Initial import

1 files changed, 270 insertions, 0 deletions

diff --git a/crypto/eseqiv.c b/crypto/eseqiv.c
new file mode 100644
index 000000000..f116fae76
--- /dev/null
+++ b/crypto/eseqiv.c
@@ -0,0 +1,270 @@
+/*
+ * 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");