[CRYPTO] cryptd: Add software async crypto daemon

This patch adds the cryptd module which is a template that takes a
synchronous software crypto algorithm and converts it to an asynchronous
one by executing it in a kernel thread.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -175,6 +175,15 @@ config CRYPTO_LRW
 	  The first 128, 192 or 256 bits in the key are used for AES and the
 	  rest is used to tie each cipher block to its logical position.
 
+config CRYPTO_CRYPTD
+	tristate "Software async crypto daemon"
+	select CRYPTO_ABLKCIPHER
+	select CRYPTO_MANAGER
+	help
+	  This is a generic software asynchronous crypto daemon that
+	  converts an arbitrary synchronous software crypto algorithm
+	  into an asynchronous algorithm that executes in a kernel thread.
+
 config CRYPTO_DES
 	tristate "DES and Triple DES EDE cipher algorithms"
 	select CRYPTO_ALGAPI

crypto/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_CRYPTO_ECB) += ecb.o
 obj-$(CONFIG_CRYPTO_CBC) += cbc.o
 obj-$(CONFIG_CRYPTO_PCBC) += pcbc.o
 obj-$(CONFIG_CRYPTO_LRW) += lrw.o
+obj-$(CONFIG_CRYPTO_CRYPTD) += cryptd.o
 obj-$(CONFIG_CRYPTO_DES) += des.o
 obj-$(CONFIG_CRYPTO_FCRYPT) += fcrypt.o
 obj-$(CONFIG_CRYPTO_BLOWFISH) += blowfish.o

