arch/arm64/crypto/aes-ce-cipher.c - kernel/lockdown - Git at Google

 /*
  * aes-ce-cipher.c - core AES cipher using ARMv8 Crypto Extensions
  *
  * Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <asm/neon.h>
 #include <crypto/aes.h>
 #include <linux/cpufeature.h>
 #include <linux/crypto.h>
 #include <linux/module.h>

 #include "aes-ce-setkey.h"

 MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 MODULE_LICENSE("GPL v2");

 struct aes_block {
 	u8 b[AES_BLOCK_SIZE];
 };

 static int num_rounds(struct crypto_aes_ctx *ctx)
 {
 	/*
 	 * # of rounds specified by AES:
 	 * 128 bit key		10 rounds
 	 * 192 bit key		12 rounds
 	 * 256 bit key		14 rounds
 	 * => n byte key	=> 6 + (n/4) rounds
 	 */
 	return 6 + ctx->key_length / 4;
 }

 static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
 {
 	struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
 	struct aes_block *out = (struct aes_block *)dst;
 	struct aes_block const *in = (struct aes_block *)src;
 	void *dummy0;
 	int dummy1;

 	kernel_neon_begin_partial(4);

 	__asm__("	ld1	{v0.16b}, %[in]			;"
 		"	ld1	{v1.2d}, [%[key]], #16		;"
 		"	cmp	%w[rounds], #10			;"
 		"	bmi	0f				;"
 		"	bne	3f				;"
 		"	mov	v3.16b, v1.16b			;"
 		"	b	2f				;"
 		"0:	mov	v2.16b, v1.16b			;"
 		"	ld1	{v3.2d}, [%[key]], #16		;"
 		"1:	aese	v0.16b, v2.16b			;"
 		"	aesmc	v0.16b, v0.16b			;"
 		"2:	ld1	{v1.2d}, [%[key]], #16		;"
 		"	aese	v0.16b, v3.16b			;"
 		"	aesmc	v0.16b, v0.16b			;"
 		"3:	ld1	{v2.2d}, [%[key]], #16		;"
 		"	subs	%w[rounds], %w[rounds], #3	;"
 		"	aese	v0.16b, v1.16b			;"
 		"	aesmc	v0.16b, v0.16b			;"
 		"	ld1	{v3.2d}, [%[key]], #16		;"
 		"	bpl	1b				;"
 		"	aese	v0.16b, v2.16b			;"
 		"	eor	v0.16b, v0.16b, v3.16b		;"
 		"	st1	{v0.16b}, %[out]		;"

 	:	[out]		"=Q"(*out),
 		[key]		"=r"(dummy0),
 		[rounds]	"=r"(dummy1)
 	:	[in]		"Q"(*in),
 				"1"(ctx->key_enc),
 				"2"(num_rounds(ctx) - 2)
 	:	"cc");

 	kernel_neon_end();
 }

 static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
 {
 	struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
 	struct aes_block *out = (struct aes_block *)dst;
 	struct aes_block const *in = (struct aes_block *)src;
 	void *dummy0;
 	int dummy1;

 	kernel_neon_begin_partial(4);

 	__asm__("	ld1	{v0.16b}, %[in]			;"
 		"	ld1	{v1.2d}, [%[key]], #16		;"
 		"	cmp	%w[rounds], #10			;"
 		"	bmi	0f				;"
 		"	bne	3f				;"
 		"	mov	v3.16b, v1.16b			;"
 		"	b	2f				;"
 		"0:	mov	v2.16b, v1.16b			;"
 		"	ld1	{v3.2d}, [%[key]], #16		;"
 		"1:	aesd	v0.16b, v2.16b			;"
 		"	aesimc	v0.16b, v0.16b			;"
 		"2:	ld1	{v1.2d}, [%[key]], #16		;"
 		"	aesd	v0.16b, v3.16b			;"
 		"	aesimc	v0.16b, v0.16b			;"
 		"3:	ld1	{v2.2d}, [%[key]], #16		;"
 		"	subs	%w[rounds], %w[rounds], #3	;"
 		"	aesd	v0.16b, v1.16b			;"
 		"	aesimc	v0.16b, v0.16b			;"
 		"	ld1	{v3.2d}, [%[key]], #16		;"
 		"	bpl	1b				;"
 		"	aesd	v0.16b, v2.16b			;"
 		"	eor	v0.16b, v0.16b, v3.16b		;"
 		"	st1	{v0.16b}, %[out]		;"

