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Commit 28db8e3e authored by Mikko Herranen's avatar Mikko Herranen Committed by Herbert Xu
Browse files

[CRYPTO] gcm: New algorithm 



Add GCM/GMAC support to cryptoapi.

GCM (Galois/Counter Mode) is an AEAD mode of operations for any block cipher
with a block size of 16.  The typical example is AES-GCM.

Signed-off-by: default avatarMikko Herranen <mh1@iki.fi>
Reviewed-by: default avatarMika Kukkonen <mika.kukkonen@nsn.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent e3a4ea4f

crypto/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -206,6 +206,15 @@ config CRYPTO_CTR 
	  CTR: Counter mode

	  This block cipher algorithm is required for IPSec.



config CRYPTO_GCM

	tristate "GCM/GMAC support"

	select CRYPTO_CTR

	select CRYPTO_AEAD

	select CRYPTO_GF128MUL

	help

	  Support for Galois/Counter Mode (GCM) and Galois Message

	  Authentication Code (GMAC). Required for IPSec.



config CRYPTO_CRYPTD

	tristate "Software async crypto daemon"

	select CRYPTO_ABLKCIPHER

crypto/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ obj-$(CONFIG_CRYPTO_PCBC) += pcbc.o 
obj-$(CONFIG_CRYPTO_LRW) += lrw.o

obj-$(CONFIG_CRYPTO_XTS) += xts.o

obj-$(CONFIG_CRYPTO_CTR) += ctr.o

obj-$(CONFIG_CRYPTO_GCM) += gcm.o

obj-$(CONFIG_CRYPTO_CRYPTD) += cryptd.o

obj-$(CONFIG_CRYPTO_DES) += des_generic.o

obj-$(CONFIG_CRYPTO_FCRYPT) += fcrypt.o

crypto/gcm.c

0 → 100644
+465 −0
Original line number Diff line number Diff line 
/*

 * GCM: Galois/Counter Mode.

 *

 * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>

 *

 * 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 <crypto/algapi.h>

#include <crypto/gf128mul.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>



#include "scatterwalk.h"



struct gcm_instance_ctx {

	struct crypto_spawn ctr;

};



struct crypto_gcm_ctx {

	struct crypto_ablkcipher *ctr;

	struct gf128mul_4k *gf128;

};



struct crypto_gcm_ghash_ctx {

	u32 bytes;

	u32 flags;

	struct gf128mul_4k *gf128;

	u8 buffer[16];

};



struct crypto_gcm_req_priv_ctx {

	u8 auth_tag[16];

	u8 counter[16];

	struct crypto_gcm_ghash_ctx ghash;

};



static void crypto_gcm_ghash_init(struct crypto_gcm_ghash_ctx *ctx, u32 flags,

				  struct gf128mul_4k *gf128)

{

	ctx->bytes = 0;

	ctx->flags = flags;

	ctx->gf128 = gf128;

	memset(ctx->buffer, 0, 16);

}



static void crypto_gcm_ghash_update(struct crypto_gcm_ghash_ctx *ctx,

				    const u8 *src, unsigned int srclen)

{

	u8 *dst = ctx->buffer;



	if (ctx->bytes) {

		int n = min(srclen, ctx->bytes);

		u8 *pos = dst + (16 - ctx->bytes);



		ctx->bytes -= n;

		srclen -= n;



		while (n--)

			*pos++ ^= *src++;



		if (!ctx->bytes)

			gf128mul_4k_lle((be128 *)dst, ctx->gf128);

	}



	while (srclen >= 16) {

		crypto_xor(dst, src, 16);

		gf128mul_4k_lle((be128 *)dst, ctx->gf128);

		src += 16;

		srclen -= 16;

	}



	if (srclen) {

		ctx->bytes = 16 - srclen;

		while (srclen--)

			*dst++ ^= *src++;

	}

}



static void crypto_gcm_ghash_update_sg(struct crypto_gcm_ghash_ctx *ctx,

				       struct scatterlist *sg, int len)

{

	struct scatter_walk walk;

	u8 *src;

	int n;



	scatterwalk_start(&walk, sg);



	while (len) {

		n = scatterwalk_clamp(&walk, len);



		if (!n) {

			scatterwalk_start(&walk, sg_next(walk.sg));

			n = scatterwalk_clamp(&walk, len);

