aes: add support of aes192 and aes256

Until now, we only support aes128. This commit add the support
of aes192 and aes256.

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

1 files changed, 54 insertions, 23 deletions

diff --git a/lib/aes.c b/lib/aes.c
index cfa57b6..ce53c9f 100644
--- a/lib/aes.c
+++ b/lib/aes.c
@@ -508,50 +508,79 @@ static u8 rcon[11] = {
 	0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
 };
 
+static u32 aes_get_rounds(u32 key_len)
+{
+	u32 rounds = AES128_ROUNDS;
+
+	if (key_len == AES192_KEY_LENGTH)
+		rounds = AES192_ROUNDS;
+	else if (key_len == AES256_KEY_LENGTH)
+		rounds = AES256_ROUNDS;
+
+	return rounds;
+}
+
+static u32 aes_get_keycols(u32 key_len)
+{
+	u32 keycols = AES128_KEYCOLS;
+
+	if (key_len == AES192_KEY_LENGTH)
+		keycols = AES192_KEYCOLS;
+	else if (key_len == AES256_KEY_LENGTH)
+		keycols = AES256_KEYCOLS;
+
+	return keycols;
+}
+
 /* produce AES_STATECOLS bytes for each round */
-void aes_expand_key(u8 *key, u8 *expkey)
+void aes_expand_key(u8 *key, u32 key_len, u8 *expkey)
 {
 	u8 tmp0, tmp1, tmp2, tmp3, tmp4;
-	u32 idx;
+	u32 idx, aes_rounds, aes_keycols;
 
-	memcpy(expkey, key, AES_KEYCOLS * 4);
+	aes_rounds = aes_get_rounds(key_len);
+	aes_keycols = aes_get_keycols(key_len);
 
-	for (idx = AES_KEYCOLS; idx < AES_STATECOLS * (AES_ROUNDS + 1); idx++) {
+	memcpy(expkey, key, key_len);
+
+	for (idx = aes_keycols; idx < AES_STATECOLS * (aes_rounds + 1); idx++) {
 		tmp0 = expkey[4*idx - 4];
 		tmp1 = expkey[4*idx - 3];
 		tmp2 = expkey[4*idx - 2];
 		tmp3 = expkey[4*idx - 1];
-		if (!(idx % AES_KEYCOLS)) {
+		if (!(idx % aes_keycols)) {
 			tmp4 = tmp3;
 			tmp3 = sbox[tmp0];
-			tmp0 = sbox[tmp1] ^ rcon[idx / AES_KEYCOLS];
+			tmp0 = sbox[tmp1] ^ rcon[idx / aes_keycols];
 			tmp1 = sbox[tmp2];
 			tmp2 = sbox[tmp4];
-		} else if ((AES_KEYCOLS > 6) && (idx % AES_KEYCOLS == 4)) {
+		} else if ((aes_keycols > 6) && (idx % aes_keycols == 4)) {
 			tmp0 = sbox[tmp0];
 			tmp1 = sbox[tmp1];
 			tmp2 = sbox[tmp2];
 			tmp3 = sbox[tmp3];
 		}
 
-		expkey[4*idx+0] = expkey[4*idx - 4*AES_KEYCOLS + 0] ^ tmp0;
-		expkey[4*idx+1] = expkey[4*idx - 4*AES_KEYCOLS + 1] ^ tmp1;
-		expkey[4*idx+2] = expkey[4*idx - 4*AES_KEYCOLS + 2] ^ tmp2;
-		expkey[4*idx+3] = expkey[4*idx - 4*AES_KEYCOLS + 3] ^ tmp3;
+		expkey[4*idx+0] = expkey[4*idx - 4*aes_keycols + 0] ^ tmp0;
+		expkey[4*idx+1] = expkey[4*idx - 4*aes_keycols + 1] ^ tmp1;
+		expkey[4*idx+2] = expkey[4*idx - 4*aes_keycols + 2] ^ tmp2;
+		expkey[4*idx+3] = expkey[4*idx - 4*aes_keycols + 3] ^ tmp3;
 	}
 }
 
 /* encrypt one 128 bit block */
-void aes_encrypt(u8 *in, u8 *expkey, u8 *out)
+void aes_encrypt(u32 key_len, u8 *in, u8 *expkey, u8 *out)
 {
 	u8 state[AES_STATECOLS * 4];
-	u32 round;
+	u32 round, aes_rounds;
+
+	aes_rounds = aes_get_rounds(key_len);
 
 	memcpy(state, in, AES_STATECOLS * 4);
 	add_round_key((u32 *)state, (u32 *)expkey);
 
-	for (round = 1; round < AES_ROUNDS + 1; round++) {
-		if (round < AES_ROUNDS)
+	for (round = 1; round < aes_rounds + 1; round++) {
+		if (round < aes_rounds)
 			mix_sub_columns(state);
 		else
 			shift_rows(state);
@@ -563,18 +592,20 @@ void aes_encrypt(u8 *in, u8 *expkey, u8 *out)
 	memcpy(out, state, sizeof(state));
 }
 
-void aes_decrypt(u8 *in, u8 *expkey, u8 *out)
+void aes_decrypt(u32 key_len, u8 *in, u8 *expkey, u8 *out)
 {
 	u8 state[AES_STATECOLS * 4];
-	int round;
+	int round, aes_rounds;
+
+	aes_rounds = aes_get_rounds(key_len);
 
 	memcpy(state, in, sizeof(state));
 
 	add_round_key((u32 *)state,
-		      (u32 *)expkey + AES_ROUNDS * AES_STATECOLS);
+		      (u32 *)expkey + aes_rounds * AES_STATECOLS);
 	inv_shift_rows(state);
 
-	for (round = AES_ROUNDS; round--; ) {
+	for (round = aes_rounds; round--; ) {
 		add_round_key((u32 *)state,
 			      (u32 *)expkey + round * AES_STATECOLS);
 		if (round)
@@ -600,7 +631,7 @@ 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 *iv, u8 *src, u8 *dst,
+void aes_cbc_encrypt_blocks(u32 key_len, u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
 			    u32 num_aes_blocks)
 {
 	u8 tmp_data[AES_BLOCK_LENGTH];
@@ -616,7 +647,7 @@ void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
 		debug_print_vector("AES Xor", AES_BLOCK_LENGTH, tmp_data);
 
 		/* Encrypt the AES block */
-		aes_encrypt(tmp_data, key_exp, dst);
+		aes_encrypt(key_len, tmp_data, key_exp, dst);
 		debug_print_vector("AES Dst", AES_BLOCK_LENGTH, dst);
 
 		/* Update pointers for next loop. */
@@ -626,7 +657,7 @@ void aes_cbc_encrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
 	}
 }
 
-void aes_cbc_decrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
+void aes_cbc_decrypt_blocks(u32 key_len, u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
 			    u32 num_aes_blocks)
 {
 	u8 tmp_data[AES_BLOCK_LENGTH], tmp_block[AES_BLOCK_LENGTH];
@@ -642,7 +673,7 @@ void aes_cbc_decrypt_blocks(u8 *key_exp, u8 *iv, u8 *src, u8 *dst,
 		memcpy(tmp_block, src, AES_BLOCK_LENGTH);
 
 		/* Decrypt the AES block */
-		aes_decrypt(src, key_exp, tmp_data);
+		aes_decrypt(key_len, src, key_exp, tmp_data);
 		debug_print_vector("AES Xor", AES_BLOCK_LENGTH, tmp_data);
 
 		/* Apply the chain data */