crypto/chacha_generic.c - kernel/msm-4.9 - Gitiles

 /*
  * ChaCha and XChaCha stream ciphers, including ChaCha20 (RFC7539)
  *
  * Copyright (C) 2015 Martin Willi
  * Copyright (C) 2018 Google LLC
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  */

 #include <asm/unaligned.h>
 #include <crypto/algapi.h>
 #include <linux/crypto.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <crypto/chacha.h>

 static void chacha_docrypt(u32 *state, u8 *dst, const u8 *src,
 			   unsigned int bytes, int nrounds)
 {
 	/* aligned to potentially speed up crypto_xor() */
 	u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));

 	if (dst != src)
 		memcpy(dst, src, bytes);

 	while (bytes >= CHACHA_BLOCK_SIZE) {
 		chacha_block(state, stream, nrounds);
 		crypto_xor(dst, stream, CHACHA_BLOCK_SIZE);
 		bytes -= CHACHA_BLOCK_SIZE;
 		dst += CHACHA_BLOCK_SIZE;
 	}
 	if (bytes) {
 		chacha_block(state, stream, nrounds);
 		crypto_xor(dst, stream, bytes);
 	}
 }

 static int chacha_stream_xor(struct blkcipher_desc *desc, struct scatterlist *dst,
 			     struct scatterlist *src, unsigned int nbytes,
 			     struct chacha_ctx *ctx, u8 *iv)
 {
 	struct blkcipher_walk walk;
 	u32 state[16];
 	int err;

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

 	crypto_chacha_init(state, ctx, iv);

 	while (walk.nbytes >= CHACHA_BLOCK_SIZE) {
 		chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
 			       rounddown(walk.nbytes, CHACHA_BLOCK_SIZE),
 			       ctx->nrounds);
 		err = blkcipher_walk_done(desc, &walk,
 					  walk.nbytes % CHACHA_BLOCK_SIZE);
 	}

 	if (walk.nbytes) {
 		chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
 			       walk.nbytes, ctx->nrounds);
 		err = blkcipher_walk_done(desc, &walk, 0);
 	}

 	return err;
 }

 void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv)
 {
 	state[0]  = 0x61707865; /* "expa" */
 	state[1]  = 0x3320646e; /* "nd 3" */
 	state[2]  = 0x79622d32; /* "2-by" */
 	state[3]  = 0x6b206574; /* "te k" */
 	state[4]  = ctx->key[0];
 	state[5]  = ctx->key[1];
 	state[6]  = ctx->key[2];
 	state[7]  = ctx->key[3];
 	state[8]  = ctx->key[4];
 	state[9]  = ctx->key[5];
 	state[10] = ctx->key[6];
 	state[11] = ctx->key[7];
 	state[12] = get_unaligned_le32(iv +  0);
 	state[13] = get_unaligned_le32(iv +  4);
 	state[14] = get_unaligned_le32(iv +  8);
 	state[15] = get_unaligned_le32(iv + 12);
 }
 EXPORT_SYMBOL_GPL(crypto_chacha_init);

 static int chacha_setkey(struct crypto_tfm *tfm, const u8 *key,
 			 unsigned int keysize, int nrounds)
 {
 	struct chacha_ctx *ctx = crypto_tfm_ctx(tfm);
 	int i;

 	if (keysize != CHACHA_KEY_SIZE)
 		return -EINVAL;

 	for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
 		ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));

 	ctx->nrounds = nrounds;
 	return 0;
 }

 int crypto_chacha20_setkey(struct crypto_tfm *tfm, const u8 *key,
 			   unsigned int keysize)
 {
 	return chacha_setkey(tfm, key, keysize, 20);
 }
 EXPORT_SYMBOL_GPL(crypto_chacha20_setkey);

 int crypto_chacha12_setkey(struct crypto_tfm *tfm, const u8 *key,
 			   unsigned int keysize)
 {
 	return chacha_setkey(tfm, key, keysize, 12);
 }
 EXPORT_SYMBOL_GPL(crypto_chacha12_setkey);

 int crypto_chacha_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
 			struct scatterlist *src, unsigned int nbytes)
 {
 	struct chacha_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	u8 *iv = desc->info;

 	return chacha_stream_xor(desc, dst, src, nbytes, ctx, iv);
 }
 EXPORT_SYMBOL_GPL(crypto_chacha_crypt);

 int crypto_xchacha_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
 			 struct scatterlist *src, unsigned int nbytes)
 {
 	struct chacha_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 	u8 *iv = desc->info;
 	struct chacha_ctx subctx;
 	u32 state[16];
 	u8 real_iv[16];

