2.6.25

 crypto

diff --git a/crypto/eseqiv.c b/crypto/eseqiv.c
new file mode 100644
index 0000000..b14f14e
--- /dev/null
+++ b/crypto/eseqiv.c
@@ -0,0 +1,258 @@
+/*
+ * 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/scatterwalk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/random.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 void eseqiv_chain(struct scatterlist *head, struct scatterlist *sg,
+          int chain)
+{
+   if (chain) {
+      head->length += sg->length;
+      sg = scatterwalk_sg_next(sg);
+   }
+
+   if (sg)
+      scatterwalk_sg_chain(head, 2, sg);
+   else
+      sg_mark_end(head);
+}
+
+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 complete;
+   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;
+   complete = 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);
+      complete = eseqiv_complete;
+      data = req;
+   }
+
+   ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete,
+               data);
+
+   sg_init_table(reqctx->src, 2);
+   sg_set_buf(reqctx->src, giv, ivsize);
+   eseqiv_chain(reqctx->src, osrc, vsrc == giv + ivsize);
+
+   dst = reqctx->src;
+   if (osrc != odst) {
+      sg_init_table(reqctx->dst, 2);
+      sg_set_buf(reqctx->dst, giv, ivsize);
+      eseqiv_chain(reqctx->dst, odst, vdst == giv + ivsize);
+
+      dst = reqctx->dst;
+   }
+
+   ablkcipher_request_set_crypt(subreq, reqctx->src, dst,
+                 req->creq.nbytes, 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;
+
+   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);
+
+   spin_lock_bh(&ctx->lock);
+   if (crypto_ablkcipher_crt(geniv)->givencrypt != eseqiv_givencrypt_first)
+      goto unlock;
+
+   crypto_ablkcipher_crt(geniv)->givencrypt = eseqiv_givencrypt;
+   get_random_bytes(ctx->salt, crypto_ablkcipher_ivsize(geniv));
+
+unlock:
+   spin_unlock_bh(&ctx->lock);
+
+   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;
+
+   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_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);
+   goto out;
+}
+
+static struct crypto_template eseqiv_tmpl = {
+   .name = "eseqiv",
+   .alloc = eseqiv_alloc,
+   .free = skcipher_geniv_free,
+   .module = THIS_MODULE,
+};
+
+int __init eseqiv_module_init(void)
+{
+   return crypto_register_template(&eseqiv_tmpl);
+}
+
+void __exit eseqiv_module_exit(void)
+{
+   crypto_unregister_template(&eseqiv_tmpl);
+}