aes: Allow non-zero initialization vector

AES encryption in CBC mode, in most cases, must be used with random
initialization vector. Using the same key and initialization vector several
times is weak and must be avoided.

Added iv parameter to the aes_cbc_encrypt_blocks and aes_cbc_decrypt_blocks
functions for passing initialization vector.

Command 'aes' now also require the initialization vector parameter.

Signed-off-by: Andrey Mozzhuhin <amozzhuhin@yandex.ru>

diff --git a/arch/arm/mach-tegra/tegra20/crypto.c b/arch/arm/mach-tegra/tegra20/crypto.c
index eae79217d443519b815c41c2f2dbb990a8cc0ab0..58d6662f6d4b8b231bbc0ae487429ee6e37ce072 100644 (file)
--- a/arch/arm/mach-tegra/tegra20/crypto.c
+++ b/arch/arm/mach-tegra/tegra20/crypto.c
@@ -50,6 +50,7 @@ static void sign_object(u8 *key, u8 *key_schedule, u8 *src, u8 *dst,
                        u32 num_aes_blocks)
 {
        u8 tmp_data[AES_KEY_LENGTH];
+       u8 iv[AES_KEY_LENGTH] = {0};
        u8 left[AES_KEY_LENGTH];
        u8 k1[AES_KEY_LENGTH];
        u8 *cbc_chain_data;
@@ -61,7 +62,7 @@ static void sign_object(u8 *key, u8 *key_schedule, u8 *src, u8 *dst,
        for (i = 0; i < AES_KEY_LENGTH; i++)
                tmp_data[i] = 0;
 
-       aes_cbc_encrypt_blocks(key_schedule, tmp_data, left, 1);
+       aes_cbc_encrypt_blocks(key_schedule, iv, tmp_data, left, 1);
 
        left_shift_vector(left, k1, sizeof(left));
 
@@ -102,6 +103,7 @@ static int encrypt_and_sign(u8 *key, enum security_op oper, u8 *src,
 {
        u32 num_aes_blocks;
        u8 key_schedule[AES_EXPAND_KEY_LENGTH];
+       u8 iv[AES_KEY_LENGTH] = {0};
 
        debug("encrypt_and_sign: length = %d\n", length);
 
@@ -116,7 +118,8 @@ static int encrypt_and_sign(u8 *key, enum security_op oper, u8 *src,
        if (oper & SECURITY_ENCRYPT) {
                /* Perform this in place, resulting in src being encrypted. */
                debug("encrypt_and_sign: begin encryption\n");
-               aes_cbc_encrypt_blocks(key_schedule, src, src, num_aes_blocks);
+               aes_cbc_encrypt_blocks(key_schedule, iv, src, src,
+                                      num_aes_blocks);
                debug("encrypt_and_sign: end encryption\n");
        }
 

diff --git a/cmd/aes.c b/cmd/aes.c
index ee1ae13c06ece13827475c42fb79aaeeed023133..9d1a740beeadbb5b3861364bf0a8de7720d3edf6 100644 (file)
--- a/cmd/aes.c
+++ b/cmd/aes.c
@@ -28,13 +28,13 @@ DECLARE_GLOBAL_DATA_PTR;
  */
 static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 {
-       uint32_t key_addr, src_addr, dst_addr, len;
-       uint8_t *key_ptr, *src_ptr, *dst_ptr;
+       uint32_t key_addr, iv_addr, src_addr, dst_addr, len;
+       uint8_t *key_ptr, *iv_ptr, *src_ptr, *dst_ptr;
        uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
        uint32_t aes_blocks;
        int enc;
 
-       if (argc != 6)
+       if (argc != 7)
                return CMD_RET_USAGE;
 
        if (!strncmp(argv[1], "enc", 3))
@@ -45,11 +45,13 @@ static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
                return CMD_RET_USAGE;
 
        key_addr = simple_strtoul(argv[2], NULL, 16);
-       src_addr = simple_strtoul(argv[3], NULL, 16);
-       dst_addr = simple_strtoul(argv[4], NULL, 16);
-       len = simple_strtoul(argv[5], NULL, 16);
+       iv_addr = simple_strtoul(argv[3], NULL, 16);
+       src_addr = simple_strtoul(argv[4], NULL, 16);
+       dst_addr = simple_strtoul(argv[5], NULL, 16);
+       len = simple_strtoul(argv[6], NULL, 16);
 
        key_ptr = (uint8_t *)key_addr;
+       iv_ptr = (uint8_t *)iv_addr;
        src_ptr = (uint8_t *)src_addr;
        dst_ptr = (uint8_t *)dst_addr;
 
