x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 1029 insertions, 0 deletions

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
new file mode 100644
index 000000000..d8dbf07ab
--- /dev/null
+++ b/crypto/cryptd.c
@@ -0,0 +1,1029 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Software async crypto daemon.
+ *
+ * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * Added AEAD support to cryptd.
+ *    Authors: Tadeusz Struk (tadeusz.struk@intel.com)
+ *             Adrian Hoban <adrian.hoban@intel.com>
+ *             Gabriele Paoloni <gabriele.paoloni@intel.com>
+ *             Aidan O'Mahony (aidan.o.mahony@intel.com)
+ *    Copyright (c) 2010, Intel Corporation.
+ */
+
+#include <crypto/internal/hash.h>
+#include <crypto/internal/aead.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/cryptd.h>
+#include <linux/refcount.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+static unsigned int cryptd_max_cpu_qlen = 1000;
+module_param(cryptd_max_cpu_qlen, uint, 0);
+MODULE_PARM_DESC(cryptd_max_cpu_qlen, "Set cryptd Max queue depth");
+
+static struct workqueue_struct *cryptd_wq;
+
+struct cryptd_cpu_queue {
+	local_lock_t bh_lock;
+	struct crypto_queue queue;
+	struct work_struct work;
+};
+
+struct cryptd_queue {
+	/*
+	 * Protected by disabling BH to allow enqueueing from softinterrupt and
+	 * dequeuing from kworker (cryptd_queue_worker()).
+	 */
+	struct cryptd_cpu_queue __percpu *cpu_queue;
+};
+
+struct cryptd_instance_ctx {
+	struct crypto_spawn spawn;
+	struct cryptd_queue *queue;
+};
+
+struct skcipherd_instance_ctx {
+	struct crypto_skcipher_spawn spawn;
+	struct cryptd_queue *queue;
+};
+
+struct hashd_instance_ctx {
+	struct crypto_shash_spawn spawn;
+	struct cryptd_queue *queue;
+};
+
+struct aead_instance_ctx {
+	struct crypto_aead_spawn aead_spawn;
+	struct cryptd_queue *queue;
+};
+
+struct cryptd_skcipher_ctx {
+	refcount_t refcnt;
+	struct crypto_skcipher *child;
+};
+
+struct cryptd_skcipher_request_ctx {
+	struct skcipher_request req;
+};
+
+struct cryptd_hash_ctx {
+	refcount_t refcnt;
+	struct crypto_shash *child;
+};
+
+struct cryptd_hash_request_ctx {
+	crypto_completion_t complete;
+	void *data;
+	struct shash_desc desc;
+};
+
+struct cryptd_aead_ctx {
+	refcount_t refcnt;
+	struct crypto_aead *child;
+};
+
+struct cryptd_aead_request_ctx {
+	struct aead_request req;
+};
+
+static void cryptd_queue_worker(struct work_struct *work);
+
+static int cryptd_init_queue(struct cryptd_queue *queue,
+			     unsigned int max_cpu_qlen)
+{
+	int cpu;
+	struct cryptd_cpu_queue *cpu_queue;
+
+	queue->cpu_queue = alloc_percpu(struct cryptd_cpu_queue);
+	if (!queue->cpu_queue)
+		return -ENOMEM;
+	for_each_possible_cpu(cpu) {
+		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
+		crypto_init_queue(&cpu_queue->queue, max_cpu_qlen);
+		INIT_WORK(&cpu_queue->work, cryptd_queue_worker);
+		local_lock_init(&cpu_queue->bh_lock);
+	}
+	pr_info("cryptd: max_cpu_qlen set to %d\n", max_cpu_qlen);
+	return 0;
+}
+
+static void cryptd_fini_queue(struct cryptd_queue *queue)
+{
+	int cpu;
+	struct cryptd_cpu_queue *cpu_queue;
+
+	for_each_possible_cpu(cpu) {
+		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
+		BUG_ON(cpu_queue->queue.qlen);
+	}
+	free_percpu(queue->cpu_queue);
+}
+
+static int cryptd_enqueue_request(struct cryptd_queue *queue,
+				  struct crypto_async_request *request)
+{
+	int err;
+	struct cryptd_cpu_queue *cpu_queue;
+	refcount_t *refcnt;
+
+	local_bh_disable();
+	local_lock_nested_bh(&queue->cpu_queue->bh_lock);
+	cpu_queue = this_cpu_ptr(queue->cpu_queue);
+	err = crypto_enqueue_request(&cpu_queue->queue, request);
+
+	refcnt = crypto_tfm_ctx(request->tfm);
+
+	if (err == -ENOSPC)
+		goto out;
+
+	queue_work_on(smp_processor_id(), cryptd_wq, &cpu_queue->work);
+
+	if (!refcount_read(refcnt))
+		goto out;
+
+	refcount_inc(refcnt);
+
+out:
+	local_unlock_nested_bh(&queue->cpu_queue->bh_lock);
+	local_bh_enable();
+
+	return err;
+}
+
+/* Called in workqueue context, do one real cryption work (via
+ * req->complete) and reschedule itself if there are more work to
+ * do. */
+static void cryptd_queue_worker(struct work_struct *work)
+{
+	struct cryptd_cpu_queue *cpu_queue;
+	struct crypto_async_request *req, *backlog;
+
+	cpu_queue = container_of(work, struct cryptd_cpu_queue, work);
+	/*
+	 * Only handle one request at a time to avoid hogging crypto workqueue.
