// SPDX-License-Identifier: GPL-2.0-or-later/* * CTR: Counter mode * * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com> */ #include <crypto/algapi.h>#include <crypto/ctr.h>#include <crypto/internal/skcipher.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h> struct crypto_rfc3686_ctx {	struct crypto_skcipher *child;	u8 nonce[CTR_RFC3686_NONCE_SIZE];}; struct crypto_rfc3686_req_ctx {	u8 iv[CTR_RFC3686_BLOCK_SIZE];	struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;}; static void crypto_ctr_crypt_final(struct skcipher_walk *walk,				   struct crypto_cipher *tfm){	unsigned int bsize = crypto_cipher_blocksize(tfm);	unsigned long alignmask = crypto_cipher_alignmask(tfm);	u8 *ctrblk = walk->iv;	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);	u8 *src = walk->src.virt.addr;	u8 *dst = walk->dst.virt.addr;	unsigned int nbytes = walk->nbytes; 	crypto_cipher_encrypt_one(tfm, keystream, ctrblk);	crypto_xor_cpy(dst, keystream, src, nbytes); 	crypto_inc(ctrblk, bsize);} static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,				    struct crypto_cipher *tfm){	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =		   crypto_cipher_alg(tfm)->cia_encrypt;	unsigned int bsize = crypto_cipher_blocksize(tfm);	u8 *ctrblk = walk->iv;	u8 *src = walk->src.virt.addr;	u8 *dst = walk->dst.virt.addr;	unsigned int nbytes = walk->nbytes; 	do {		/* create keystream */		fn(crypto_cipher_tfm(tfm), dst, ctrblk);		crypto_xor(dst, src, bsize); 		/* increment counter in counterblock */		crypto_inc(ctrblk, bsize); 		src += bsize;		dst += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,				    struct crypto_cipher *tfm){	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =		   crypto_cipher_alg(tfm)->cia_encrypt;	unsigned int bsize = crypto_cipher_blocksize(tfm);	unsigned long alignmask = crypto_cipher_alignmask(tfm);	unsigned int nbytes = walk->nbytes;	u8 *ctrblk = walk->iv;	u8 *src = walk->src.virt.addr;	u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];	u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1); 	do {		/* create keystream */		fn(crypto_cipher_tfm(tfm), keystream, ctrblk);		crypto_xor(src, keystream, bsize); 		/* increment counter in counterblock */		crypto_inc(ctrblk, bsize); 		src += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static int crypto_ctr_crypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);	const unsigned int bsize = crypto_cipher_blocksize(cipher);	struct skcipher_walk walk;	unsigned int nbytes;	int err; 	err = skcipher_walk_virt(&walk, req, false); 	while (walk.nbytes >= bsize) {		if (walk.src.virt.addr == walk.dst.virt.addr)			nbytes = crypto_ctr_crypt_inplace(&walk, cipher);		else			nbytes = crypto_ctr_crypt_segment(&walk, cipher); 		err = skcipher_walk_done(&walk, nbytes);	} 	if (walk.nbytes) {		crypto_ctr_crypt_final(&walk, cipher);		err = skcipher_walk_done(&walk, 0);	} 	return err;} static int crypto_ctr_create(struct crypto_template *tmpl, struct rtattr **tb){	struct skcipher_instance *inst;	struct crypto_alg *alg;	int err; 	inst = skcipher_alloc_instance_simple(tmpl, tb);	if (IS_ERR(inst))		return PTR_ERR(inst); 	alg = skcipher_ialg_simple(inst); 	/* Block size must be >= 4 bytes. */	err = -EINVAL;	if (alg->cra_blocksize < 4)		goto out_free_inst; 	/* If this is false we'd fail the alignment of crypto_inc. */	if (alg->cra_blocksize % 4)		goto out_free_inst; 	/* CTR mode is a stream cipher. */	inst->alg.base.cra_blocksize = 1; 	/*	 * To simplify the implementation, configure the skcipher walk to only	 * give a partial block at the very end, never earlier.	 */	inst->alg.chunksize = alg->cra_blocksize; 	inst->alg.encrypt = crypto_ctr_crypt;	inst->alg.decrypt = crypto_ctr_crypt; 	err = skcipher_register_instance(tmpl, inst);	if (err) {out_free_inst:		inst->free(inst);	} 	return err;} static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,				 const u8 *key, unsigned int keylen){	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);	struct crypto_skcipher *child = ctx->child; 	/* the nonce is stored in bytes at end of key */	if (keylen < CTR_RFC3686_NONCE_SIZE)		return -EINVAL; 	memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),	       CTR_RFC3686_NONCE_SIZE); 	keylen -= CTR_RFC3686_NONCE_SIZE; 	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &					 CRYPTO_TFM_REQ_MASK);	return crypto_skcipher_setkey(child, key, keylen);} static int