padlock-aes.c

linux 内核源代码

	ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize;

	/* Don't generate extended keys if the hardware can do it. */
	if (aes_hw_extkey_available(key_len))
		return 0;

	ctx->D = ctx->d_data;
	ctx->cword.encrypt.keygen = 1;
	ctx->cword.decrypt.keygen = 1;

	switch (key_len) {
	case 16:
		t = E_KEY[3];
		for (i = 0; i < 10; ++i)
			loop4 (i);
		break;

	case 24:
		E_KEY[4] = le32_to_cpu(key[4]);
		t = E_KEY[5] = le32_to_cpu(key[5]);
		for (i = 0; i < 8; ++i)
			loop6 (i);
		break;

	case 32:
		E_KEY[4] = le32_to_cpu(key[4]);
		E_KEY[5] = le32_to_cpu(key[5]);
		E_KEY[6] = le32_to_cpu(key[6]);
		t = E_KEY[7] = le32_to_cpu(key[7]);
		for (i = 0; i < 7; ++i)
			loop8 (i);
		break;
	}

	D_KEY[0] = E_KEY[0];
	D_KEY[1] = E_KEY[1];
	D_KEY[2] = E_KEY[2];
	D_KEY[3] = E_KEY[3];

	for (i = 4; i < key_len + 24; ++i) {
		imix_col (D_KEY[i], E_KEY[i]);
	}

	/* PadLock needs a different format of the decryption key. */
	rounds = 10 + (key_len - 16) / 4;

	for (i = 0; i < rounds; i++) {
		P[((i + 1) * 4) + 0] = D_KEY[((rounds - i - 1) * 4) + 0];
		P[((i + 1) * 4) + 1] = D_KEY[((rounds - i - 1) * 4) + 1];
		P[((i + 1) * 4) + 2] = D_KEY[((rounds - i - 1) * 4) + 2];
		P[((i + 1) * 4) + 3] = D_KEY[((rounds - i - 1) * 4) + 3];
	}

	P[0] = E_KEY[(rounds * 4) + 0];
	P[1] = E_KEY[(rounds * 4) + 1];
	P[2] = E_KEY[(rounds * 4) + 2];
	P[3] = E_KEY[(rounds * 4) + 3];

	memcpy(D_KEY, P, AES_EXTENDED_KEY_SIZE_B);

	return 0;
}

/* ====== Encryption/decryption routines ====== */

/* These are the real call to PadLock. */
static inline void padlock_xcrypt(const u8 *input, u8 *output, void *key,
				  void *control_word)
{
	asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"	/* rep xcryptecb */
		      : "+S"(input), "+D"(output)
		      : "d"(control_word), "b"(key), "c"(1));
}

static void aes_crypt_copy(const u8 *in, u8 *out, u32 *key, struct cword *cword)
{
	u8 buf[AES_BLOCK_SIZE * 2 + PADLOCK_ALIGNMENT - 1];
	u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);

	memcpy(tmp, in, AES_BLOCK_SIZE);
	padlock_xcrypt(tmp, out, key, cword);
}

static inline void aes_crypt(const u8 *in, u8 *out, u32 *key,
			     struct cword *cword)
{
	asm volatile ("pushfl; popfl");

	/* padlock_xcrypt requires at least two blocks of data. */
	if (unlikely(!(((unsigned long)in ^ (PAGE_SIZE - AES_BLOCK_SIZE)) &
		       (PAGE_SIZE - 1)))) {
		aes_crypt_copy(in, out, key, cword);
		return;
	}

	padlock_xcrypt(in, out, key, cword);
}

static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key,
				      void *control_word, u32 count)
{
	if (count == 1) {
		aes_crypt(input, output, key, control_word);
		return;
	}

	asm volatile ("pushfl; popfl");		/* enforce key reload. */
	asm volatile ("test $1, %%cl;"
		      "je 1f;"
		      "lea -1(%%ecx), %%eax;"
		      "mov $1, %%ecx;"
		      ".byte 0xf3,0x0f,0xa7,0xc8;"	/* rep xcryptecb */
		      "mov %%eax, %%ecx;"
		      "1:"
		      ".byte 0xf3,0x0f,0xa7,0xc8"	/* rep xcryptecb */
		      : "+S"(input), "+D"(output)
		      : "d"(control_word), "b"(key), "c"(count)
		      : "ax");
}

static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
				     u8 *iv, void *control_word, u32 count)
{
	/* Enforce key reload. */
	asm volatile ("pushfl; popfl");
	/* rep xcryptcbc */
	asm volatile (".byte 0xf3,0x0f,0xa7,0xd0"
		      : "+S" (input), "+D" (output), "+a" (iv)
		      : "d" (control_word), "b" (key), "c" (count));
	return iv;
}

static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct aes_ctx *ctx = aes_ctx(tfm);
	aes_crypt(in, out, ctx->E, &ctx->cword.encrypt);
}

static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct aes_ctx *ctx = aes_ctx(tfm);
	aes_crypt(in, out, ctx->D, &ctx->cword.decrypt);
}

static struct crypto_alg aes_alg = {
	.cra_name		=	"aes",
	.cra_driver_name	=	"aes-padlock",
	.cra_priority		=	PADLOCK_CRA_PRIORITY,
	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize		=	AES_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct aes_ctx),
	.cra_alignmask		=	PADLOCK_ALIGNMENT - 1,
	.cra_module		=	THIS_MODULE,
	.cra_list		=	LIST_HEAD_INIT(aes_alg.cra_list),
	.cra_u			=	{
		.cipher = {
			.cia_min_keysize	=	AES_MIN_KEY_SIZE,
			.cia_max_keysize	=	AES_MAX_KEY_SIZE,
			.cia_setkey	   	= 	aes_set_key,
			.cia_encrypt	 	=	aes_encrypt,
			.cia_decrypt	  	=	aes_decrypt,
		}
	}
};

