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>

1 files changed, 25 insertions, 19 deletions

diff --git a/cmd/aes.c b/cmd/aes.c
index ee1ae13c06..9d1a740bee 100644
--- 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
 );