+	 */
+	local_bh_disable();
+	__local_lock_nested_bh(&cpu_queue->bh_lock);
+	backlog = crypto_get_backlog(&cpu_queue->queue);
+	req = crypto_dequeue_request(&cpu_queue->queue);
+	__local_unlock_nested_bh(&cpu_queue->bh_lock);
+	local_bh_enable();
+
+	if (!req)
+		return;
+
+	if (backlog)
+		crypto_request_complete(backlog, -EINPROGRESS);
+	crypto_request_complete(req, 0);
+
+	if (cpu_queue->queue.qlen)
+		queue_work(cryptd_wq, &cpu_queue->work);
+}
+
+static inline struct cryptd_queue *cryptd_get_queue(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
+	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
+	return ictx->queue;
+}
+
+static void cryptd_type_and_mask(struct crypto_attr_type *algt,
+				 u32 *type, u32 *mask)
+{
+	/*
+	 * cryptd is allowed to wrap internal algorithms, but in that case the
+	 * resulting cryptd instance will be marked as internal as well.
+	 */
+	*type = algt->type & CRYPTO_ALG_INTERNAL;
+	*mask = algt->mask & CRYPTO_ALG_INTERNAL;
+
+	/* No point in cryptd wrapping an algorithm that's already async. */
+	*mask |= CRYPTO_ALG_ASYNC;
+
+	*mask |= crypto_algt_inherited_mask(algt);
+}
+
+static int cryptd_init_instance(struct crypto_instance *inst,
+				struct crypto_alg *alg)
+{
+	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+		     "cryptd(%s)",
+		     alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
+		return -ENAMETOOLONG;
+
+	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;
+
+	return 0;
+}
+
+static int cryptd_skcipher_setkey(struct crypto_skcipher *parent,
+				  const u8 *key, unsigned int keylen)
+{
+	struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(parent);
+	struct crypto_skcipher *child = ctx->child;
+
+	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+	crypto_skcipher_set_flags(child,
+				  crypto_skcipher_get_flags(parent) &
+				  CRYPTO_TFM_REQ_MASK);
+	return crypto_skcipher_setkey(child, key, keylen);
+}
+
+static struct skcipher_request *cryptd_skcipher_prepare(
+	struct skcipher_request *req, int err)
+{
+	struct cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->req;
+	struct cryptd_skcipher_ctx *ctx;
+	struct crypto_skcipher *child;
+
+	req->base.complete = subreq->base.complete;
+	req->base.data = subreq->base.data;
+
+	if (unlikely(err == -EINPROGRESS))
+		return NULL;
+
+	ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+	child = ctx->child;
+
+	skcipher_request_set_tfm(subreq, child);
+	skcipher_request_set_callback(subreq, CRYPTO_TFM_REQ_MAY_SLEEP,
+				      NULL, NULL);
+	skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
+				   req->iv);
+
+	return subreq;
+}
+
+static void cryptd_skcipher_complete(struct skcipher_request *req, int err,
+				     crypto_completion_t complete)
+{
+	struct cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_request *subreq = &rctx->req;
+	int refcnt = refcount_read(&ctx->refcnt);
+
+	local_bh_disable();
+	skcipher_request_complete(req, err);
+	local_bh_enable();
+
+	if (unlikely(err == -EINPROGRESS)) {
+		subreq->base.complete = req->base.complete;
+		subreq->base.data = req->base.data;
+		req->base.complete = complete;
+		req->base.data = req;
+	} else if (refcnt && refcount_dec_and_test(&ctx->refcnt))
+		crypto_free_skcipher(tfm);
+}
+
+static void cryptd_skcipher_encrypt(void *data, int err)
