--- /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_givencrypt_first(struct skcipher_givcrypt_request *req)
+{
+ struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+ struct eseqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+ int err = 0;
+
+ spin_lock_bh(&ctx->lock);
+ if (crypto_ablkcipher_crt(geniv)->givencrypt != eseqiv_givencrypt_first)
+ goto unlock;
+
+ crypto_ablkcipher_crt(geniv)->givencrypt = eseqiv_givencrypt;
+ err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
+ crypto_ablkcipher_ivsize(geniv));
+
+unlock:
+ spin_unlock_bh(&ctx->lock);
+
+ if (err)
+ return err;
+
+ return eseqiv_givencrypt(req);
+}
+
+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;
+
+ 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);
+
+ return 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;
+
+ err = crypto_get_default_rng();
+ if (err)
+ return ERR_PTR(err);
+
+ inst = skcipher_geniv_alloc(&eseqiv_tmpl, tb, 0, 0);
+ if (IS_ERR(inst))
+ goto put_rng;
+
+ err = -EINVAL;
+ if (inst->alg.cra_ablkcipher.ivsize != inst->alg.cra_blocksize)
+ goto free_inst;
+
+ inst->alg.cra_ablkcipher.givencrypt = eseqiv_givencrypt_first;
+
+ 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);
+put_rng:
+ crypto_put_default_rng();
+ goto out;
+}
+
+static void eseqiv_free(struct crypto_instance *inst)
+{
+ skcipher_geniv_free(inst);
+ crypto_put_default_rng();
+}
+
+static struct crypto_template eseqiv_tmpl = {
+ .name = "eseqiv",
+ .alloc = eseqiv_alloc,
+ .free = eseqiv_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");
Code Review / kvmfornfv.git / blobdiff