[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>

4 files changed, 400 insertions, 0 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index a20a3f14d324..620e14cabdc6 100644
--- a/crypto/Kconfig
+++ b/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
diff --git a/crypto/Makefile b/crypto/Makefile
index 3820d4c5ccc2..cce46a1c9dc7 100644
--- a/crypto/Makefile
+++ b/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
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
new file mode 100644
index 000000000000..3ff4e1f0f032
--- /dev/null
+++ b/crypto/cryptd.c
@@ -0,0 +1,375 @@
+/*
+ * 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");
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 7847fc2a03f0..b2b1e6efd812 100644
--- a/include/crypto/algapi.h
+++ b/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);