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Release 4.8 crypto/echainiv.c

Directory: crypto
 * echainiv: Encrypted Chain IV Generator
 * This generator generates an IV based on a sequence number by multiplying
 * it with a salt and then encrypting it with the same key as used to encrypt
 * the plain text.  This algorithm requires that the block size be equal
 * to the IV size.  It is mainly useful for CBC.
 * This generator can only be used by algorithms where authentication
 * is performed after encryption (i.e., authenc).
 * Copyright (c) 2015 Herbert Xu <>
 * 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/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 int echainiv_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); __be64 nseqno; u64 seqno; u8 *info; unsigned int ivsize = crypto_aead_ivsize(geniv); int err; if (req->cryptlen < ivsize) return -EINVAL; aead_request_set_tfm(subreq, ctx->child); info = req->iv; if (req->src != req->dst) { SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull); skcipher_request_set_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; } aead_request_set_callback(subreq, req->base.flags, req->base.complete, req->; aead_request_set_crypt(subreq, req->dst, req->dst, req->cryptlen, info); aead_request_set_ad(subreq, req->assoclen); memcpy(&nseqno, info + ivsize - 8, 8); seqno = be64_to_cpu(nseqno); memset(info, 0, ivsize); scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1); do { u64 a; memcpy(&a, ctx->salt + ivsize - 8, 8); a |= 1; a *= seqno; memcpy(info + ivsize - 8, &a, 8); } while ((ivsize -= 8)); return crypto_aead_encrypt(subreq); }


herbert xuherbert xu329100.00%6100.00%

static int echainiv_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 = crypto_aead_ivsize(geniv); if (req->cryptlen < ivsize) return -EINVAL; aead_request_set_tfm(subreq, ctx->child); compl = req->base.complete; data = req->; 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); }


herbert xuherbert xu168100.00%4100.00%

static int echainiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb) { struct aead_instance *inst; struct crypto_aead_spawn *spawn; struct aead_alg *alg; int err; inst = aead_geniv_alloc(tmpl, tb, 0, 0); if (IS_ERR(inst)) return PTR_ERR(inst); spawn = aead_instance_ctx(inst); alg = crypto_spawn_aead_alg(spawn); err = -EINVAL; if (inst->alg.ivsize & (sizeof(u64) - 1) || !inst->alg.ivsize) goto free_inst; inst->alg.encrypt = echainiv_encrypt; inst->alg.decrypt = echainiv_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; inst->free = aead_geniv_free; err = aead_register_instance(tmpl, inst); if (err) goto free_inst; out: return err; free_inst: aead_geniv_free(inst); goto out; }


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static void echainiv_free(struct crypto_instance *inst) { aead_geniv_free(aead_instance(inst)); }


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static struct crypto_template echainiv_tmpl = { .name = "echainiv", .create = echainiv_aead_create, .free = echainiv_free, .module = THIS_MODULE, };
static int __init echainiv_module_init(void) { return crypto_register_template(&echainiv_tmpl); }


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static void __exit echainiv_module_exit(void) { crypto_unregister_template(&echainiv_tmpl); }


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module_init(echainiv_module_init); module_exit(echainiv_module_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Encrypted Chain IV Generator"); MODULE_ALIAS_CRYPTO("echainiv");

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herbert xuherbert xu831100.00%10100.00%
Directory: crypto
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