 	:	[out]		"=Q"(*out),
 		[key]		"=r"(dummy0),
 		[rounds]	"=r"(dummy1)
 	:	[in]		"Q"(*in),
 				"1"(ctx->key_dec),
 				"2"(num_rounds(ctx) - 2)
 	:	"cc");

 	kernel_neon_end();
 }

 /*
  * aes_sub() - use the aese instruction to perform the AES sbox substitution
  *             on each byte in 'input'
  */
 static u32 aes_sub(u32 input)
 {
 	u32 ret;

 	__asm__("dup	v1.4s, %w[in]		;"
 		"movi	v0.16b, #0		;"
 		"aese	v0.16b, v1.16b		;"
 		"umov	%w[out], v0.4s[0]	;"

 	:	[out]	"=r"(ret)
 	:	[in]	"r"(input)
 	:		"v0","v1");

 	return ret;
 }

 int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
 		     unsigned int key_len)
 {
 	/*
 	 * The AES key schedule round constants
 	 */
 	static u8 const rcon[] = {
 		0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
 	};

 	u32 kwords = key_len / sizeof(u32);
 	struct aes_block *key_enc, *key_dec;
 	int i, j;

 	if (key_len != AES_KEYSIZE_128 &&
 	    key_len != AES_KEYSIZE_192 &&
 	    key_len != AES_KEYSIZE_256)
 		return -EINVAL;

 	memcpy(ctx->key_enc, in_key, key_len);
 	ctx->key_length = key_len;

 	kernel_neon_begin_partial(2);
 	for (i = 0; i < sizeof(rcon); i++) {
 		u32 *rki = ctx->key_enc + (i * kwords);
 		u32 *rko = rki + kwords;

 		rko[0] = ror32(aes_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0];
 		rko[1] = rko[0] ^ rki[1];
 		rko[2] = rko[1] ^ rki[2];
 		rko[3] = rko[2] ^ rki[3];

 		if (key_len == AES_KEYSIZE_192) {
 			if (i >= 7)
 				break;
 			rko[4] = rko[3] ^ rki[4];
 			rko[5] = rko[4] ^ rki[5];
 		} else if (key_len == AES_KEYSIZE_256) {
 			if (i >= 6)
 				break;
 			rko[4] = aes_sub(rko[3]) ^ rki[4];
 			rko[5] = rko[4] ^ rki[5];
 			rko[6] = rko[5] ^ rki[6];
 			rko[7] = rko[6] ^ rki[7];
 		}
 	}

 	/*
 	 * Generate the decryption keys for the Equivalent Inverse Cipher.
 	 * This involves reversing the order of the round keys, and applying
 	 * the Inverse Mix Columns transformation on all but the first and
 	 * the last one.
 	 */
 	key_enc = (struct aes_block *)ctx->key_enc;
 	key_dec = (struct aes_block *)ctx->key_dec;
 	j = num_rounds(ctx);

 	key_dec[0] = key_enc[j];
 	for (i = 1, j--; j > 0; i++, j--)
 		__asm__("ld1	{v0.16b}, %[in]		;"
 			"aesimc	v1.16b, v0.16b		;"
 			"st1	{v1.16b}, %[out]	;"

 		:	[out]	"=Q"(key_dec[i])
 		:	[in]	"Q"(key_enc[j])
 		:		"v0","v1");
 	key_dec[i] = key_enc[0];

 	kernel_neon_end();
 	return 0;
 }
 EXPORT_SYMBOL(ce_aes_expandkey);

 int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
 		  unsigned int key_len)
 {
 	struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
 	int ret;

 	ret = ce_aes_expandkey(ctx, in_key, key_len);
 	if (!ret)
 		return 0;

 	tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 	return -EINVAL;
 }
 EXPORT_SYMBOL(ce_aes_setkey);

 static struct crypto_alg aes_alg = {
 	.cra_name		= "aes",
 	.cra_driver_name	= "aes-ce",
 	.cra_priority		= 300,
 	.cra_flags		= CRYPTO_ALG_TYPE_CIPHER,
 	.cra_blocksize		= AES_BLOCK_SIZE,
 	.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
 	.cra_module		= THIS_MODULE,
 	.cra_cipher = {
 		.cia_min_keysize	= AES_MIN_KEY_SIZE,
 		.cia_max_keysize	= AES_MAX_KEY_SIZE,
 		.cia_setkey		= ce_aes_setkey,
 		.cia_encrypt		= aes_cipher_encrypt,
 		.cia_decrypt		= aes_cipher_decrypt
 	}
 };

 static int __init aes_mod_init(void)
 {
 	return crypto_register_alg(&aes_alg);
 }

 static void __exit aes_mod_exit(void)
 {
 	crypto_unregister_alg(&aes_alg);
 }

 module_cpu_feature_match(AES, aes_mod_init);
 module_exit(aes_mod_exit);
	/*
	* aes-ce-cipher.c - core AES cipher using ARMv8 Crypto Extensions
	*
	* Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <asm/neon.h>
	#include <crypto/aes.h>
	#include <linux/cpufeature.h>
	#include <linux/crypto.h>
	#include <linux/module.h>

