// 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");