linux-imx

// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * 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 <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 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) {

        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;

    }

​

    aead_request_set_callback(subreq, req->base.flags,

                  req->base.complete, req->base.data);

    aead_request_set_crypt(subreq, req->dst, req->dst,

                   req->cryptlen, info);

    aead_request_set_ad(subreq, req->assoclen);