>
   4  *
   5  * Command for en/de-crypting block of memory with AES-[128/192/256]-CBC cipher.
   6  */
   7
   8 #include <common.h>
   9 #include <command.h>
  10 #include <uboot_aes.h>
  11 #include <malloc.h>
  12 #include <asm/byteorder.h>
  13 #include <linux/compiler.h>
  14 #include <mapmem.h>
  15
  16 u32 aes_get_key_len(char *command)
  17 {
  18         u32 key_len = AES128_KEY_LENGTH;
  19
  20         if (!strcmp(command, "aes.192"))
  21                 key_len = AES192_KEY_LENGTH;
  22         else if (!strcmp(command, "aes.256"))
  23                 key_len = AES256_KEY_LENGTH;
  24
  25         return key_len;
  26 }
  27
  28 /**
  29  * do_aes() - Handle the "aes" command-line command
  30  * @cmdtp:      Command data struct pointer
  31  * @flag:       Command flag
  32  * @argc:       Command-line argument count
  33  * @argv:       Array of command-line arguments
  34  *
  35  * Returns zero on success, CMD_RET_USAGE in case of misuse and negative
  36  * on error.
  37  */
  38 static int do_aes(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
  39 {
  40         uint32_t key_addr, iv_addr, src_addr, dst_addr, len;
  41         uint8_t *key_ptr, *iv_ptr, *src_ptr, *dst_ptr;
  42         u8 key_exp[AES256_EXPAND_KEY_LENGTH];
  43         u32 aes_blocks, key_len;
  44         int enc;
  45
  46         if (argc != 7)
  47                 return CMD_RET_USAGE;
  48
  49         key_len = aes_get_key_len(argv[0]);
  50
  51         if (!strncmp(argv[1], "enc", 3))
  52                 enc = 1;
  53         else if (!strncmp(argv[1], "dec", 3))
  54                 enc = 0;
  55         else
  56                 return CMD_RET_USAGE;
  57
  58         key_addr = hextoul(argv[2], NULL);
  59         iv_addr = hextoul(argv[3], NULL);
  60         src_addr = hextoul(argv[4], NULL);
  61         dst_addr = hextoul(argv[5], NULL);
  62         len = hextoul(argv[6], NULL);
  63
  64         key_ptr = (uint8_t *)map_sysmem(key_addr, key_len);
  65         iv_ptr = (uint8_t *)map_sysmem(iv_addr, 128 / 8);
  66         src_ptr = (uint8_t *)map_sysmem(src_addr, len);
  67         dst_ptr = (uint8_t *)map_sysmem(dst_addr, len);
  68
  69         /* First we expand the key. */
  70         aes_expand_key(key_ptr, key_len, key_exp);
  71
  72         /* Calculate the number of AES blocks to encrypt. */
  73         aes_blocks = DIV_ROUND_UP(len, AES_BLOCK_LENGTH);
  74
  75         if (enc)
  76                 aes_cbc_encrypt_blocks(key_len, key_exp, iv_ptr, src_ptr,
  77                                        dst_ptr, aes_blocks);
  78         else
  79                 aes_cbc_decrypt_blocks(key_len, key_exp, iv_ptr, src_ptr,
  80                                        dst_ptr, aes_blocks);
  81
  82         unmap_sysmem(key_ptr);
  83         unmap_sysmem(iv_ptr);
  84         unmap_sysmem(src_ptr);
  85         unmap_sysmem(dst_ptr);
  86
  87         return 0;
  88 }
  89
  90 /***************************************************/
  91 U_BOOT_LONGHELP(aes,
  92         "[.128,.192,.256] enc key iv src dst len - Encrypt block of data $len bytes long\n"
  93         "                             at address $src using a key at address\n"
  94         "                             $key with initialization vector at address\n"
  95         "                             $iv. Store the result at address $dst.\n"
  96         "                             The $len size must be multiple of 16 bytes.\n"
  97         "                             The $key and $iv must be 16 bytes long.\n"
  98         "aes [.128,.192,.256] dec key iv src dst len - Decrypt block of data $len bytes long\n"
  99         "                             at address $src using a key at address\n"
 100         "                             $key with initialization vector at address\n"
 101         "                             $iv. Store the result at address $dst.\n"
 102         "                             The $len size must be multiple of 16 bytes.\n"
 103         "                             The $key and $iv must be 16 bytes long.");
 104
 105 U_BOOT_CMD(
 106         aes, 7, 1, do_aes,
 107         "AES 128/192/256 CBC encryption",
 108         aes_help_text
 109 );