crypto/cryptd.c

+/*
+ * Software async crypto daemon.
+ *
+ * Copyright (c) 2006 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/algapi.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#define CRYPTD_MAX_QLEN 100
+
+struct cryptd_state {
+	spinlock_t lock;
+	struct mutex mutex;
+	struct crypto_queue queue;
+	struct task_struct *task;
+};
+
+struct cryptd_instance_ctx {
+	struct crypto_spawn spawn;
+	struct cryptd_state *state;
+};
+
+struct cryptd_blkcipher_ctx {
+	struct crypto_blkcipher *child;
+};
+
+struct cryptd_blkcipher_request_ctx {
+	crypto_completion_t complete;
+};
+
+
+static inline struct cryptd_state *cryptd_get_state(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
+	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
+	return ictx->state;
+}
+
+static int cryptd_blkcipher_setkey(struct crypto_ablkcipher *parent,
+				   const u8 *key, unsigned int keylen)
+{
+	struct cryptd_blkcipher_ctx *ctx = crypto_ablkcipher_ctx(parent);
+	struct crypto_blkcipher *child = ctx->child;
+	int err;
+
+	crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+	crypto_blkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
+					  CRYPTO_TFM_REQ_MASK);
+	err = crypto_blkcipher_setkey(child, key, keylen);
+	crypto_ablkcipher_set_flags(parent, crypto_blkcipher_get_flags(child) &
+					    CRYPTO_TFM_RES_MASK);
+	return err;
+}
+
+static void cryptd_blkcipher_crypt(struct ablkcipher_request *req,
+				   struct crypto_blkcipher *child,
+				   int err,
+				   int (*crypt)(struct blkcipher_desc *desc,
+						struct scatterlist *dst,
+						struct scatterlist *src,
+						unsigned int len))
+{
+	struct cryptd_blkcipher_request_ctx *rctx;
+	struct blkcipher_desc desc;
+
+	rctx = ablkcipher_request_ctx(req);
+
+	if (unlikely(err == -EINPROGRESS)) {
+		rctx->complete(&req->base, err);
+		return;
+	}
+
+	desc.tfm = child;
+	desc.info = req->info;
+	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	err = crypt(&desc, req->dst, req->src, req->nbytes);
+
+	req->base.complete = rctx->complete;
+
+	local_bh_disable();
+	req->base.complete(&req->base, err);
+	local_bh_enable();
+}
+
+static void cryptd_blkcipher_encrypt(struct crypto_async_request *req, int err)
+{
+	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
+	struct crypto_blkcipher *child = ctx->child;
+
+	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
+			       crypto_blkcipher_crt(child)->encrypt);
+}
+
+static void cryptd_blkcipher_decrypt(struct crypto_async_request *req, int err)
+{
+	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
+	struct crypto_blkcipher *child = ctx->child;
+
+	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
+			       crypto_blkcipher_crt(child)->decrypt);
+}
+
+static int cryptd_blkcipher_enqueue(struct ablkcipher_request *req,
+				    crypto_completion_t complete)
+{
+	struct cryptd_blkcipher_request_ctx *rctx = ablkcipher_request_ctx(req);
+	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
+	struct cryptd_state *state =
+		cryptd_get_state(crypto_ablkcipher_tfm(tfm));
+	int err;
+
+	rctx->complete = req->base.complete;
+	req->base.complete = complete;
+
+	spin_lock_bh(&state->lock);
+	err = ablkcipher_enqueue_request(crypto_ablkcipher_alg(tfm), req);
+	spin_unlock_bh(&state->lock);
+
+	wake_up_process(state->task);
+	return err;
+}
+
+static int cryptd_blkcipher_encrypt_enqueue(struct ablkcipher_request *req)
+{
+	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_encrypt);
+}
+
+static int cryptd_blkcipher_decrypt_enqueue(struct ablkcipher_request *req)
+{
+	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_decrypt);
+}
+
+static int cryptd_blkcipher_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
+	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
+	struct crypto_spawn *spawn = &ictx->spawn;
+	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct crypto_blkcipher *cipher;
+
+	cipher = crypto_spawn_blkcipher(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+	tfm->crt_ablkcipher.reqsize =
+		sizeof(struct cryptd_blkcipher_request_ctx);
+	return 0;
+}
+
+static void cryptd_blkcipher_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct cryptd_state *state = cryptd_get_state(tfm);
+	int active;
+
+	mutex_lock(&state->mutex);
+	active = ablkcipher_tfm_in_queue(__crypto_ablkcipher_cast(tfm));
+	mutex_unlock(&state->mutex);
+
+	BUG_ON(active);
+
+	crypto_free_blkcipher(ctx->child);
+}
+
+static struct crypto_instance *cryptd_alloc_instance(struct crypto_alg *alg,
+						     struct cryptd_state *state)
+{
+	struct crypto_instance *inst;
+	struct cryptd_instance_ctx *ctx;
+	int err;
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
+	if (IS_ERR(inst))
+		goto out;
+
+	err = -ENAMETOOLONG;
+	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+		     "cryptd(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
+		goto out_free_inst;
+
+	ctx = crypto_instance_ctx(inst);
+	err = crypto_init_spawn(&ctx->spawn, alg, inst,
+				CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