		}



		src = scatterwalk_map(&walk, 0);



		crypto_gcm_ghash_update(ctx, src, n);

		len -= n;



		scatterwalk_unmap(src, 0);

		scatterwalk_advance(&walk, n);

		scatterwalk_done(&walk, 0, len);

		if (len)

			crypto_yield(ctx->flags);

	}

}



static void crypto_gcm_ghash_flush(struct crypto_gcm_ghash_ctx *ctx)

{

	u8 *dst = ctx->buffer;



	if (ctx->bytes) {

		u8 *tmp = dst + (16 - ctx->bytes);



		while (ctx->bytes--)

			*tmp++ ^= 0;



		gf128mul_4k_lle((be128 *)dst, ctx->gf128);

	}



	ctx->bytes = 0;

}



static void crypto_gcm_ghash_final_xor(struct crypto_gcm_ghash_ctx *ctx,

				       unsigned int authlen,

				       unsigned int cryptlen, u8 *dst)

{

	u8 *buf = ctx->buffer;

	u128 lengths;



	lengths.a = cpu_to_be64(authlen * 8);

	lengths.b = cpu_to_be64(cryptlen * 8);



	crypto_gcm_ghash_flush(ctx);

	crypto_xor(buf, (u8 *)&lengths, 16);

	gf128mul_4k_lle((be128 *)buf, ctx->gf128);

	crypto_xor(dst, buf, 16);

}



static inline void crypto_gcm_set_counter(u8 *counterblock, u32 value)

{

	*((u32 *)&counterblock[12]) = cpu_to_be32(value);

}



static int crypto_gcm_encrypt_counter(struct crypto_aead *aead, u8 *block,

				       u32 value, const u8 *iv)

{

	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);

	struct crypto_ablkcipher *ctr = ctx->ctr;

	struct ablkcipher_request req;

	struct scatterlist sg;

	u8 counterblock[16];



	if (iv == NULL)

		memset(counterblock, 0, 12);

	else

		memcpy(counterblock, iv, 12);



	crypto_gcm_set_counter(counterblock, value);



	sg_init_one(&sg, block, 16);

	ablkcipher_request_set_tfm(&req, ctr);

	ablkcipher_request_set_crypt(&req, &sg, &sg, 16, counterblock);

	ablkcipher_request_set_callback(&req, 0, NULL, NULL);

	memset(block, 0, 16);

	return crypto_ablkcipher_encrypt(&req);

}



static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,

			     unsigned int keylen)

{

	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);

	struct crypto_ablkcipher *ctr = ctx->ctr;

	int alignmask = crypto_ablkcipher_alignmask(ctr);

	u8 alignbuf[16+alignmask];

	u8 *hash = (u8 *)ALIGN((unsigned long)alignbuf, alignmask+1);

	int err = 0;



	crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);

	crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &

				   CRYPTO_TFM_REQ_MASK);



	err = crypto_ablkcipher_setkey(ctr, key, keylen);

	if (err)

		goto out;



	crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &

				       CRYPTO_TFM_RES_MASK);



	err = crypto_gcm_encrypt_counter(aead, hash, -1, NULL);

	if (err)

		goto out;



	if (ctx->gf128 != NULL)

		gf128mul_free_4k(ctx->gf128);



	ctx->gf128 = gf128mul_init_4k_lle((be128 *)hash);



	if (ctx->gf128 == NULL)

		err = -ENOMEM;



 out:

	return err;

}



static int crypto_gcm_init_crypt(struct ablkcipher_request *ablk_req,

				  struct aead_request *req,

				  void (*done)(struct crypto_async_request *,

					       int))

{

	struct crypto_aead *aead = crypto_aead_reqtfm(req);

