crypto/aes.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Crypto API support for AES block cipher
 *
 * Copyright 2026 Google LLC
 */

#include <crypto/aes-cbc-macs.h>
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <crypto/internal/hash.h>
#include <linux/module.h>

static_assert(__alignof__(struct aes_key) <= CRYPTO_MINALIGN);

static int crypto_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
			     unsigned int key_len)
{
	struct aes_key *key = crypto_tfm_ctx(tfm);

	return aes_preparekey(key, in_key, key_len);
}

static void crypto_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	const struct aes_key *key = crypto_tfm_ctx(tfm);

	aes_encrypt(key, out, in);
}

static void crypto_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	const struct aes_key *key = crypto_tfm_ctx(tfm);

	aes_decrypt(key, out, in);
}

static_assert(__alignof__(struct aes_cmac_key) <= CRYPTO_MINALIGN);
#define AES_CMAC_KEY(tfm) ((struct aes_cmac_key *)crypto_shash_ctx(tfm))
#define AES_CMAC_CTX(desc) ((struct aes_cmac_ctx *)shash_desc_ctx(desc))

static int __maybe_unused crypto_aes_cmac_setkey(struct crypto_shash *tfm,
						 const u8 *in_key,
						 unsigned int key_len)
{
	return aes_cmac_preparekey(AES_CMAC_KEY(tfm), in_key, key_len);
}

static int __maybe_unused crypto_aes_xcbc_setkey(struct crypto_shash *tfm,
						 const u8 *in_key,
						 unsigned int key_len)
{
	if (key_len != AES_KEYSIZE_128)
		return -EINVAL;
	aes_xcbcmac_preparekey(AES_CMAC_KEY(tfm), in_key);
	return 0;
}

static int __maybe_unused crypto_aes_cmac_init(struct shash_desc *desc)
{
	aes_cmac_init(AES_CMAC_CTX(desc), AES_CMAC_KEY(desc->tfm));
	return 0;
}

static int __maybe_unused crypto_aes_cmac_update(struct shash_desc *desc,
						 const u8 *data,
						 unsigned int len)
{
	aes_cmac_update(AES_CMAC_CTX(desc), data, len);
	return 0;
}

static int __maybe_unused crypto_aes_cmac_final(struct shash_desc *desc,
						u8 *out)
{
	aes_cmac_final(AES_CMAC_CTX(desc), out);
	return 0;
}

static int __maybe_unused crypto_aes_cmac_digest(struct shash_desc *desc,
						 const u8 *data,
						 unsigned int len, u8 *out)
{
	aes_cmac(AES_CMAC_KEY(desc->tfm), data, len, out);
	return 0;
}

static_assert(__alignof__(struct aes_enckey) <= CRYPTO_MINALIGN);
#define AES_CBCMAC_KEY(tfm) ((struct aes_enckey *)crypto_shash_ctx(tfm))
#define AES_CBCMAC_CTX(desc) ((struct aes_cbcmac_ctx *)shash_desc_ctx(desc))

static int __maybe_unused crypto_aes_cbcmac_setkey(struct crypto_shash *tfm,
						   const u8 *in_key,
						   unsigned int key_len)
{
	return aes_prepareenckey(AES_CBCMAC_KEY(tfm), in_key, key_len);
}

static int __maybe_unused crypto_aes_cbcmac_init(struct shash_desc *desc)
{
	aes_cbcmac_init(AES_CBCMAC_CTX(desc), AES_CBCMAC_KEY(desc->tfm));
	return 0;
}

static int __maybe_unused crypto_aes_cbcmac_update(struct shash_desc *desc,
						   const u8 *data,
						   unsigned int len)
{
	aes_cbcmac_update(AES_CBCMAC_CTX(desc), data, len);
	return 0;
}

static int __maybe_unused crypto_aes_cbcmac_final(struct shash_desc *desc,
						  u8 *out)
{
	aes_cbcmac_final(AES_CBCMAC_CTX(desc), out);
	return 0;
}

static int __maybe_unused crypto_aes_cbcmac_digest(struct shash_desc *desc,
						   const u8 *data,
						   unsigned int len, u8 *out)
{
	aes_cbcmac_init(AES_CBCMAC_CTX(desc), AES_CBCMAC_KEY(desc->tfm));
	aes_cbcmac_update(AES_CBCMAC_CTX(desc), data, len);
	aes_cbcmac_final(AES_CBCMAC_CTX(desc), out);
	return 0;
}