	#include "aes-ce-setkey.h"

	MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
	MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
	MODULE_LICENSE("GPL v2");

	struct aes_block {
	u8 b[AES_BLOCK_SIZE];
	};

	static int num_rounds(struct crypto_aes_ctx *ctx)
	{
	/*
	* # of rounds specified by AES:
	* 128 bit key 10 rounds
	* 192 bit key 12 rounds
	* 256 bit key 14 rounds
	* => n byte key => 6 + (n/4) rounds
	*/
	return 6 + ctx->key_length / 4;
	}

	static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
	{
	struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
	struct aes_block out = (struct aes_block )dst;
	struct aes_block const in = (struct aes_block )src;
	void *dummy0;
	int dummy1;

	kernel_neon_begin_partial(4);

	__asm__(" ld1 {v0.16b}, %[in] ;"
	" ld1 {v1.2d}, [%[key]], #16 ;"
	" cmp %w[rounds], #10 ;"
	" bmi 0f ;"
	" bne 3f ;"
	" mov v3.16b, v1.16b ;"
	" b 2f ;"
	"0: mov v2.16b, v1.16b ;"
	" ld1 {v3.2d}, [%[key]], #16 ;"
	"1: aese v0.16b, v2.16b ;"
	" aesmc v0.16b, v0.16b ;"
	"2: ld1 {v1.2d}, [%[key]], #16 ;"
	" aese v0.16b, v3.16b ;"
	" aesmc v0.16b, v0.16b ;"
	"3: ld1 {v2.2d}, [%[key]], #16 ;"
	" subs %w[rounds], %w[rounds], #3 ;"
	" aese v0.16b, v1.16b ;"
	" aesmc v0.16b, v0.16b ;"
	" ld1 {v3.2d}, [%[key]], #16 ;"
	" bpl 1b ;"
	" aese v0.16b, v2.16b ;"
	" eor v0.16b, v0.16b, v3.16b ;"
	" st1 {v0.16b}, %[out] ;"

	: [out] "=Q"(*out),
	[key] "=r"(dummy0),
	[rounds] "=r"(dummy1)
	: [in] "Q"(*in),
	"1"(ctx->key_enc),
	"2"(num_rounds(ctx) - 2)
	: "cc");

	kernel_neon_end();
	}

	static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
	{
	struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
	struct aes_block out = (struct aes_block )dst;
	struct aes_block const in = (struct aes_block )src;
	void *dummy0;
	int dummy1;

	kernel_neon_begin_partial(4);

	__asm__(" ld1 {v0.16b}, %[in] ;"
	" ld1 {v1.2d}, [%[key]], #16 ;"
	" cmp %w[rounds], #10 ;"
	" bmi 0f ;"
	" bne 3f ;"
	" mov v3.16b, v1.16b ;"
	" b 2f ;"
	"0: mov v2.16b, v1.16b ;"
	" ld1 {v3.2d}, [%[key]], #16 ;"
	"1: aesd v0.16b, v2.16b ;"
	" aesimc v0.16b, v0.16b ;"
	"2: ld1 {v1.2d}, [%[key]], #16 ;"
	" aesd v0.16b, v3.16b ;"
	" aesimc v0.16b, v0.16b ;"
	"3: ld1 {v2.2d}, [%[key]], #16 ;"
	" subs %w[rounds], %w[rounds], #3 ;"
	" aesd v0.16b, v1.16b ;"
	" aesimc v0.16b, v0.16b ;"
	" ld1 {v3.2d}, [%[key]], #16 ;"
	" bpl 1b ;"
	" aesd v0.16b, v2.16b ;"
	" eor v0.16b, v0.16b, v3.16b ;"
	" st1 {v0.16b}, %[out] ;"