	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);

	struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);

	u32 flags = req->base.tfm->crt_flags;

	u8 *auth_tag = pctx->auth_tag;

	u8 *counter = pctx->counter;

	struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;

	int err = 0;



	ablkcipher_request_set_tfm(ablk_req, ctx->ctr);

	ablkcipher_request_set_callback(ablk_req, aead_request_flags(req),

					done, req);

	ablkcipher_request_set_crypt(ablk_req, req->src, req->dst,

				     req->cryptlen, counter);



	err = crypto_gcm_encrypt_counter(aead, auth_tag, 0, req->iv);

	if (err)

		goto out;



	memcpy(counter, req->iv, 12);

	crypto_gcm_set_counter(counter, 1);



	crypto_gcm_ghash_init(ghash, flags, ctx->gf128);



	if (req->assoclen) {

		crypto_gcm_ghash_update_sg(ghash, req->assoc, req->assoclen);

		crypto_gcm_ghash_flush(ghash);

	}



 out:

	return err;

}



static void crypto_gcm_encrypt_done(struct crypto_async_request *areq, int err)

{

	struct aead_request *req = areq->data;

	struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);

	u8 *auth_tag = pctx->auth_tag;

	struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;



	crypto_gcm_ghash_update_sg(ghash, req->dst, req->cryptlen);

	crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,

				   auth_tag);



	aead_request_complete(req, err);

}



static int crypto_gcm_encrypt(struct aead_request *req)

{

	struct ablkcipher_request abreq;

	struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);

	u8 *auth_tag = pctx->auth_tag;

	struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;

	int err = 0;



	err = crypto_gcm_init_crypt(&abreq, req, crypto_gcm_encrypt_done);

	if (err)

		return err;



	if (req->cryptlen) {

		err = crypto_ablkcipher_encrypt(&abreq);

		if (err)

			return err;



		crypto_gcm_ghash_update_sg(ghash, req->dst, req->cryptlen);

	}



	crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,

				   auth_tag);



	return err;

}



static void crypto_gcm_decrypt_done(struct crypto_async_request *areq, int err)

{

	aead_request_complete(areq->data, err);

}



static int crypto_gcm_decrypt(struct aead_request *req)

{

	struct ablkcipher_request abreq;

	struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req);

	u8 *auth_tag = pctx->auth_tag;

	struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;

	u8 tag[16];

	int err;



	if (!req->cryptlen)

		return -EINVAL;



	memcpy(tag, auth_tag, 16);

	err = crypto_gcm_init_crypt(&abreq, req, crypto_gcm_decrypt_done);

	if (err)

		return err;



	crypto_gcm_ghash_update_sg(ghash, req->src, req->cryptlen);

	crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,

				   auth_tag);



	if (memcmp(tag, auth_tag, 16))

		return -EINVAL;



	return crypto_ablkcipher_decrypt(&abreq);

}



static int crypto_gcm_init_tfm(struct crypto_tfm *tfm)

{

	struct crypto_instance *inst = (void *)tfm->__crt_alg;

	struct gcm_instance_ctx *ictx = crypto_instance_ctx(inst);

	struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm);

	struct crypto_ablkcipher *ctr;

	unsigned long align;

	int err;



	ctr = crypto_spawn_ablkcipher(&ictx->ctr);

	err = PTR_ERR(ctr);

	if (IS_ERR(ctr))

		return err;



	ctx->ctr = ctr;

	ctx->gf128 = NULL;



	align = max_t(unsigned long, crypto_ablkcipher_alignmask(ctr),

		      __alignof__(u32) - 1);

	align &= ~(crypto_tfm_ctx_alignment() - 1);

	tfm->crt_aead.reqsize = align + sizeof(struct crypto_gcm_req_priv_ctx);



	return 0;

}



static void crypto_gcm_exit_tfm(struct crypto_tfm *tfm)

{

	struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm);



	if (ctx->gf128 != NULL)

		gf128mul_free_4k(ctx->gf128);



	crypto_free_ablkcipher(ctx->ctr);

}



static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)

{

	struct crypto_instance *inst;

	struct crypto_alg *ctr;

	struct crypto_alg *cipher;

	struct gcm_instance_ctx *ctx;

	int err;

	char ctr_name[CRYPTO_MAX_ALG_NAME];