static struct crypto_alg alg = {
	.cra_name = "aes",
	.cra_driver_name = "aes-lib",
	.cra_priority = 100,
	.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize = AES_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct aes_key),
	.cra_module = THIS_MODULE,
	.cra_u = { .cipher = { .cia_min_keysize = AES_MIN_KEY_SIZE,
			       .cia_max_keysize = AES_MAX_KEY_SIZE,
			       .cia_setkey = crypto_aes_setkey,
			       .cia_encrypt = crypto_aes_encrypt,
			       .cia_decrypt = crypto_aes_decrypt } }
};

static struct shash_alg mac_algs[] = {
#if IS_ENABLED(CONFIG_CRYPTO_CMAC)
	{
		.base.cra_name = "cmac(aes)",
		.base.cra_driver_name = "cmac-aes-lib",
		.base.cra_priority = 300,
		.base.cra_blocksize = AES_BLOCK_SIZE,
		.base.cra_ctxsize = sizeof(struct aes_cmac_key),
		.base.cra_module = THIS_MODULE,
		.digestsize = AES_BLOCK_SIZE,
		.setkey = crypto_aes_cmac_setkey,
		.init = crypto_aes_cmac_init,
		.update = crypto_aes_cmac_update,
		.final = crypto_aes_cmac_final,
		.digest = crypto_aes_cmac_digest,
		.descsize = sizeof(struct aes_cmac_ctx),
	},
#endif
#if IS_ENABLED(CONFIG_CRYPTO_XCBC)
	{
		/*
		 * Note that the only difference between xcbc(aes) and cmac(aes)
		 * is the preparekey function.
		 */
		.base.cra_name = "xcbc(aes)",
		.base.cra_driver_name = "xcbc-aes-lib",
		.base.cra_priority = 300,
		.base.cra_blocksize = AES_BLOCK_SIZE,
		.base.cra_ctxsize = sizeof(struct aes_cmac_key),
		.base.cra_module = THIS_MODULE,
		.digestsize = AES_BLOCK_SIZE,
		.setkey = crypto_aes_xcbc_setkey,
		.init = crypto_aes_cmac_init,
		.update = crypto_aes_cmac_update,
		.final = crypto_aes_cmac_final,
		.digest = crypto_aes_cmac_digest,
		.descsize = sizeof(struct aes_cmac_ctx),
	},
#endif
#if IS_ENABLED(CONFIG_CRYPTO_CCM)
	{
		.base.cra_name = "cbcmac(aes)",
		.base.cra_driver_name = "cbcmac-aes-lib",
		.base.cra_priority = 300,
		.base.cra_blocksize = AES_BLOCK_SIZE,
		.base.cra_ctxsize = sizeof(struct aes_enckey),
		.base.cra_module = THIS_MODULE,
		.digestsize = AES_BLOCK_SIZE,
		.setkey = crypto_aes_cbcmac_setkey,
		.init = crypto_aes_cbcmac_init,
		.update = crypto_aes_cbcmac_update,
		.final = crypto_aes_cbcmac_final,
		.digest = crypto_aes_cbcmac_digest,
		.descsize = sizeof(struct aes_cbcmac_ctx),
	},
#endif
};

static int __init crypto_aes_mod_init(void)
{
	int err = crypto_register_alg(&alg);

	if (err)
		return err;

	if (ARRAY_SIZE(mac_algs) > 0) {
		err = crypto_register_shashes(mac_algs, ARRAY_SIZE(mac_algs));
		if (err)
			goto err_unregister_alg;
	} /* Else, CONFIG_CRYPTO_HASH might not be enabled. */
	return 0;

err_unregister_alg:
	crypto_unregister_alg(&alg);
	return err;
}
module_init(crypto_aes_mod_init);

static void __exit crypto_aes_mod_exit(void)
{
	if (ARRAY_SIZE(mac_algs) > 0)
		crypto_unregister_shashes(mac_algs, ARRAY_SIZE(mac_algs));
	crypto_unregister_alg(&alg);
}
module_exit(crypto_aes_mod_exit);

MODULE_DESCRIPTION("Crypto API support for AES block cipher");
MODULE_IMPORT_NS("CRYPTO_INTERNAL");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("aes");
MODULE_ALIAS_CRYPTO("aes-lib");
#if IS_ENABLED(CONFIG_CRYPTO_CMAC)
MODULE_ALIAS_CRYPTO("cmac(aes)");
MODULE_ALIAS_CRYPTO("cmac-aes-lib");
#endif
#if IS_ENABLED(CONFIG_CRYPTO_XCBC)
MODULE_ALIAS_CRYPTO("xcbc(aes)");
MODULE_ALIAS_CRYPTO("xcbc-aes-lib");
#endif
#if IS_ENABLED(CONFIG_CRYPTO_CCM)
MODULE_ALIAS_CRYPTO("cbcmac(aes)");
MODULE_ALIAS_CRYPTO("cbcmac-aes-lib");
#endif