2.6.25-rc7

 crypto

diff --git a/crypto/chainiv.c b/crypto/chainiv.c
new file mode 100644
index 0000000..6da3f57
--- /dev/null
+++ b/crypto/chainiv.c
@@ -0,0 +1,325 @@
+/*
+ * chainiv: Chain IV Generator
+ *
+ * Generate IVs simply be using the last block of the previous encryption.
+ * This is mainly useful for CBC with a synchronous algorithm.
+ *
+ * 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 <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/workqueue.h>
+
+enum {
+   CHAINIV_STATE_INUSE = 0,
+};
+
+struct chainiv_ctx {
+   spinlock_t lock;
+   char iv[];
+};
+
+struct async_chainiv_ctx {
+   unsigned long state;
+
+   spinlock_t lock;
+   int err;
+
+   struct crypto_queue queue;
+   struct work_struct postponed;
+
+   char iv[];
+};
+
+static int chainiv_givencrypt(struct skcipher_givcrypt_request *req)
+{
+   struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+   struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+   struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
+   unsigned int ivsize;
+   int err;
+
+   ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
+   ablkcipher_request_set_callback(subreq, req->creq.base.flags &
+                  ~CRYPTO_TFM_REQ_MAY_SLEEP,
+               req->creq.base.complete,
+               req->creq.base.data);
+   ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
+                 req->creq.nbytes, req->creq.info);
+
+   spin_lock_bh(&ctx->lock);
+
+   ivsize = crypto_ablkcipher_ivsize(geniv);
+
+   memcpy(req->giv, ctx->iv, ivsize);
+   memcpy(subreq->info, ctx->iv, ivsize);
+
+   err = crypto_ablkcipher_encrypt(subreq);
+   if (err)
+      goto unlock;
+
+   memcpy(ctx->iv, subreq->info, ivsize);
+
+unlock:
+   spin_unlock_bh(&ctx->lock);
+
+   return err;
+}
+
+static int chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
+{
+   struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+   struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+
+   spin_lock_bh(&ctx->lock);
+   if (crypto_ablkcipher_crt(geniv)->givencrypt !=
+       chainiv_givencrypt_first)
+      goto unlock;
+
+   crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
+   get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));
+
+unlock:
+   spin_unlock_bh(&ctx->lock);
+
+   return chainiv_givencrypt(req);
+}
+
+static int chainiv_init_common(struct crypto_tfm *tfm)
+{
+   tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
+
+   return skcipher_geniv_init(tfm);
+}
+
+static int chainiv_init(struct crypto_tfm *tfm)
+{
+   struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
+
+   spin_lock_init(&ctx->lock);
+
+   return chainiv_init_common(tfm);
+}
+
+static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
+{
+   int queued;
+
+   if (!ctx->queue.qlen) {
+      smp_mb__before_clear_bit();
+      clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
+
+      if (!ctx->queue.qlen ||
+          test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
+         goto out;
+   }
+
+   queued = schedule_work(&ctx->postponed);
+   BUG_ON(!queued);
+
+out:
+   return ctx->err;
+}
+
+static int async_chainiv_postpone_request(struct skcipher_givcrypt_request *req)
+{
+   struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+   struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+   int err;
+
+   spin_lock_bh(&ctx->lock);
+   err = skcipher_enqueue_givcrypt(&ctx->queue, req);
+   spin_unlock_bh(&ctx->lock);
+
+   if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
+      return err;
+
+   ctx->err = err;
+   return async_chainiv_schedule_work(ctx);
+}
+
+static int async_chainiv_givencrypt_tail(struct skcipher_givcrypt_request *req)
+{
+   struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+   struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+   struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
+   unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);
+
+   memcpy(req->giv, ctx->iv, ivsize);
+   memcpy(subreq->info, ctx->iv, ivsize);
+
+   ctx->err = crypto_ablkcipher_encrypt(subreq);
+   if (ctx->err)
+      goto out;
+
+   memcpy(ctx->iv, subreq->info, ivsize);
+
+out:
+   return async_chainiv_schedule_work(ctx);
+}
+