	: [out] "=Q"(*out),
	[key] "=r"(dummy0),
	[rounds] "=r"(dummy1)
	: [in] "Q"(*in),
	"1"(ctx->key_dec),
	"2"(num_rounds(ctx) - 2)
	: "cc");

	kernel_neon_end();
	}

	/*
	* aes_sub() - use the aese instruction to perform the AES sbox substitution
	* on each byte in 'input'
	*/
	static u32 aes_sub(u32 input)
	{
	u32 ret;

	__asm__("dup v1.4s, %w[in] ;"
	"movi v0.16b, #0 ;"
	"aese v0.16b, v1.16b ;"
	"umov %w[out], v0.4s[0] ;"

	: [out] "=r"(ret)
	: [in] "r"(input)
	: "v0","v1");

	return ret;
	}

	int ce_aes_expandkey(struct crypto_aes_ctx ctx, const u8 in_key,
	unsigned int key_len)
	{
	/*
	* The AES key schedule round constants
	*/
	static u8 const rcon[] = {
	0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
	};

	u32 kwords = key_len / sizeof(u32);
	struct aes_block key_enc, key_dec;
	int i, j;

	if (key_len != AES_KEYSIZE_128 &&
	key_len != AES_KEYSIZE_192 &&
	key_len != AES_KEYSIZE_256)
	return -EINVAL;

	memcpy(ctx->key_enc, in_key, key_len);
	ctx->key_length = key_len;

	kernel_neon_begin_partial(2);
	for (i = 0; i < sizeof(rcon); i++) {
	u32 rki = ctx->key_enc + (i kwords);
	u32 *rko = rki + kwords;

	rko[0] = ror32(aes_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0];
	rko[1] = rko[0] ^ rki[1];
	rko[2] = rko[1] ^ rki[2];
	rko[3] = rko[2] ^ rki[3];

	if (key_len == AES_KEYSIZE_192) {
	if (i >= 7)
	break;
	rko[4] = rko[3] ^ rki[4];
	rko[5] = rko[4] ^ rki[5];
	} else if (key_len == AES_KEYSIZE_256) {
	if (i >= 6)
	break;
	rko[4] = aes_sub(rko[3]) ^ rki[4];
	rko[5] = rko[4] ^ rki[5];
	rko[6] = rko[5] ^ rki[6];
	rko[7] = rko[6] ^ rki[7];
	}
	}

	/*
	* Generate the decryption keys for the Equivalent Inverse Cipher.
	* This involves reversing the order of the round keys, and applying
	* the Inverse Mix Columns transformation on all but the first and
	* the last one.
	*/
	key_enc = (struct aes_block *)ctx->key_enc;
	key_dec = (struct aes_block *)ctx->key_dec;
	j = num_rounds(ctx);

	key_dec[0] = key_enc[j];
	for (i = 1, j--; j > 0; i++, j--)
	__asm__("ld1 {v0.16b}, %[in] ;"
	"aesimc v1.16b, v0.16b ;"
	"st1 {v1.16b}, %[out] ;"

	: [out] "=Q"(key_dec[i])
	: [in] "Q"(key_enc[j])
	: "v0","v1");
	key_dec[i] = key_enc[0];

	kernel_neon_end();
	return 0;
	}
	EXPORT_SYMBOL(ce_aes_expandkey);

	int ce_aes_setkey(struct crypto_tfm tfm, const u8 in_key,
	unsigned int key_len)
	{
	struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
	int ret;

	ret = ce_aes_expandkey(ctx, in_key, key_len);
	if (!ret)
	return 0;

	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
	return -EINVAL;
	}
	EXPORT_SYMBOL(ce_aes_setkey);

	static struct crypto_alg aes_alg = {
	.cra_name = "aes",
	.cra_driver_name = "aes-ce",
	.cra_priority = 300,
	.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize = AES_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct crypto_aes_ctx),
	.cra_module = THIS_MODULE,
	.cra_cipher = {
	.cia_min_keysize = AES_MIN_KEY_SIZE,
	.cia_max_keysize = AES_MAX_KEY_SIZE,
	.cia_setkey = ce_aes_setkey,
	.cia_encrypt = aes_cipher_encrypt,
	.cia_decrypt = aes_cipher_decrypt
	}
	};

	static int __init aes_mod_init(void)
	{
	return crypto_register_alg(&aes_alg);
	}

	static void __exit aes_mod_exit(void)
	{
	crypto_unregister_alg(&aes_alg);
	}

	module_cpu_feature_match(AES, aes_mod_init);
	module_exit(aes_mod_exit);