crypto/xts.c - kernel/msm-5.4 - Gitiles

 /* XTS: as defined in IEEE1619/D16
  *	http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
  *	(sector sizes which are not a multiple of 16 bytes are,
  *	however currently unsupported)
  *
  * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
  *
  * Based on ecb.c
  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * 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 <crypto/internal/skcipher.h>
 #include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>

 #include <crypto/xts.h>
 #include <crypto/b128ops.h>
 #include <crypto/gf128mul.h>

 struct priv {
 	struct crypto_skcipher *child;
 	struct crypto_cipher *tweak;
 };

 struct xts_instance_ctx {
 	struct crypto_skcipher_spawn spawn;
 	char name[CRYPTO_MAX_ALG_NAME];
 };

 struct rctx {
 	le128 t;
 	struct skcipher_request subreq;
 };

 static int setkey(struct crypto_skcipher *parent, const u8 *key,
 		  unsigned int keylen)
 {
 	struct priv *ctx = crypto_skcipher_ctx(parent);
 	struct crypto_skcipher *child;
 	struct crypto_cipher *tweak;
 	int err;

 	err = xts_verify_key(parent, key, keylen);
 	if (err)
 		return err;

 	keylen /= 2;

 	/* we need two cipher instances: one to compute the initial 'tweak'
 	 * by encrypting the IV (usually the 'plain' iv) and the other
 	 * one to encrypt and decrypt the data */

 	/* tweak cipher, uses Key2 i.e. the second half of *key */
 	tweak = ctx->tweak;
 	crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
 	crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
 				       CRYPTO_TFM_REQ_MASK);
 	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
 	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) &
 					  CRYPTO_TFM_RES_MASK);
 	if (err)
 		return err;

 	/* data cipher, uses Key1 i.e. the first half of *key */
 	child = ctx->child;
 	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
 					 CRYPTO_TFM_REQ_MASK);
 	err = crypto_skcipher_setkey(child, key, keylen);
 	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
 					  CRYPTO_TFM_RES_MASK);

 	return err;
 }

 /*
  * We compute the tweak masks twice (both before and after the ECB encryption or
  * decryption) to avoid having to allocate a temporary buffer and/or make
  * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
  * just doing the gf128mul_x_ble() calls again.
  */
 static int xor_tweak(struct skcipher_request *req, bool second_pass)
 {
 	struct rctx *rctx = skcipher_request_ctx(req);
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	const int bs = XTS_BLOCK_SIZE;
 	struct skcipher_walk w;
 	le128 t = rctx->t;
 	int err;

 	if (second_pass) {
 		req = &rctx->subreq;
 		/* set to our TFM to enforce correct alignment: */
 		skcipher_request_set_tfm(req, tfm);
 	}
 	err = skcipher_walk_virt(&w, req, false);

 	while (w.nbytes) {
 		unsigned int avail = w.nbytes;
 		le128 *wsrc;
 		le128 *wdst;

 		wsrc = w.src.virt.addr;
 		wdst = w.dst.virt.addr;

 		do {
 			le128_xor(wdst++, &t, wsrc++);
 			gf128mul_x_ble(&t, &t);
 		} while ((avail -= bs) >= bs);

 		err = skcipher_walk_done(&w, avail);
 	}

 	return err;
 }

 static int xor_tweak_pre(struct skcipher_request *req)
 {
 	return xor_tweak(req, false);
 }

 static int xor_tweak_post(struct skcipher_request *req)
 {
 	return xor_tweak(req, true);
 }

 static void crypt_done(struct crypto_async_request *areq, int err)
 {
 	struct skcipher_request *req = areq->data;

 	if (!err)
 		err = xor_tweak_post(req);

 	skcipher_request_complete(req, err);
 }

 static void init_crypt(struct skcipher_request *req)
 {
 	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	struct rctx *rctx = skcipher_request_ctx(req);
 	struct skcipher_request *subreq = &rctx->subreq;

 	skcipher_request_set_tfm(subreq, ctx->child);
 	skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
 	skcipher_request_set_crypt(subreq, req->dst, req->dst,
 				   req->cryptlen, NULL);