 	/* Compute the subkey given the original key and first 128 nonce bits */
 	crypto_chacha_init(state, ctx, iv);
 	hchacha_block(state, subctx.key, ctx->nrounds);
 	subctx.nrounds = ctx->nrounds;

 	/* Build the real IV */
 	memcpy(&real_iv[0], iv + 24, 8); /* stream position */
 	memcpy(&real_iv[8], iv + 16, 8); /* remaining 64 nonce bits */

 	/* Generate the stream and XOR it with the data */
 	return chacha_stream_xor(desc, dst, src, nbytes, &subctx, real_iv);
 }
 EXPORT_SYMBOL_GPL(crypto_xchacha_crypt);

 static struct crypto_alg algs[] = {
 	{
 		.cra_name		= "chacha20",
 		.cra_driver_name	= "chacha20-generic",
 		.cra_priority		= 100,
 		.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
 		.cra_blocksize		= 1,
 		.cra_type		= &crypto_blkcipher_type,
 		.cra_ctxsize		= sizeof(struct chacha_ctx),
 		.cra_alignmask		= sizeof(u32) - 1,
 		.cra_module		= THIS_MODULE,
 		.cra_u			= {
 			.blkcipher = {
 				.min_keysize	= CHACHA_KEY_SIZE,
 				.max_keysize	= CHACHA_KEY_SIZE,
 				.ivsize		= CHACHA_IV_SIZE,
 				.geniv		= "seqiv",
 				.setkey		= crypto_chacha20_setkey,
 				.encrypt	= crypto_chacha_crypt,
 				.decrypt	= crypto_chacha_crypt,
 			},
 		},
 	}, {
 		.cra_name		= "xchacha20",
 		.cra_driver_name	= "xchacha20-generic",
 		.cra_priority		= 100,
 		.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
 		.cra_blocksize		= 1,
 		.cra_type		= &crypto_blkcipher_type,
 		.cra_ctxsize		= sizeof(struct chacha_ctx),
 		.cra_alignmask		= sizeof(u32) - 1,
 		.cra_module		= THIS_MODULE,
 		.cra_u			= {
 			.blkcipher = {
 				.min_keysize	= CHACHA_KEY_SIZE,
 				.max_keysize	= CHACHA_KEY_SIZE,
 				.ivsize		= XCHACHA_IV_SIZE,
 				.geniv		= "seqiv",
 				.setkey		= crypto_chacha20_setkey,
 				.encrypt	= crypto_xchacha_crypt,
 				.decrypt	= crypto_xchacha_crypt,
 			},
 		},
 	}, {
 		.cra_name		= "xchacha12",
 		.cra_driver_name	= "xchacha12-generic",
 		.cra_priority		= 100,
 		.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
 		.cra_blocksize		= 1,
 		.cra_type		= &crypto_blkcipher_type,
 		.cra_ctxsize		= sizeof(struct chacha_ctx),
 		.cra_alignmask		= sizeof(u32) - 1,
 		.cra_module		= THIS_MODULE,
 		.cra_u			= {
 			.blkcipher = {
 				.min_keysize	= CHACHA_KEY_SIZE,
 				.max_keysize	= CHACHA_KEY_SIZE,
 				.ivsize		= XCHACHA_IV_SIZE,
 				.geniv		= "seqiv",
 				.setkey		= crypto_chacha12_setkey,
 				.encrypt	= crypto_xchacha_crypt,
 				.decrypt	= crypto_xchacha_crypt,
 			},
 		},
 	},
 };

 static int __init chacha_generic_mod_init(void)
 {
 	return crypto_register_algs(algs, ARRAY_SIZE(algs));
 }

 static void __exit chacha_generic_mod_fini(void)
 {
 	crypto_unregister_algs(algs, ARRAY_SIZE(algs));
 }

 module_init(chacha_generic_mod_init);
 module_exit(chacha_generic_mod_fini);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (generic)");
 MODULE_ALIAS_CRYPTO("chacha20");
 MODULE_ALIAS_CRYPTO("chacha20-generic");
 MODULE_ALIAS_CRYPTO("xchacha20");
 MODULE_ALIAS_CRYPTO("xchacha20-generic");
 MODULE_ALIAS_CRYPTO("xchacha12");
 MODULE_ALIAS_CRYPTO("xchacha12-generic");
	/*
	* ChaCha and XChaCha stream ciphers, including ChaCha20 (RFC7539)
	*
	* Copyright (C) 2015 Martin Willi
	* Copyright (C) 2018 Google LLC
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*/

