aes: add a define for the size of a block

In the code, we use the size of the key for the
size of the block. It's true when the key is 128 bits,
but it become false for key of 192 bits and 256 bits.
So to prepare the support of aes192  and 256,
we introduce a constant for the iaes block size.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/cmd/aes.c b/cmd/aes.c
index 8c61cee8e89b25db485c1e8729d14d5aea5ecd48..24b0256a7623b8c283e5ecea6de5a1fc699695ce 100644 (file)
--- a/cmd/aes.c
+++ b/cmd/aes.c
@@ -56,7 +56,7 @@ static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
        aes_expand_key(key_ptr, key_exp);
 
        /* Calculate the number of AES blocks to encrypt. */
-       aes_blocks = DIV_ROUND_UP(len, AES_KEY_LENGTH);
+       aes_blocks = DIV_ROUND_UP(len, AES_BLOCK_LENGTH);
 
        if (enc)
                aes_cbc_encrypt_blocks(key_exp, iv_ptr, src_ptr, dst_ptr,

diff --git a/include/uboot_aes.h b/include/uboot_aes.h
index 2fda384e3b79a5de3766a446ae52fa51ed977a8a..1ae3ac9cb22f54596ae025932d89dba3bcd08be7 100644 (file)
--- a/include/uboot_aes.h
+++ b/include/uboot_aes.h
@@ -18,7 +18,7 @@ typedef unsigned int u32;
  * AES encryption library, with small code size, supporting only 128-bit AES
  *
  * AES is a stream cipher which works a block at a time, with each block
- * in this case being AES_KEY_LENGTH bytes.
+ * in this case being AES_BLOCK_LENGTH bytes.
  */
 
 enum {
@@ -28,6 +28,7 @@ enum {
 
        AES_KEY_LENGTH  = 128 / 8,
        AES_EXPAND_KEY_LENGTH   = 4 * AES_STATECOLS * (AES_ROUNDS + 1),
+       AES_BLOCK_LENGTH        = 128 / 8,
 };
 
 /**
@@ -62,7 +63,7 @@ void aes_decrypt(u8 *in, u8 *expkey, u8 *out);
 /**
  * Apply chain data to the destination using EOR
  *
- * Each array is of length AES_KEY_LENGTH.
+ * Each array is of length AES_BLOCK_LENGTH.
  *
  * @cbc_chain_data     Chain data
  * @src                        Source data

diff --git a/lib/aes.c b/lib/aes.c
index a12a19208433acf9ee7ab0991a37124af86819ee..cfa57b681c6425758b29986bb97576783b91b9d2 100644 (file)
--- a/lib/aes.c
+++ b/lib/aes.c
@@ -596,62 +596,62 @@ void aes_apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst)
 {
        int i;
 
-       for (i = 0; i < AES_KEY_LENGTH; i++)
+       for (i = 0; i < AES_BLOCK_LENGTH; i++)
                *dst++ = *src++ ^ *cbc_chain_data++;
 }
 
 void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
                            u32 num_aes_blocks)
 {
-       u8 tmp_data[AES_KEY_LENGTH];
+       u8 tmp_data[AES_BLOCK_LENGTH];
        u8 *cbc_chain_data = iv;
        u32 i;
 
        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);
+               debug_print_vector("AES Src", AES_BLOCK_LENGTH, src);
 
                /* Apply the chain data */
                aes_apply_cbc_chain_data(cbc_chain_data, src, tmp_data);
-               debug_print_vector("AES Xor", AES_KEY_LENGTH, tmp_data);
+               debug_print_vector("AES Xor", AES_BLOCK_LENGTH, tmp_data);
 
                /* Encrypt the AES block */
                aes_encrypt(tmp_data, key_exp, dst);
-               debug_print_vector("AES Dst", AES_KEY_LENGTH, dst);
+               debug_print_vector("AES Dst", AES_BLOCK_LENGTH, dst);
 
                /* Update pointers for next loop. */
                cbc_chain_data = dst;
-               src += AES_KEY_LENGTH;
-               dst += AES_KEY_LENGTH;
+               src += AES_BLOCK_LENGTH;
+               dst += AES_BLOCK_LENGTH;
        }
 }
 
 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];
+       u8 tmp_data[AES_BLOCK_LENGTH], tmp_block[AES_BLOCK_LENGTH];
        /* Convenient array of 0's for IV */
-       u8 cbc_chain_data[AES_KEY_LENGTH];
+       u8 cbc_chain_data[AES_BLOCK_LENGTH];
        u32 i;
 
-       memcpy(cbc_chain_data, iv, AES_KEY_LENGTH);
+       memcpy(cbc_chain_data, iv, AES_BLOCK_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);
+               debug_print_vector("AES Src", AES_BLOCK_LENGTH, src);
 
-               memcpy(tmp_block, src, AES_KEY_LENGTH);
+               memcpy(tmp_block, src, AES_BLOCK_LENGTH);
 
                /* Decrypt the AES block */
                aes_decrypt(src, key_exp, tmp_data);
-               debug_print_vector("AES Xor", AES_KEY_LENGTH, tmp_data);
+               debug_print_vector("AES Xor", AES_BLOCK_LENGTH, tmp_data);
 
                /* Apply the chain data */
                aes_apply_cbc_chain_data(cbc_chain_data, tmp_data, dst);
-               debug_print_vector("AES Dst", AES_KEY_LENGTH, dst);
+               debug_print_vector("AES Dst", AES_BLOCK_LENGTH, dst);
 
                /* Update pointers for next loop. */
-               memcpy(cbc_chain_data, tmp_block, AES_KEY_LENGTH);
-               src += AES_KEY_LENGTH;
-               dst += AES_KEY_LENGTH;
+               memcpy(cbc_chain_data, tmp_block, AES_BLOCK_LENGTH);
+               src += AES_BLOCK_LENGTH;
+               dst += AES_BLOCK_LENGTH;
        }
 }