	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD);

	if (err)

		return ERR_PTR(err);



	cipher = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,

			      CRYPTO_ALG_TYPE_MASK);



	inst = ERR_PTR(PTR_ERR(cipher));

	if (IS_ERR(cipher))

		return inst;



	inst = ERR_PTR(ENAMETOOLONG);

	if (snprintf(

		    ctr_name, CRYPTO_MAX_ALG_NAME,

		    "ctr(%s,0,16,4)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME)

		return inst;



	ctr = crypto_alg_mod_lookup(ctr_name, CRYPTO_ALG_TYPE_BLKCIPHER,

				    CRYPTO_ALG_TYPE_MASK);



	if (IS_ERR(ctr))

		return ERR_PTR(PTR_ERR(ctr));



	if (cipher->cra_blocksize != 16)

		goto out_put_ctr;



	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);

	err = -ENOMEM;

	if (!inst)

		goto out_put_ctr;



	err = -ENAMETOOLONG;

	if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,

		     "gcm(%s)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME ||

	    snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,

		     "gcm(%s)", cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)

		goto err_free_inst;





	ctx = crypto_instance_ctx(inst);

	err = crypto_init_spawn(&ctx->ctr, ctr, inst, CRYPTO_ALG_TYPE_MASK);

	if (err)

		goto err_free_inst;



	inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;

	inst->alg.cra_priority = ctr->cra_priority;

	inst->alg.cra_blocksize = 16;

	inst->alg.cra_alignmask = __alignof__(u32) - 1;

	inst->alg.cra_type = &crypto_aead_type;

	inst->alg.cra_aead.ivsize = 12;

	inst->alg.cra_aead.authsize = 16;

	inst->alg.cra_ctxsize = sizeof(struct crypto_gcm_ctx);

	inst->alg.cra_init = crypto_gcm_init_tfm;

	inst->alg.cra_exit = crypto_gcm_exit_tfm;

	inst->alg.cra_aead.setkey = crypto_gcm_setkey;

	inst->alg.cra_aead.encrypt = crypto_gcm_encrypt;

	inst->alg.cra_aead.decrypt = crypto_gcm_decrypt;



out:

	crypto_mod_put(ctr);

	return inst;

err_free_inst:

	kfree(inst);

out_put_ctr:

	inst = ERR_PTR(err);

	goto out;

}



static void crypto_gcm_free(struct crypto_instance *inst)

{

	struct gcm_instance_ctx *ctx = crypto_instance_ctx(inst);



	crypto_drop_spawn(&ctx->ctr);

	kfree(inst);

}



static struct crypto_template crypto_gcm_tmpl = {

	.name = "gcm",

	.alloc = crypto_gcm_alloc,

	.free = crypto_gcm_free,

	.module = THIS_MODULE,

};



static int __init crypto_gcm_module_init(void)

{

	return crypto_register_template(&crypto_gcm_tmpl);

}



static void __exit crypto_gcm_module_exit(void)

{

	crypto_unregister_template(&crypto_gcm_tmpl);

}



module_init(crypto_gcm_module_init);

module_exit(crypto_gcm_module_exit);



MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("Galois/Counter Mode");

MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");

crypto/tcrypt.c

+5 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 * Software Foundation; either version 2 of the License, or (at your option)

 * any later version.

 *

 * 2007-11-13 Added GCM tests

 * 2007-11-13 Added AEAD support

 * 2007-11-06 Added SHA-224 and SHA-224-HMAC tests

 * 2006-12-07 Added SHA384 HMAC and SHA512 HMAC tests
@@ -1208,6 +1209,10 @@ static void do_test(void) 
			    AES_CTR_ENC_TEST_VECTORS);

		test_cipher("ctr(aes,4,8,4)", DECRYPT, aes_ctr_dec_tv_template,

			    AES_CTR_DEC_TEST_VECTORS);

		test_aead("gcm(aes)", ENCRYPT, aes_gcm_enc_tv_template,

			  AES_GCM_ENC_TEST_VECTORS);

		test_aead("gcm(aes)", DECRYPT, aes_gcm_dec_tv_template,

			  AES_GCM_DEC_TEST_VECTORS);



		//CAST5

		test_cipher("ecb(cast5)", ENCRYPT, cast5_enc_tv_template,

crypto/tcrypt.h

+368 −0

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