	#include <asm/unaligned.h>
	#include <crypto/algapi.h>
	#include <linux/crypto.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <crypto/chacha.h>

	static void chacha_docrypt(u32 state, u8 dst, const u8 *src,
	unsigned int bytes, int nrounds)
	{
	/* aligned to potentially speed up crypto_xor() */
	u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));

	if (dst != src)
	memcpy(dst, src, bytes);

	while (bytes >= CHACHA_BLOCK_SIZE) {
	chacha_block(state, stream, nrounds);
	crypto_xor(dst, stream, CHACHA_BLOCK_SIZE);
	bytes -= CHACHA_BLOCK_SIZE;
	dst += CHACHA_BLOCK_SIZE;
	}
	if (bytes) {
	chacha_block(state, stream, nrounds);
	crypto_xor(dst, stream, bytes);
	}
	}

	static int chacha_stream_xor(struct blkcipher_desc desc, struct scatterlist dst,
	struct scatterlist *src, unsigned int nbytes,
	struct chacha_ctx ctx, u8 iv)
	{
	struct blkcipher_walk walk;
	u32 state[16];
	int err;

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

	crypto_chacha_init(state, ctx, iv);

	while (walk.nbytes >= CHACHA_BLOCK_SIZE) {
	chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
	rounddown(walk.nbytes, CHACHA_BLOCK_SIZE),
	ctx->nrounds);
	err = blkcipher_walk_done(desc, &walk,
	walk.nbytes % CHACHA_BLOCK_SIZE);
	}

	if (walk.nbytes) {
	chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
	walk.nbytes, ctx->nrounds);
	err = blkcipher_walk_done(desc, &walk, 0);
	}

	return err;
	}

	void crypto_chacha_init(u32 state, struct chacha_ctx ctx, u8 *iv)
	{
	state[0] = 0x61707865; /* "expa" */
	state[1] = 0x3320646e; /* "nd 3" */
	state[2] = 0x79622d32; /* "2-by" */
	state[3] = 0x6b206574; /* "te k" */
	state[4] = ctx->key[0];
	state[5] = ctx->key[1];
	state[6] = ctx->key[2];
	state[7] = ctx->key[3];
	state[8] = ctx->key[4];
	state[9] = ctx->key[5];
	state[10] = ctx->key[6];
	state[11] = ctx->key[7];
	state[12] = get_unaligned_le32(iv + 0);
	state[13] = get_unaligned_le32(iv + 4);
	state[14] = get_unaligned_le32(iv + 8);
	state[15] = get_unaligned_le32(iv + 12);
	}
	EXPORT_SYMBOL_GPL(crypto_chacha_init);

	static int chacha_setkey(struct crypto_tfm tfm, const u8 key,
	unsigned int keysize, int nrounds)
	{
	struct chacha_ctx *ctx = crypto_tfm_ctx(tfm);
	int i;

	if (keysize != CHACHA_KEY_SIZE)
	return -EINVAL;

	for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
	ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));

	ctx->nrounds = nrounds;
	return 0;
	}

	int crypto_chacha20_setkey(struct crypto_tfm tfm, const u8 key,
	unsigned int keysize)
	{
	return chacha_setkey(tfm, key, keysize, 20);
	}
	EXPORT_SYMBOL_GPL(crypto_chacha20_setkey);

	int crypto_chacha12_setkey(struct crypto_tfm tfm, const u8 key,
	unsigned int keysize)
	{
	return chacha_setkey(tfm, key, keysize, 12);
	}
	EXPORT_SYMBOL_GPL(crypto_chacha12_setkey);

	int crypto_chacha_crypt(struct blkcipher_desc desc, struct scatterlist dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct chacha_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	u8 *iv = desc->info;

	return chacha_stream_xor(desc, dst, src, nbytes, ctx, iv);
	}
	EXPORT_SYMBOL_GPL(crypto_chacha_crypt);

	int crypto_xchacha_crypt(struct blkcipher_desc desc, struct scatterlist dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct chacha_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	u8 *iv = desc->info;
	struct chacha_ctx subctx;
	u32 state[16];
	u8 real_iv[16];