@@ -60,9 +62,11 @@ static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
        aes_blocks = DIV_ROUND_UP(len, AES_KEY_LENGTH);
 
        if (enc)
-               aes_cbc_encrypt_blocks(key_exp, src_ptr, dst_ptr, aes_blocks);
+               aes_cbc_encrypt_blocks(key_exp, iv_ptr, src_ptr, dst_ptr,
+                                      aes_blocks);
        else
-               aes_cbc_decrypt_blocks(key_exp, src_ptr, dst_ptr, aes_blocks);
+               aes_cbc_decrypt_blocks(key_exp, iv_ptr, src_ptr, dst_ptr,
+                                      aes_blocks);
 
        return 0;
 }
@@ -70,20 +74,22 @@ static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 /***************************************************/
 #ifdef CONFIG_SYS_LONGHELP
 static char aes_help_text[] =
-       "enc key src dst len - Encrypt block of data $len bytes long\n"
-       "                          at address $src using a key at address\n"
-       "                          $key and store the result at address\n"
-       "                          $dst. The $len size must be multiple of\n"
-       "                          16 bytes and $key must be 16 bytes long.\n"
-       "aes dec key src dst len - Decrypt block of data $len bytes long\n"
-       "                          at address $src using a key at address\n"
-       "                          $key and store the result at address\n"
-       "                          $dst. The $len size must be multiple of\n"
-       "                          16 bytes and $key must be 16 bytes long.";
+       "enc key iv src dst len - Encrypt block of data $len bytes long\n"
+       "                             at address $src using a key at address\n"
+       "                             $key with initialization vector at address\n"
+       "                             $iv. Store the result at address $dst.\n"
+       "                             The $len size must be multiple of 16 bytes.\n"
+       "                             The $key and $iv must be 16 bytes long.\n"
+       "aes dec key iv src dst len - Decrypt block of data $len bytes long\n"
+       "                             at address $src using a key at address\n"
+       "                             $key with initialization vector at address\n"
+       "                             $iv. Store the result at address $dst.\n"
+       "                             The $len size must be multiple of 16 bytes.\n"
+       "                             The $key and $iv must be 16 bytes long.";
 #endif
 
 U_BOOT_CMD(
-       aes, 6, 1, do_aes,
+       aes, 7, 1, do_aes,
        "AES 128 CBC encryption",
        aes_help_text
 );

diff --git a/include/uboot_aes.h b/include/uboot_aes.h
index 6315c02aa93d9fc6a4cda3f52f4912c8ebe2e5a0..b651bca1c95c532dacf43128852ba80fbd541204 100644 (file)
--- a/include/uboot_aes.h
+++ b/include/uboot_aes.h
@@ -75,20 +75,24 @@ void aes_apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst);
  * aes_cbc_encrypt_blocks() - Encrypt multiple blocks of data with AES CBC.
  *
  * @key_exp            Expanded key to use
+ * @iv                 Initialization vector
  * @src                        Source data to encrypt
  * @dst                        Destination buffer
  * @num_aes_blocks     Number of AES blocks to encrypt
  */
-void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *src, u8 *dst, u32 num_aes_blocks);
+void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
+                           u32 num_aes_blocks);
 
 /**
  * Decrypt multiple blocks of data with AES CBC.
  *
  * @key_exp            Expanded key to use
+ * @iv                 Initialization vector
  * @src                        Source data to decrypt
  * @dst                        Destination buffer
  * @num_aes_blocks     Number of AES blocks to decrypt
  */
-void aes_cbc_decrypt_blocks(u8 *key_exp, u8 *src, u8 *dst, u32 num_aes_blocks);
+void aes_cbc_decrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
+                           u32 num_aes_blocks);
 
 #endif /* _AES_REF_H_ */

diff --git a/lib/aes.c b/lib/aes.c
index d6144e61d6ef089a8138cc6f33a3560e6b44c2ba..2b0849c7e04ed46983035c485b2795b788a1f9e6 100644 (file)
--- a/lib/aes.c
+++ b/lib/aes.c
@@ -601,12 +601,11 @@ void aes_apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst)
                *dst++ = *src++ ^ *cbc_chain_data++;
 }
 
-void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *src, u8 *dst, u32 num_aes_blocks)
+void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
+                           u32 num_aes_blocks)
 {
-       u8 zero_key[AES_KEY_LENGTH] = { 0 };
        u8 tmp_data[AES_KEY_LENGTH];
-       /* Convenient array of 0's for IV */
-       u8 *cbc_chain_data = zero_key;
+       u8 *cbc_chain_data = iv;
        u32 i;
 
        for (i = 0; i < num_aes_blocks; i++) {
@@ -628,13 +627,15 @@ void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *src, u8 *dst, u32 num_aes_blocks)
        }
 }
 
-void aes_cbc_decrypt_blocks(u8 *key_exp, u8 *src, u8 *dst, u32 num_aes_blocks)
+void aes_cbc_decrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
+                           u32 num_aes_blocks)
 {
        u8 tmp_data[AES_KEY_LENGTH], tmp_block[AES_KEY_LENGTH];
        /* Convenient array of 0's for IV */
-       u8 cbc_chain_data[AES_KEY_LENGTH] = { 0 };
+       u8 cbc_chain_data[AES_KEY_LENGTH];
        u32 i;
 
+       memcpy(cbc_chain_data, iv, AES_KEY_LENGTH);
        for (i = 0; i < num_aes_blocks; i++) {
                debug("encrypt_object: block %d of %d\n", i, num_aes_blocks);
                debug_print_vector("AES Src", AES_KEY_LENGTH, src);