Fix AES block size handling for internal cipher

AES uses the same 128-bit block size with 128, 192, 256 bit keys, so use
the fixed block size definition instead of trying to dynamically set the
block size based on key length. This fixes use of 192-bit and 256-bit
AES keys with crypto_cipher_*() API when using the internal AES
implementation.

Signed-hostap: Jouni Malinen <j@w1.fi>

src/crypto/crypto_internal-cipher.c

@@ -24,7 +24,6 @@ struct crypto_cipher {
 		} rc4;
 		struct {
 			u8 cbc[32];
-			size_t block_size;
 			void *ctx_enc;
 			void *ctx_dec;
 		} aes;
@@ -63,10 +62,6 @@ struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
 		os_memcpy(ctx->u.rc4.key, key, key_len);
 		break;
 	case CRYPTO_CIPHER_ALG_AES:
-		if (key_len > sizeof(ctx->u.aes.cbc)) {
-			os_free(ctx);
-			return NULL;
-		}
 		ctx->u.aes.ctx_enc = aes_encrypt_init(key, key_len);
 		if (ctx->u.aes.ctx_enc == NULL) {
 			os_free(ctx);
@@ -78,8 +73,7 @@ struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
 			os_free(ctx);
 			return NULL;
 		}
-		ctx->u.aes.block_size = key_len;
-		os_memcpy(ctx->u.aes.cbc, iv, ctx->u.aes.block_size);
+		os_memcpy(ctx->u.aes.cbc, iv, AES_BLOCK_SIZE);
 		break;
 	case CRYPTO_CIPHER_ALG_3DES:
 		if (key_len != 24) {
@@ -120,18 +114,17 @@ int crypto_cipher_encrypt(struct crypto_cipher *ctx, const u8 *plain,
 		ctx->u.rc4.used_bytes += len;
 		break;
 	case CRYPTO_CIPHER_ALG_AES:
-		if (len % ctx->u.aes.block_size)
+		if (len % AES_BLOCK_SIZE)
 			return -1;
-		blocks = len / ctx->u.aes.block_size;
+		blocks = len / AES_BLOCK_SIZE;
 		for (i = 0; i < blocks; i++) {
-			for (j = 0; j < ctx->u.aes.block_size; j++)
+			for (j = 0; j < AES_BLOCK_SIZE; j++)
 				ctx->u.aes.cbc[j] ^= plain[j];
 			aes_encrypt(ctx->u.aes.ctx_enc, ctx->u.aes.cbc,
 				    ctx->u.aes.cbc);
-			os_memcpy(crypt, ctx->u.aes.cbc,
-				  ctx->u.aes.block_size);
-			plain += ctx->u.aes.block_size;
-			crypt += ctx->u.aes.block_size;
+			os_memcpy(crypt, ctx->u.aes.cbc, AES_BLOCK_SIZE);
+			plain += AES_BLOCK_SIZE;
+			crypt += AES_BLOCK_SIZE;
 		}
 		break;
 	case CRYPTO_CIPHER_ALG_3DES:
@@ -185,17 +178,17 @@ int crypto_cipher_decrypt(struct crypto_cipher *ctx, const u8 *crypt,
 		ctx->u.rc4.used_bytes += len;
 		break;
 	case CRYPTO_CIPHER_ALG_AES:
-		if (len % ctx->u.aes.block_size)
+		if (len % AES_BLOCK_SIZE)
 			return -1;
-		blocks = len / ctx->u.aes.block_size;
+		blocks = len / AES_BLOCK_SIZE;
 		for (i = 0; i < blocks; i++) {
-			os_memcpy(tmp, crypt, ctx->u.aes.block_size);
+			os_memcpy(tmp, crypt, AES_BLOCK_SIZE);
 			aes_decrypt(ctx->u.aes.ctx_dec, crypt, plain);
-			for (j = 0; j < ctx->u.aes.block_size; j++)
+			for (j = 0; j < AES_BLOCK_SIZE; j++)
 				plain[j] ^= ctx->u.aes.cbc[j];
-			os_memcpy(ctx->u.aes.cbc, tmp, ctx->u.aes.block_size);
-			plain += ctx->u.aes.block_size;
-			crypt += ctx->u.aes.block_size;
+			os_memcpy(ctx->u.aes.cbc, tmp, AES_BLOCK_SIZE);
+			plain += AES_BLOCK_SIZE;
+			crypt += AES_BLOCK_SIZE;
 		}
 		break;
 	case CRYPTO_CIPHER_ALG_3DES: