+++ /dev/null
-/*
- * eseqiv: Encrypted Sequence Number IV Generator
- *
- * This generator generates an IV based on a sequence number by xoring 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.
- *
- * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
- *
- * 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/skcipher.h>
-#include <crypto/rng.h>
-#include <crypto/scatterwalk.h>
-#include <linux/err.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/scatterlist.h>
-#include <linux/spinlock.h>
-#include <linux/string.h>
-
-struct eseqiv_request_ctx {
- struct scatterlist src[2];
- struct scatterlist dst[2];
- char tail[];
-};
-
-struct eseqiv_ctx {
- spinlock_t lock;
- unsigned int reqoff;
- char salt[];
-};
-
-static void eseqiv_complete2(struct skcipher_givcrypt_request *req)
-{
- struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
- struct eseqiv_request_ctx *reqctx = skcipher_givcrypt_reqctx(req);
-
- memcpy(req->giv, PTR_ALIGN((u8 *)reqctx->tail,
- crypto_ablkcipher_alignmask(geniv) + 1),
- crypto_ablkcipher_ivsize(geniv));
-}
-
-static void eseqiv_complete(struct crypto_async_request *base, int err)
-{
- struct skcipher_givcrypt_request *req = base->data;
-
- if (err)
- goto out;
-
- eseqiv_complete2(req);
-
-out:
- skcipher_givcrypt_complete(req, err);
-}
-
-static int eseqiv_givencrypt(struct skcipher_givcrypt_request *req)
-{
- struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
- struct eseqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
- struct eseqiv_request_ctx *reqctx = skcipher_givcrypt_reqctx(req);
- struct ablkcipher_request *subreq;
- crypto_completion_t compl;
- void *data;
- struct scatterlist *osrc, *odst;
- struct scatterlist *dst;
- struct page *srcp;
- struct page *dstp;
- u8 *giv;
- u8 *vsrc;
- u8 *vdst;
- __be64 seq;
- unsigned int ivsize;
- unsigned int len;
- int err;
-
- subreq = (void *)(reqctx->tail + ctx->reqoff);
- ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
-
- giv = req->giv;
- compl = req->creq.base.complete;
- data = req->creq.base.data;
-
- osrc = req->creq.src;
- odst = req->creq.dst;
- srcp = sg_page(osrc);
- dstp = sg_page(odst);
- vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + osrc->offset;
- vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + odst->offset;
-
- ivsize = crypto_ablkcipher_ivsize(geniv);
-
- if (vsrc != giv + ivsize && vdst != giv + ivsize) {
- giv = PTR_ALIGN((u8 *)reqctx->tail,
- crypto_ablkcipher_alignmask(geniv) + 1);
- compl = eseqiv_complete;
- data = req;
- }
-
- ablkcipher_request_set_callback(subreq, req->creq.base.flags, compl,
- data);
-
- sg_init_table(reqctx->src, 2);
- sg_set_buf(reqctx->src, giv, ivsize);
- scatterwalk_crypto_chain(reqctx->src, osrc, vsrc == giv + ivsize, 2);
-
- dst = reqctx->src;
- if (osrc != odst) {
- sg_init_table(reqctx->dst, 2);
- sg_set_buf(reqctx->dst, giv, ivsize);
- scatterwalk_crypto_chain(reqctx->dst, odst, vdst == giv + ivsize, 2);
-
- dst = reqctx->dst;
- }
-
- ablkcipher_request_set_crypt(subreq, reqctx->src, dst,
- req->creq.nbytes + ivsize,
- req->creq.info);
-
- memcpy(req->creq.info, ctx->salt, ivsize);
-
- len = ivsize;
- if (ivsize > sizeof(u64)) {
- memset(req->giv, 0, ivsize - sizeof(u64));
- len = sizeof(u64);
- }
- seq = cpu_to_be64(req->seq);
- memcpy(req->giv + ivsize - len, &seq, len);
-
- err = crypto_ablkcipher_encrypt(subreq);
- if (err)
- goto out;
-
- if (giv != req->giv)
- eseqiv_complete2(req);
-
-out:
- return err;
-}
-
-static int eseqiv_init(struct crypto_tfm *tfm)
-{
- struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
- struct eseqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
- unsigned long alignmask;
- unsigned int reqsize;
- int err;
-
- spin_lock_init(&ctx->lock);
-
- alignmask = crypto_tfm_ctx_alignment() - 1;
- reqsize = sizeof(struct eseqiv_request_ctx);
-
- if (alignmask & reqsize) {
- alignmask &= reqsize;
- alignmask--;
- }
-
- alignmask = ~alignmask;
- alignmask &= crypto_ablkcipher_alignmask(geniv);
-
- reqsize += alignmask;
- reqsize += crypto_ablkcipher_ivsize(geniv);
- reqsize = ALIGN(reqsize, crypto_tfm_ctx_alignment());
-
- ctx->reqoff = reqsize - sizeof(struct eseqiv_request_ctx);
-
- tfm->crt_ablkcipher.reqsize = reqsize +
- sizeof(struct ablkcipher_request);
-
- err = 0;
- if (!crypto_get_default_rng()) {
- crypto_ablkcipher_crt(geniv)->givencrypt = eseqiv_givencrypt;
- err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
- crypto_ablkcipher_ivsize(geniv));
- crypto_put_default_rng();
- }
-
- return err ?: skcipher_geniv_init(tfm);
-}
-
-static struct crypto_template eseqiv_tmpl;
-
-static struct crypto_instance *eseqiv_alloc(struct rtattr **tb)
-{
- struct crypto_instance *inst;
- int err;
-
- inst = skcipher_geniv_alloc(&eseqiv_tmpl, tb, 0, 0);
- if (IS_ERR(inst))
- goto out;
-
- err = -EINVAL;
- if (inst->alg.cra_ablkcipher.ivsize != inst->alg.cra_blocksize)
- goto free_inst;
-
- inst->alg.cra_init = eseqiv_init;
- inst->alg.cra_exit = skcipher_geniv_exit;
-
- inst->alg.cra_ctxsize = sizeof(struct eseqiv_ctx);
- inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
-
-out:
- return inst;
-
-free_inst:
- skcipher_geniv_free(inst);
- inst = ERR_PTR(err);
- goto out;
-}
-
-static struct crypto_template eseqiv_tmpl = {
- .name = "eseqiv",
- .alloc = eseqiv_alloc,
- .free = skcipher_geniv_free,
- .module = THIS_MODULE,
-};
-
-static int __init eseqiv_module_init(void)
-{
- return crypto_register_template(&eseqiv_tmpl);
-}
-
-static void __exit eseqiv_module_exit(void)
-{
- crypto_unregister_template(&eseqiv_tmpl);
-}
-
-module_init(eseqiv_module_init);
-module_exit(eseqiv_module_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Encrypted Sequence Number IV Generator");
-MODULE_ALIAS_CRYPTO("eseqiv");
projects / linux-2.6-block.git / blobdiff