+static int async_chainiv_givencrypt(struct skcipher_givcrypt_request *req)
+{
+   struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+   struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+   struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
+
+   ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
+   ablkcipher_request_set_callback(subreq, req->creq.base.flags,
+               req->creq.base.complete,
+               req->creq.base.data);
+   ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
+                 req->creq.nbytes, req->creq.info);
+
+   if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
+      goto postpone;
+
+   if (ctx->queue.qlen) {
+      clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
+      goto postpone;
+   }
+
+   return async_chainiv_givencrypt_tail(req);
+
+postpone:
+   return async_chainiv_postpone_request(req);
+}
+
+static int async_chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
+{
+   struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
+   struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
+
+   if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
+      goto out;
+
+   if (crypto_ablkcipher_crt(geniv)->givencrypt !=
+       async_chainiv_givencrypt_first)
+      goto unlock;
+
+   crypto_ablkcipher_crt(geniv)->givencrypt = async_chainiv_givencrypt;
+   get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));
+
+unlock:
+   clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
+
+out:
+   return async_chainiv_givencrypt(req);
+}
+
+static void async_chainiv_do_postponed(struct work_struct *work)
+{
+   struct async_chainiv_ctx *ctx = container_of(work,
+                       struct async_chainiv_ctx,
+                       postponed);
+   struct skcipher_givcrypt_request *req;
+   struct ablkcipher_request *subreq;
+
+   /* Only handle one request at a time to avoid hogging keventd. */
+   spin_lock_bh(&ctx->lock);
+   req = skcipher_dequeue_givcrypt(&ctx->queue);
+   spin_unlock_bh(&ctx->lock);
+
+   if (!req) {
+      async_chainiv_schedule_work(ctx);
+      return;
+   }
+
+   subreq = skcipher_givcrypt_reqctx(req);
+   subreq->base.flags |= CRYPTO_TFM_REQ_MAY_SLEEP;
+
+   async_chainiv_givencrypt_tail(req);
+}
+
+static int async_chainiv_init(struct crypto_tfm *tfm)
+{
+   struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
+
+   spin_lock_init(&ctx->lock);
+
+   crypto_init_queue(&ctx->queue, 100);
+   INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);
+
+   return chainiv_init_common(tfm);
+}
+
+static void async_chainiv_exit(struct crypto_tfm *tfm)
+{
+   struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
+
+   BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) || ctx->queue.qlen);
+
+   skcipher_geniv_exit(tfm);
+}
+
+static struct crypto_template chainiv_tmpl;
+
+static struct crypto_instance *chainiv_alloc(struct rtattr **tb)
+{
+   struct crypto_attr_type *algt;
+   struct crypto_instance *inst;
+   int err;
+
+   algt = crypto_get_attr_type(tb);
+   err = PTR_ERR(algt);
+   if (IS_ERR(algt))
+      return ERR_PTR(err);
+
+   inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
+   if (IS_ERR(inst))
+      goto out;
+
+   inst->alg.cra_ablkcipher.givencrypt = chainiv_givencrypt_first;
+
+   inst->alg.cra_init = chainiv_init;
+   inst->alg.cra_exit = skcipher_geniv_exit;
+
+   inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);
+
+   if (!crypto_requires_sync(algt->type, algt->mask)) {
+      inst->alg.cra_flags |= CRYPTO_ALG_ASYNC;
+
+      inst->alg.cra_ablkcipher.givencrypt =
+         async_chainiv_givencrypt_first;
+
+      inst->alg.cra_init = async_chainiv_init;
+      inst->alg.cra_exit = async_chainiv_exit;
+
+      inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
+   }
+
+   inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
+
+out:
+   return inst;
+}
+
+static struct crypto_template chainiv_tmpl = {
+   .name = "chainiv",
+   .alloc = chainiv_alloc,
+   .free = skcipher_geniv_free,
+   .module = THIS_MODULE,
+};
+
+int __init chainiv_module_init(void)
+{
+   return crypto_register_template(&chainiv_tmpl);
+}
+
+void chainiv_module_exit(void)
+{
+   crypto_unregister_template(&chainiv_tmpl);
+}