	/* Compute the subkey given the original key and first 128 nonce bits */
	crypto_chacha_init(state, ctx, iv);
	hchacha_block(state, subctx.key, ctx->nrounds);
	subctx.nrounds = ctx->nrounds;

	/* Build the real IV */
	memcpy(&real_iv[0], iv + 24, 8); /* stream position */
	memcpy(&real_iv[8], iv + 16, 8); /* remaining 64 nonce bits */

	/* Generate the stream and XOR it with the data */
	return chacha_stream_xor(desc, dst, src, nbytes, &subctx, real_iv);
	}
	EXPORT_SYMBOL_GPL(crypto_xchacha_crypt);

	static struct crypto_alg algs[] = {
	{
	.cra_name = "chacha20",
	.cra_driver_name = "chacha20-generic",
	.cra_priority = 100,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize = 1,
	.cra_type = &crypto_blkcipher_type,
	.cra_ctxsize = sizeof(struct chacha_ctx),
	.cra_alignmask = sizeof(u32) - 1,
	.cra_module = THIS_MODULE,
	.cra_u = {
	.blkcipher = {
	.min_keysize = CHACHA_KEY_SIZE,
	.max_keysize = CHACHA_KEY_SIZE,
	.ivsize = CHACHA_IV_SIZE,
	.geniv = "seqiv",
	.setkey = crypto_chacha20_setkey,
	.encrypt = crypto_chacha_crypt,
	.decrypt = crypto_chacha_crypt,
	},
	},
	}, {
	.cra_name = "xchacha20",
	.cra_driver_name = "xchacha20-generic",
	.cra_priority = 100,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize = 1,
	.cra_type = &crypto_blkcipher_type,
	.cra_ctxsize = sizeof(struct chacha_ctx),
	.cra_alignmask = sizeof(u32) - 1,
	.cra_module = THIS_MODULE,
	.cra_u = {
	.blkcipher = {
	.min_keysize = CHACHA_KEY_SIZE,
	.max_keysize = CHACHA_KEY_SIZE,
	.ivsize = XCHACHA_IV_SIZE,
	.geniv = "seqiv",
	.setkey = crypto_chacha20_setkey,
	.encrypt = crypto_xchacha_crypt,
	.decrypt = crypto_xchacha_crypt,
	},
	},
	}, {
	.cra_name = "xchacha12",
	.cra_driver_name = "xchacha12-generic",
	.cra_priority = 100,
	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize = 1,
	.cra_type = &crypto_blkcipher_type,
	.cra_ctxsize = sizeof(struct chacha_ctx),
	.cra_alignmask = sizeof(u32) - 1,
	.cra_module = THIS_MODULE,
	.cra_u = {
	.blkcipher = {
	.min_keysize = CHACHA_KEY_SIZE,
	.max_keysize = CHACHA_KEY_SIZE,
	.ivsize = XCHACHA_IV_SIZE,
	.geniv = "seqiv",
	.setkey = crypto_chacha12_setkey,
	.encrypt = crypto_xchacha_crypt,
	.decrypt = crypto_xchacha_crypt,
	},
	},
	},
	};

	static int __init chacha_generic_mod_init(void)
	{
	return crypto_register_algs(algs, ARRAY_SIZE(algs));
	}

	static void __exit chacha_generic_mod_fini(void)
	{
	crypto_unregister_algs(algs, ARRAY_SIZE(algs));
	}

	module_init(chacha_generic_mod_init);
	module_exit(chacha_generic_mod_fini);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
	MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (generic)");
	MODULE_ALIAS_CRYPTO("chacha20");
	MODULE_ALIAS_CRYPTO("chacha20-generic");
	MODULE_ALIAS_CRYPTO("xchacha20");
	MODULE_ALIAS_CRYPTO("xchacha20-generic");
	MODULE_ALIAS_CRYPTO("xchacha12");
	MODULE_ALIAS_CRYPTO("xchacha12-generic");