crypto_rfc3686_crypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);	struct crypto_skcipher *child = ctx->child;	unsigned long align = crypto_skcipher_alignmask(tfm);	struct crypto_rfc3686_req_ctx *rctx =		(void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);	struct skcipher_request *subreq = &rctx->subreq;	u8 *iv = rctx->iv; 	/* set up counter block */	memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);	memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE); 	/* initialize counter portion of counter block */	*(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =		cpu_to_be32(1); 	skcipher_request_set_tfm(subreq, child);	skcipher_request_set_callback(subreq, req->base.flags,				      req->base.complete, req->base.data);	skcipher_request_set_crypt(subreq, req->src, req->dst,				   req->cryptlen, iv); 	return crypto_skcipher_encrypt(subreq);} static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm){	struct skcipher_instance *inst = skcipher_alg_instance(tfm);	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);	struct crypto_skcipher *cipher;	unsigned long align;	unsigned int reqsize; 	cipher = crypto_spawn_skcipher(spawn);	if (IS_ERR(cipher))		return PTR_ERR(cipher); 	ctx->child = cipher; 	align = crypto_skcipher_alignmask(tfm);	align &= ~(crypto_tfm_ctx_alignment() - 1);	reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +		  crypto_skcipher_reqsize(cipher);	crypto_skcipher_set_reqsize(tfm, reqsize); 	return 0;} static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm){	struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm); 	crypto_free_skcipher(ctx->child);} static void crypto_rfc3686_free(struct skcipher_instance *inst){	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst); 	crypto_drop_skcipher(spawn);	kfree(inst);} static int crypto_rfc3686_create(struct crypto_template *tmpl,				 struct rtattr **tb){	struct skcipher_instance *inst;	struct skcipher_alg *alg;	struct crypto_skcipher_spawn *spawn;	u32 mask;	int err; 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);	if (err)		return err; 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);	if (!inst)		return -ENOMEM; 	spawn = skcipher_instance_ctx(inst); 	err = crypto_grab_skcipher(spawn, skcipher_crypto_instance(inst),				   crypto_attr_alg_name(tb[1]), 0, mask);	if (err)		goto err_free_inst; 	alg = crypto_spawn_skcipher_alg(spawn); 	/* We only support 16-byte blocks. */	err = -EINVAL;	if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)		goto err_free_inst; 	/* Not a stream cipher? */	if (alg->base.cra_blocksize != 1)		goto err_free_inst; 	err = -ENAMETOOLONG;	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,		     "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)		goto err_free_inst;	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,		     "rfc3686(%s)", alg->base.cra_driver_name) >=	    CRYPTO_MAX_ALG_NAME)		goto err_free_inst; 	inst->alg.base.cra_priority = alg->base.cra_priority;	inst->alg.base.cra_blocksize = 1;	inst->alg.base.cra_alignmask = alg->base.cra_alignmask; 	inst->alg.ivsize = CTR_RFC3686_IV_SIZE;	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +				CTR_RFC3686_NONCE_SIZE;	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +				CTR_RFC3686_NONCE_SIZE; 	inst->alg.setkey = crypto_rfc3686_setkey;	inst->alg.encrypt = crypto_rfc3686_crypt;	inst->alg.decrypt = crypto_rfc3686_crypt; 	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx); 	inst->alg.init = crypto_rfc3686_init_tfm;	inst->alg.exit = crypto_rfc3686_exit_tfm; 	inst->free = crypto_rfc3686_free; 	err = skcipher_register_instance(tmpl, inst);	if (err) {err_free_inst:		crypto_rfc3686_free(inst);	}	return err;} static struct crypto_template crypto_ctr_tmpls[] = {	{		.name = "ctr",		.create = crypto_ctr_create,		.module = THIS_MODULE,	}, {		.name = "rfc3686",		.create = crypto_rfc3686_create,		.module = THIS_MODULE,	},}; static int __init crypto_ctr_module_init(void){	return crypto_register_templates(crypto_ctr_tmpls,					 ARRAY_SIZE(crypto_ctr_tmpls));} static void __exit crypto_ctr_module_exit(void){	crypto_unregister_templates(crypto_ctr_tmpls,				    ARRAY_SIZE(crypto_ctr_tmpls));} subsys_initcall(crypto_ctr_module_init);module_exit(crypto_ctr_module_exit); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("CTR block cipher mode of operation");MODULE_ALIAS_CRYPTO("rfc3686");MODULE_ALIAS_CRYPTO("ctr");