// SPDX-License-Identifier: GPL-2.0-or-later/* * seqiv: Sequence Number IV Generator * * This generator generates an IV based on a sequence number by xoring it * with a salt.  This algorithm is mainly useful for CTR and similar modes. * * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> */ #include <crypto/internal/geniv.h>#include <crypto/scatterwalk.h>#include <crypto/skcipher.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/string.h> static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err){	struct aead_request *subreq = aead_request_ctx(req);	struct crypto_aead *geniv; 	if (err == -EINPROGRESS)		return; 	if (err)		goto out; 	geniv = crypto_aead_reqtfm(req);	memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv)); out:	kfree_sensitive(subreq->iv);} static void seqiv_aead_encrypt_complete(struct crypto_async_request *base,					int err){	struct aead_request *req = base->data; 	seqiv_aead_encrypt_complete2(req, err);	aead_request_complete(req, err);} static int seqiv_aead_encrypt(struct aead_request *req){	struct crypto_aead *geniv = crypto_aead_reqtfm(req);	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);	struct aead_request *subreq = aead_request_ctx(req);	crypto_completion_t compl;	void *data;	u8 *info;	unsigned int ivsize = 8;	int err; 	if (req->cryptlen < ivsize)		return -EINVAL; 	aead_request_set_tfm(subreq, ctx->child); 	compl = req->base.complete;	data = req->base.data;	info = req->iv; 	if (req->src != req->dst) {		SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull); 		skcipher_request_set_sync_tfm(nreq, ctx->sknull);		skcipher_request_set_callback(nreq, req->base.flags,					      NULL, NULL);		skcipher_request_set_crypt(nreq, req->src, req->dst,					   req->assoclen + req->cryptlen,					   NULL); 		err = crypto_skcipher_encrypt(nreq);		if (err)			return err;	} 	if (unlikely(!IS_ALIGNED((unsigned long)info,				 crypto_aead_alignmask(geniv) + 1))) {		info = kmemdup(req->iv, ivsize, req->base.flags &			       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :			       GFP_ATOMIC);		if (!info)			return -ENOMEM; 		compl = seqiv_aead_encrypt_complete;		data = req;	} 	aead_request_set_callback(subreq, req->base.flags, compl, data);	aead_request_set_crypt(subreq, req->dst, req->dst,			       req->cryptlen - ivsize, info);	aead_request_set_ad(subreq, req->assoclen + ivsize); 	crypto_xor(info, ctx->salt, ivsize);	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1); 	err = crypto_aead_encrypt(subreq);	if (unlikely(info != req->iv))		seqiv_aead_encrypt_complete2(req, err);	return err;} static int seqiv_aead_decrypt(struct aead_request *req){	struct crypto_aead *geniv = crypto_aead_reqtfm(req);	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);	struct aead_request *subreq = aead_request_ctx(req);	crypto_completion_t compl;	void *data;	unsigned int ivsize = 8; 	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))		return -EINVAL; 	aead_request_set_tfm(subreq, ctx->child); 	compl = req->base.complete;	data = req->base.data; 	aead_request_set_callback(subreq, req->base.flags, compl, data);	aead_request_set_crypt(subreq, req->src, req->dst,			       req->cryptlen - ivsize, req->iv);	aead_request_set_ad(subreq, req->assoclen + ivsize); 	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0); 	return crypto_aead_decrypt(subreq);} static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb){	struct aead_instance *inst;	int err; 	inst = aead_geniv_alloc(tmpl, tb); 	if (IS_ERR(inst))		return PTR_ERR(inst); 	err = -EINVAL;	if (inst->alg.ivsize != sizeof(u64))		goto free_inst; 	inst->alg.encrypt = seqiv_aead_encrypt;	inst->alg.decrypt = seqiv_aead_decrypt; 	inst->alg.init = aead_init_geniv;	inst->alg.exit = aead_exit_geniv; 	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);	inst->alg.base.cra_ctxsize += inst->alg.ivsize; 	err = aead_register_instance(tmpl, inst);	if (err) {free_inst:		inst->free(inst);	}	return err;} static struct crypto_template seqiv_tmpl = {	.name = "seqiv",	.create = seqiv_aead_create,	.module = THIS_MODULE,}; static int __init seqiv_module_init(void){	return crypto_register_template(&seqiv_tmpl);} static void __exit seqiv_module_exit(void){	crypto_unregister_template(&seqiv_tmpl);} subsys_initcall(seqiv_module_init);module_exit(seqiv_module_exit); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Sequence Number IV Generator");MODULE_ALIAS_CRYPTO("seqiv");