 	/* calculate first value of T */
 	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
 }

 static int encrypt(struct skcipher_request *req)
 {
 	struct rctx *rctx = skcipher_request_ctx(req);
 	struct skcipher_request *subreq = &rctx->subreq;

 	init_crypt(req);
 	return xor_tweak_pre(req) ?:
 		crypto_skcipher_encrypt(subreq) ?:
 		xor_tweak_post(req);
 }

 static int decrypt(struct skcipher_request *req)
 {
 	struct rctx *rctx = skcipher_request_ctx(req);
 	struct skcipher_request *subreq = &rctx->subreq;

 	init_crypt(req);
 	return xor_tweak_pre(req) ?:
 		crypto_skcipher_decrypt(subreq) ?:
 		xor_tweak_post(req);
 }

 static int init_tfm(struct crypto_skcipher *tfm)
 {
 	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
 	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
 	struct priv *ctx = crypto_skcipher_ctx(tfm);
 	struct crypto_skcipher *child;
 	struct crypto_cipher *tweak;

 	child = crypto_spawn_skcipher(&ictx->spawn);
 	if (IS_ERR(child))
 		return PTR_ERR(child);

 	ctx->child = child;

 	tweak = crypto_alloc_cipher(ictx->name, 0, 0);
 	if (IS_ERR(tweak)) {
 		crypto_free_skcipher(ctx->child);
 		return PTR_ERR(tweak);
 	}

 	ctx->tweak = tweak;

 	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
 					 sizeof(struct rctx));

 	return 0;
 }

 static void exit_tfm(struct crypto_skcipher *tfm)
 {
 	struct priv *ctx = crypto_skcipher_ctx(tfm);

 	crypto_free_skcipher(ctx->child);
 	crypto_free_cipher(ctx->tweak);
 }

 static void free(struct skcipher_instance *inst)
 {
 	crypto_drop_skcipher(skcipher_instance_ctx(inst));
 	kfree(inst);
 }

 static int create(struct crypto_template *tmpl, struct rtattr **tb)
 {
 	struct skcipher_instance *inst;
 	struct crypto_attr_type *algt;
 	struct xts_instance_ctx *ctx;
 	struct skcipher_alg *alg;
 	const char *cipher_name;
 	u32 mask;
 	int err;

 	algt = crypto_get_attr_type(tb);
 	if (IS_ERR(algt))
 		return PTR_ERR(algt);

 	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
 		return -EINVAL;

 	cipher_name = crypto_attr_alg_name(tb[1]);
 	if (IS_ERR(cipher_name))
 		return PTR_ERR(cipher_name);

 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 	if (!inst)
 		return -ENOMEM;

 	ctx = skcipher_instance_ctx(inst);

 	crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));

 	mask = crypto_requires_off(algt->type, algt->mask,
 				   CRYPTO_ALG_NEED_FALLBACK |
 				   CRYPTO_ALG_ASYNC);

 	err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
 	if (err == -ENOENT) {
 		err = -ENAMETOOLONG;
 		if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
 			     cipher_name) >= CRYPTO_MAX_ALG_NAME)
 			goto err_free_inst;

 		err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
 	}

 	if (err)
 		goto err_free_inst;

 	alg = crypto_skcipher_spawn_alg(&ctx->spawn);

 	err = -EINVAL;
 	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
 		goto err_drop_spawn;

 	if (crypto_skcipher_alg_ivsize(alg))
 		goto err_drop_spawn;

 	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
 				  &alg->base);
 	if (err)
 		goto err_drop_spawn;

 	err = -EINVAL;
 	cipher_name = alg->base.cra_name;

 	/* Alas we screwed up the naming so we have to mangle the
 	 * cipher name.
 	 */
 	if (!strncmp(cipher_name, "ecb(", 4)) {
 		unsigned len;

 		len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
 		if (len < 2 || len >= sizeof(ctx->name))
 			goto err_drop_spawn;

 		if (ctx->name[len - 1] != ')')
 			goto err_drop_spawn;

 		ctx->name[len - 1] = 0;

 		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 			     "xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
 			err = -ENAMETOOLONG;
 			goto err_drop_spawn;
 		}
 	} else
 		goto err_drop_spawn;

 	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 	inst->alg.base.cra_priority = alg->base.cra_priority;
 	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
 				       (__alignof__(u64) - 1);

 	inst->alg.ivsize = XTS_BLOCK_SIZE;
 	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
 	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;