+	if (err)
+		goto out_free_inst;
+
+	ctx->state = state;
+
+	memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
+
+	inst->alg.cra_priority = alg->cra_priority + 50;
+	inst->alg.cra_blocksize = alg->cra_blocksize;
+	inst->alg.cra_alignmask = alg->cra_alignmask;
+
+out:
+	return inst;
+
+out_free_inst:
+	kfree(inst);
+	inst = ERR_PTR(err);
+	goto out;
+}
+
+static struct crypto_instance *cryptd_alloc_blkcipher(
+	struct rtattr **tb, struct cryptd_state *state)
+{
+	struct crypto_instance *inst;
+	struct crypto_alg *alg;
+
+	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_BLKCIPHER,
+				  CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
+	if (IS_ERR(alg))
+		return ERR_PTR(PTR_ERR(alg));
+
+	inst = cryptd_alloc_instance(alg, state);
+	if (IS_ERR(inst))
+		goto out_put_alg;
+
+	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_ASYNC;
+	inst->alg.cra_type = &crypto_ablkcipher_type;
+
+	inst->alg.cra_ablkcipher.ivsize = alg->cra_blkcipher.ivsize;
+	inst->alg.cra_ablkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
+	inst->alg.cra_ablkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
+
+	inst->alg.cra_ctxsize = sizeof(struct cryptd_blkcipher_ctx);
+
+	inst->alg.cra_init = cryptd_blkcipher_init_tfm;
+	inst->alg.cra_exit = cryptd_blkcipher_exit_tfm;
+
+	inst->alg.cra_ablkcipher.setkey = cryptd_blkcipher_setkey;
+	inst->alg.cra_ablkcipher.encrypt = cryptd_blkcipher_encrypt_enqueue;
+	inst->alg.cra_ablkcipher.decrypt = cryptd_blkcipher_decrypt_enqueue;
+
+	inst->alg.cra_ablkcipher.queue = &state->queue;
+
+out_put_alg:
+	crypto_mod_put(alg);
+	return inst;
+}
+
+static struct cryptd_state state;
+
+static struct crypto_instance *cryptd_alloc(struct rtattr **tb)
+{
+	struct crypto_attr_type *algt;
+
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return ERR_PTR(PTR_ERR(algt));
+
+	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
+	case CRYPTO_ALG_TYPE_BLKCIPHER:
+		return cryptd_alloc_blkcipher(tb, &state);
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+static void cryptd_free(struct crypto_instance *inst)
+{
+	struct cryptd_instance_ctx *ctx = crypto_instance_ctx(inst);
+
+	crypto_drop_spawn(&ctx->spawn);
+	kfree(inst);
+}
+
+static struct crypto_template cryptd_tmpl = {
+	.name = "cryptd",
+	.alloc = cryptd_alloc,
+	.free = cryptd_free,
+	.module = THIS_MODULE,
+};
+
+static inline int cryptd_create_thread(struct cryptd_state *state,
+				       int (*fn)(void *data), const char *name)
+{
+	spin_lock_init(&state->lock);
+	mutex_init(&state->mutex);
+	crypto_init_queue(&state->queue, CRYPTD_MAX_QLEN);
+
+	state->task = kthread_create(fn, state, name);
+	if (IS_ERR(state->task))
+		return PTR_ERR(state->task);
+
+	return 0;
+}
+
+static inline void cryptd_stop_thread(struct cryptd_state *state)
+{
+	BUG_ON(state->queue.qlen);
+	kthread_stop(state->task);
+}
+
+static int cryptd_thread(void *data)
+{
+	struct cryptd_state *state = data;
+	int stop;
+
+	do {
+		struct crypto_async_request *req, *backlog;
+
+		mutex_lock(&state->mutex);
+		__set_current_state(TASK_INTERRUPTIBLE);
+
+		spin_lock_bh(&state->lock);
+		backlog = crypto_get_backlog(&state->queue);
+		req = crypto_dequeue_request(&state->queue);
+		spin_unlock_bh(&state->lock);
+
+		stop = kthread_should_stop();
+
+		if (stop || req) {
+			__set_current_state(TASK_RUNNING);
+			if (req) {
+				if (backlog)
+					backlog->complete(backlog,
+							  -EINPROGRESS);
+				req->complete(req, 0);
+			}
+		}
+
+		mutex_unlock(&state->mutex);
+
+		schedule();
+	} while (!stop);
+
+	return 0;
+}
+
+static int __init cryptd_init(void)
+{
+	int err;
+
+	err = cryptd_create_thread(&state, cryptd_thread, "cryptd");
+	if (err)
+		return err;
+
+	err = crypto_register_template(&cryptd_tmpl);
+	if (err)
+		kthread_stop(state.task);
+
+	return err;
+}
+
+static void __exit cryptd_exit(void)
+{
+	cryptd_stop_thread(&state);
+	crypto_unregister_template(&cryptd_tmpl);
+}
+
+module_init(cryptd_init);
+module_exit(cryptd_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Software async crypto daemon");

include/crypto/algapi.h

@@ -138,6 +138,12 @@ static inline void *crypto_tfm_ctx_aligned(struct crypto_tfm *tfm)
 	return (void *)ALIGN(addr, align);
 }
 
+static inline struct crypto_instance *crypto_tfm_alg_instance(
+	struct crypto_tfm *tfm)
+{
+	return container_of(tfm->__crt_alg, struct crypto_instance, alg);
+}
+
 static inline void *crypto_instance_ctx(struct crypto_instance *inst)
 {
 	return inst->__ctx;
@@ -154,6 +160,15 @@ static inline void *crypto_ablkcipher_ctx(struct crypto_ablkcipher *tfm)
 	return crypto_tfm_ctx(&tfm->base);
 }
 
+static inline struct crypto_blkcipher *crypto_spawn_blkcipher(
+	struct crypto_spawn *spawn)
+{
+	u32 type = CRYPTO_ALG_TYPE_BLKCIPHER;
+	u32 mask = CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC;
+
+	return __crypto_blkcipher_cast(crypto_spawn_tfm(spawn, type, mask));
+}
+
 static inline void *crypto_blkcipher_ctx(struct crypto_blkcipher *tfm)
 {
 	return crypto_tfm_ctx(&tfm->base);