static int ecb_aes_encrypt(struct blkcipher_desc *desc,
			   struct scatterlist *dst, struct scatterlist *src,
			   unsigned int nbytes)
{
	struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
				   ctx->E, &ctx->cword.encrypt,
				   nbytes / AES_BLOCK_SIZE);
		nbytes &= AES_BLOCK_SIZE - 1;
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static int ecb_aes_decrypt(struct blkcipher_desc *desc,
			   struct scatterlist *dst, struct scatterlist *src,
			   unsigned int nbytes)
{
	struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
				   ctx->D, &ctx->cword.decrypt,
				   nbytes / AES_BLOCK_SIZE);
		nbytes &= AES_BLOCK_SIZE - 1;
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static struct crypto_alg ecb_aes_alg = {
	.cra_name		=	"ecb(aes)",
	.cra_driver_name	=	"ecb-aes-padlock",
	.cra_priority		=	PADLOCK_COMPOSITE_PRIORITY,
	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		=	AES_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct aes_ctx),
	.cra_alignmask		=	PADLOCK_ALIGNMENT - 1,
	.cra_type		=	&crypto_blkcipher_type,
	.cra_module		=	THIS_MODULE,
	.cra_list		=	LIST_HEAD_INIT(ecb_aes_alg.cra_list),
	.cra_u			=	{
		.blkcipher = {
			.min_keysize		=	AES_MIN_KEY_SIZE,
			.max_keysize		=	AES_MAX_KEY_SIZE,
			.setkey	   		= 	aes_set_key,
			.encrypt		=	ecb_aes_encrypt,
			.decrypt		=	ecb_aes_decrypt,
		}
	}
};

static int cbc_aes_encrypt(struct blkcipher_desc *desc,
			   struct scatterlist *dst, struct scatterlist *src,
			   unsigned int nbytes)
{
	struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		u8 *iv = padlock_xcrypt_cbc(walk.src.virt.addr,
					    walk.dst.virt.addr, ctx->E,
					    walk.iv, &ctx->cword.encrypt,
					    nbytes / AES_BLOCK_SIZE);
		memcpy(walk.iv, iv, AES_BLOCK_SIZE);
		nbytes &= AES_BLOCK_SIZE - 1;
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static int cbc_aes_decrypt(struct blkcipher_desc *desc,
			   struct scatterlist *dst, struct scatterlist *src,
			   unsigned int nbytes)
{
	struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		padlock_xcrypt_cbc(walk.src.virt.addr, walk.dst.virt.addr,
				   ctx->D, walk.iv, &ctx->cword.decrypt,
				   nbytes / AES_BLOCK_SIZE);
		nbytes &= AES_BLOCK_SIZE - 1;
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static struct crypto_alg cbc_aes_alg = {
	.cra_name		=	"cbc(aes)",
	.cra_driver_name	=	"cbc-aes-padlock",
	.cra_priority		=	PADLOCK_COMPOSITE_PRIORITY,
	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		=	AES_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct aes_ctx),
	.cra_alignmask		=	PADLOCK_ALIGNMENT - 1,
	.cra_type		=	&crypto_blkcipher_type,
	.cra_module		=	THIS_MODULE,
	.cra_list		=	LIST_HEAD_INIT(cbc_aes_alg.cra_list),
	.cra_u			=	{
		.blkcipher = {
			.min_keysize		=	AES_MIN_KEY_SIZE,
			.max_keysize		=	AES_MAX_KEY_SIZE,
			.ivsize			=	AES_BLOCK_SIZE,
			.setkey	   		= 	aes_set_key,
			.encrypt		=	cbc_aes_encrypt,
			.decrypt		=	cbc_aes_decrypt,
		}
	}
};

static int __init padlock_init(void)
{
	int ret;

	if (!cpu_has_xcrypt) {
		printk(KERN_ERR PFX "VIA PadLock not detected.\n");
		return -ENODEV;
	}

	if (!cpu_has_xcrypt_enabled) {
		printk(KERN_ERR PFX "VIA PadLock detected, but not enabled. Hmm, strange...\n");
		return -ENODEV;
	}

	gen_tabs();
	if ((ret = crypto_register_alg(&aes_alg)))
		goto aes_err;

	if ((ret = crypto_register_alg(&ecb_aes_alg)))
		goto ecb_aes_err;

	if ((ret = crypto_register_alg(&cbc_aes_alg)))
		goto cbc_aes_err;

	printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n");

out:
	return ret;

cbc_aes_err:
	crypto_unregister_alg(&ecb_aes_alg);
ecb_aes_err:
	crypto_unregister_alg(&aes_alg);
aes_err:
	printk(KERN_ERR PFX "VIA PadLock AES initialization failed.\n");
	goto out;
}

static void __exit padlock_fini(void)
{
	crypto_unregister_alg(&cbc_aes_alg);
	crypto_unregister_alg(&ecb_aes_alg);
	crypto_unregister_alg(&aes_alg);
}

module_init(padlock_init);
module_exit(padlock_fini);

MODULE_DESCRIPTION("VIA PadLock AES algorithm support");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michal Ludvig");

MODULE_ALIAS("aes");