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

 	inst->alg.init = init_tfm;
 	inst->alg.exit = exit_tfm;

 	inst->alg.setkey = setkey;
 	inst->alg.encrypt = encrypt;
 	inst->alg.decrypt = decrypt;

 	inst->free = free;

 	err = skcipher_register_instance(tmpl, inst);
 	if (err)
 		goto err_drop_spawn;

 out:
 	return err;

 err_drop_spawn:
 	crypto_drop_skcipher(&ctx->spawn);
 err_free_inst:
 	kfree(inst);
 	goto out;
 }

 static struct crypto_template crypto_tmpl = {
 	.name = "xts",
 	.create = create,
 	.module = THIS_MODULE,
 };

 static int __init crypto_module_init(void)
 {
 	return crypto_register_template(&crypto_tmpl);
 }

 static void __exit crypto_module_exit(void)
 {
 	crypto_unregister_template(&crypto_tmpl);
 }

 module_init(crypto_module_init);
 module_exit(crypto_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("XTS block cipher mode");
 MODULE_ALIAS_CRYPTO("xts");
	/* XTS: as defined in IEEE1619/D16
	* http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
	* (sector sizes which are not a multiple of 16 bytes are,
	* however currently unsupported)
	*
	* Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
	*
	* Based on ecb.c
	* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
	*
	* 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 <crypto/internal/skcipher.h>
	#include <crypto/scatterwalk.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/scatterlist.h>
	#include <linux/slab.h>

	#include <crypto/xts.h>
	#include <crypto/b128ops.h>
	#include <crypto/gf128mul.h>

	struct priv {
	struct crypto_skcipher *child;
	struct crypto_cipher *tweak;
	};

	struct xts_instance_ctx {
	struct crypto_skcipher_spawn spawn;
	char name[CRYPTO_MAX_ALG_NAME];
	};

	struct rctx {
	le128 t;
	struct skcipher_request subreq;
	};

	static int setkey(struct crypto_skcipher parent, const u8 key,
	unsigned int keylen)
	{
	struct priv *ctx = crypto_skcipher_ctx(parent);
	struct crypto_skcipher *child;
	struct crypto_cipher *tweak;
	int err;

	err = xts_verify_key(parent, key, keylen);
	if (err)
	return err;

	keylen /= 2;

	/* we need two cipher instances: one to compute the initial 'tweak'
	* by encrypting the IV (usually the 'plain' iv) and the other
	* one to encrypt and decrypt the data */

	/* tweak cipher, uses Key2 i.e. the second half of key /
	tweak = ctx->tweak;
	crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
	CRYPTO_TFM_REQ_MASK);
	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) &
	CRYPTO_TFM_RES_MASK);
	if (err)
	return err;

	/* data cipher, uses Key1 i.e. the first half of key /
	child = ctx->child;
	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
	CRYPTO_TFM_REQ_MASK);
	err = crypto_skcipher_setkey(child, key, keylen);
	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
	CRYPTO_TFM_RES_MASK);

	return err;
	}

	/*
	* We compute the tweak masks twice (both before and after the ECB encryption or
	* decryption) to avoid having to allocate a temporary buffer and/or make
	* mutliple calls to the 'ecb(..)' instance, which usually would be slower than
	* just doing the gf128mul_x_ble() calls again.
	*/
	static int xor_tweak(struct skcipher_request *req, bool second_pass)
	{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	const int bs = XTS_BLOCK_SIZE;
	struct skcipher_walk w;
	le128 t = rctx->t;
	int err;

	if (second_pass) {
	req = &rctx->subreq;
	/* set to our TFM to enforce correct alignment: */
	skcipher_request_set_tfm(req, tfm);
	}
	err = skcipher_walk_virt(&w, req, false);

	while (w.nbytes) {
	unsigned int avail = w.nbytes;
	le128 *wsrc;
	le128 *wdst;

	wsrc = w.src.virt.addr;
	wdst = w.dst.virt.addr;

	do {
	le128_xor(wdst++, &t, wsrc++);
	gf128mul_x_ble(&t, &t);
	} while ((avail -= bs) >= bs);

	err = skcipher_walk_done(&w, avail);
	}

	return err;
	}

	static int xor_tweak_pre(struct skcipher_request *req)
	{
	return xor_tweak(req, false);
	}

	static int xor_tweak_post(struct skcipher_request *req)
	{
	return xor_tweak(req, true);
	}

	static void crypt_done(struct crypto_async_request *areq, int err)
	{
	struct skcipher_request *req = areq->data;

	if (!err)
	err = xor_tweak_post(req);

	skcipher_request_complete(req, err);
	}

	static void init_crypt(struct skcipher_request *req)
	{
	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;

	skcipher_request_set_tfm(subreq, ctx->child);
	skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
	skcipher_request_set_crypt(subreq, req->dst, req->dst,
	req->cryptlen, NULL);

