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![Eric Biggers](/assets/img/avatar_default.png)
Convert the "seqiv" template to the new way of freeing instances where a ->free() method is installed to the instance struct itself. Also remove the unused implementation of the old way of freeing instances from the "echainiv" template, since it's already using the new way too. In doing this, also simplify the code by making the helper function aead_geniv_alloc() install the ->free() method, instead of making seqiv and echainiv do this themselves. This is analogous to how skcipher_alloc_instance_simple() works. This will allow removing support for the old way of freeing instances. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
165 lines
4.1 KiB
C
165 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* echainiv: Encrypted Chain IV Generator
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*
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* This generator generates an IV based on a sequence number by multiplying
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* it with a salt and then encrypting it with the same key as used to encrypt
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* the plain text. This algorithm requires that the block size be equal
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* to the IV size. It is mainly useful for CBC.
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*
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* This generator can only be used by algorithms where authentication
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* is performed after encryption (i.e., authenc).
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*
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* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <crypto/internal/geniv.h>
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#include <crypto/scatterwalk.h>
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#include <crypto/skcipher.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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static int echainiv_encrypt(struct aead_request *req)
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{
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struct crypto_aead *geniv = crypto_aead_reqtfm(req);
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struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
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struct aead_request *subreq = aead_request_ctx(req);
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__be64 nseqno;
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u64 seqno;
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u8 *info;
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unsigned int ivsize = crypto_aead_ivsize(geniv);
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int err;
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if (req->cryptlen < ivsize)
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return -EINVAL;
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aead_request_set_tfm(subreq, ctx->child);
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info = req->iv;
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if (req->src != req->dst) {
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SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
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skcipher_request_set_sync_tfm(nreq, ctx->sknull);
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skcipher_request_set_callback(nreq, req->base.flags,
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NULL, NULL);
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skcipher_request_set_crypt(nreq, req->src, req->dst,
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req->assoclen + req->cryptlen,
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NULL);
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err = crypto_skcipher_encrypt(nreq);
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if (err)
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return err;
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}
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aead_request_set_callback(subreq, req->base.flags,
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req->base.complete, req->base.data);
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aead_request_set_crypt(subreq, req->dst, req->dst,
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req->cryptlen, info);
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aead_request_set_ad(subreq, req->assoclen);
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memcpy(&nseqno, info + ivsize - 8, 8);
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seqno = be64_to_cpu(nseqno);
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memset(info, 0, ivsize);
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scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
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do {
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u64 a;
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memcpy(&a, ctx->salt + ivsize - 8, 8);
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a |= 1;
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a *= seqno;
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memcpy(info + ivsize - 8, &a, 8);
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} while ((ivsize -= 8));
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return crypto_aead_encrypt(subreq);
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}
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static int echainiv_decrypt(struct aead_request *req)
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{
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struct crypto_aead *geniv = crypto_aead_reqtfm(req);
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struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
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struct aead_request *subreq = aead_request_ctx(req);
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crypto_completion_t compl;
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void *data;
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unsigned int ivsize = crypto_aead_ivsize(geniv);
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if (req->cryptlen < ivsize)
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return -EINVAL;
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aead_request_set_tfm(subreq, ctx->child);
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compl = req->base.complete;
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data = req->base.data;
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aead_request_set_callback(subreq, req->base.flags, compl, data);
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aead_request_set_crypt(subreq, req->src, req->dst,
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req->cryptlen - ivsize, req->iv);
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aead_request_set_ad(subreq, req->assoclen + ivsize);
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scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
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return crypto_aead_decrypt(subreq);
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}
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static int echainiv_aead_create(struct crypto_template *tmpl,
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struct rtattr **tb)
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{
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struct aead_instance *inst;
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int err;
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inst = aead_geniv_alloc(tmpl, tb, 0, 0);
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if (IS_ERR(inst))
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return PTR_ERR(inst);
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err = -EINVAL;
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if (inst->alg.ivsize & (sizeof(u64) - 1) || !inst->alg.ivsize)
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goto free_inst;
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inst->alg.encrypt = echainiv_encrypt;
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inst->alg.decrypt = echainiv_decrypt;
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inst->alg.init = aead_init_geniv;
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inst->alg.exit = aead_exit_geniv;
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inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
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inst->alg.base.cra_ctxsize += inst->alg.ivsize;
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err = aead_register_instance(tmpl, inst);
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if (err) {
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free_inst:
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inst->free(inst);
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}
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return err;
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}
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static struct crypto_template echainiv_tmpl = {
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.name = "echainiv",
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.create = echainiv_aead_create,
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.module = THIS_MODULE,
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};
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static int __init echainiv_module_init(void)
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{
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return crypto_register_template(&echainiv_tmpl);
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}
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static void __exit echainiv_module_exit(void)
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{
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crypto_unregister_template(&echainiv_tmpl);
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}
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subsys_initcall(echainiv_module_init);
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module_exit(echainiv_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Encrypted Chain IV Generator");
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MODULE_ALIAS_CRYPTO("echainiv");
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