	/* calculate first value of T */
	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
	}

	static int encrypt(struct skcipher_request *req)
	{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;

	init_crypt(req);
	return xor_tweak_pre(req) ?:
	crypto_skcipher_encrypt(subreq) ?:
	xor_tweak_post(req);
	}

	static int decrypt(struct skcipher_request *req)
	{
	struct rctx *rctx = skcipher_request_ctx(req);
	struct skcipher_request *subreq = &rctx->subreq;

	init_crypt(req);
	return xor_tweak_pre(req) ?:
	crypto_skcipher_decrypt(subreq) ?:
	xor_tweak_post(req);
	}

	static int init_tfm(struct crypto_skcipher *tfm)
	{
	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
	struct priv *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *child;
	struct crypto_cipher *tweak;

	child = crypto_spawn_skcipher(&ictx->spawn);
	if (IS_ERR(child))
	return PTR_ERR(child);

	ctx->child = child;

	tweak = crypto_alloc_cipher(ictx->name, 0, 0);
	if (IS_ERR(tweak)) {
	crypto_free_skcipher(ctx->child);
	return PTR_ERR(tweak);
	}

	ctx->tweak = tweak;

	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
	sizeof(struct rctx));

	return 0;
	}

	static void exit_tfm(struct crypto_skcipher *tfm)
	{
	struct priv *ctx = crypto_skcipher_ctx(tfm);

	crypto_free_skcipher(ctx->child);
	crypto_free_cipher(ctx->tweak);
	}

	static void free(struct skcipher_instance *inst)
	{
	crypto_drop_skcipher(skcipher_instance_ctx(inst));
	kfree(inst);
	}

	static int create(struct crypto_template tmpl, struct rtattr *tb)
	{
	struct skcipher_instance *inst;
	struct crypto_attr_type *algt;
	struct xts_instance_ctx *ctx;
	struct skcipher_alg *alg;
	const char *cipher_name;
	u32 mask;
	int err;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
	return PTR_ERR(algt);

	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
	return -EINVAL;

	cipher_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(cipher_name))
	return PTR_ERR(cipher_name);

	inst = kzalloc(sizeof(inst) + sizeof(ctx), GFP_KERNEL);
	if (!inst)
	return -ENOMEM;

	ctx = skcipher_instance_ctx(inst);

	crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));

	mask = crypto_requires_off(algt->type, algt->mask,
	CRYPTO_ALG_NEED_FALLBACK \|
	CRYPTO_ALG_ASYNC);

	err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
	if (err == -ENOENT) {
	err = -ENAMETOOLONG;
	if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
	cipher_name) >= CRYPTO_MAX_ALG_NAME)
	goto err_free_inst;

	err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
	}

	if (err)
	goto err_free_inst;

	alg = crypto_skcipher_spawn_alg(&ctx->spawn);

	err = -EINVAL;
	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
	goto err_drop_spawn;

	if (crypto_skcipher_alg_ivsize(alg))
	goto err_drop_spawn;

	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
	&alg->base);
	if (err)
	goto err_drop_spawn;

	err = -EINVAL;
	cipher_name = alg->base.cra_name;

	/* Alas we screwed up the naming so we have to mangle the
	* cipher name.
	*/
	if (!strncmp(cipher_name, "ecb(", 4)) {
	unsigned len;

	len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
	if (len < 2 \|\| len >= sizeof(ctx->name))
	goto err_drop_spawn;

	if (ctx->name[len - 1] != ')')
	goto err_drop_spawn;

	ctx->name[len - 1] = 0;

	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
	"xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
	err = -ENAMETOOLONG;
	goto err_drop_spawn;
	}
	} else
	goto err_drop_spawn;

	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	inst->alg.base.cra_priority = alg->base.cra_priority;
	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
	inst->alg.base.cra_alignmask = alg->base.cra_alignmask \|
	(__alignof__(u64) - 1);

	inst->alg.ivsize = XTS_BLOCK_SIZE;
	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;

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

	inst->alg.init = init_tfm;
	inst->alg.exit = exit_tfm;

	inst->alg.setkey = setkey;
	inst->alg.encrypt = encrypt;
	inst->alg.decrypt = decrypt;

	inst->free = free;

	err = skcipher_register_instance(tmpl, inst);
	if (err)
	goto err_drop_spawn;

	out:
	return err;

	err_drop_spawn:
	crypto_drop_skcipher(&ctx->spawn);
	err_free_inst:
	kfree(inst);
	goto out;
	}

	static struct crypto_template crypto_tmpl = {
	.name = "xts",
	.create = create,
	.module = THIS_MODULE,
	};

	static int __init crypto_module_init(void)
	{
	return crypto_register_template(&crypto_tmpl);
	}

	static void __exit crypto_module_exit(void)
	{
	crypto_unregister_template(&crypto_tmpl);
	}

	module_init(crypto_module_init);
	module_exit(crypto_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("XTS block cipher mode");
	MODULE_ALIAS_CRYPTO("xts");