+{
+	struct skcipher_request *req = data;
+	struct skcipher_request *subreq;
+
+	subreq = cryptd_skcipher_prepare(req, err);
+	if (likely(subreq))
+		err = crypto_skcipher_encrypt(subreq);
+
+	cryptd_skcipher_complete(req, err, cryptd_skcipher_encrypt);
+}
+
+static void cryptd_skcipher_decrypt(void *data, int err)
+{
+	struct skcipher_request *req = data;
+	struct skcipher_request *subreq;
+
+	subreq = cryptd_skcipher_prepare(req, err);
+	if (likely(subreq))
+		err = crypto_skcipher_decrypt(subreq);
+
+	cryptd_skcipher_complete(req, err, cryptd_skcipher_decrypt);
+}
+
+static int cryptd_skcipher_enqueue(struct skcipher_request *req,
+				   crypto_completion_t compl)
+{
+	struct cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct skcipher_request *subreq = &rctx->req;
+	struct cryptd_queue *queue;
+
+	queue = cryptd_get_queue(crypto_skcipher_tfm(tfm));
+	subreq->base.complete = req->base.complete;
+	subreq->base.data = req->base.data;
+	req->base.complete = compl;
+	req->base.data = req;
+
+	return cryptd_enqueue_request(queue, &req->base);
+}
+
+static int cryptd_skcipher_encrypt_enqueue(struct skcipher_request *req)
+{
+	return cryptd_skcipher_enqueue(req, cryptd_skcipher_encrypt);
+}
+
+static int cryptd_skcipher_decrypt_enqueue(struct skcipher_request *req)
+{
+	return cryptd_skcipher_enqueue(req, cryptd_skcipher_decrypt);
+}
+
+static int cryptd_skcipher_init_tfm(struct crypto_skcipher *tfm)
+{
+	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+	struct skcipherd_instance_ctx *ictx = skcipher_instance_ctx(inst);
+	struct crypto_skcipher_spawn *spawn = &ictx->spawn;
+	struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_skcipher *cipher;
+
+	cipher = crypto_spawn_skcipher(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+	crypto_skcipher_set_reqsize(
+		tfm, sizeof(struct cryptd_skcipher_request_ctx) +
+		     crypto_skcipher_reqsize(cipher));
+	return 0;
+}
+
+static void cryptd_skcipher_exit_tfm(struct crypto_skcipher *tfm)
+{
+	struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	crypto_free_skcipher(ctx->child);
+}
+
+static void cryptd_skcipher_free(struct skcipher_instance *inst)
+{
+	struct skcipherd_instance_ctx *ctx = skcipher_instance_ctx(inst);
+
+	crypto_drop_skcipher(&ctx->spawn);
+	kfree(inst);
+}
+
+static int cryptd_create_skcipher(struct crypto_template *tmpl,
+				  struct rtattr **tb,
+				  struct crypto_attr_type *algt,
+				  struct cryptd_queue *queue)
+{
+	struct skcipherd_instance_ctx *ctx;
+	struct skcipher_instance *inst;
+	struct skcipher_alg_common *alg;
+	u32 type;
+	u32 mask;
+	int err;
+
+	cryptd_type_and_mask(algt, &type, &mask);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	ctx = skcipher_instance_ctx(inst);
+	ctx->queue = queue;
+
+	err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
+				   crypto_attr_alg_name(tb[1]), type, mask);
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_spawn_skcipher_alg_common(&ctx->spawn);
+	err = cryptd_init_instance(skcipher_crypto_instance(inst), &alg->base);
+	if (err)
+		goto err_free_inst;
+
+	inst->alg.base.cra_flags |= CRYPTO_ALG_ASYNC |
+		(alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
+	inst->alg.ivsize = alg->ivsize;
+	inst->alg.chunksize = alg->chunksize;
+	inst->alg.min_keysize = alg->min_keysize;
+	inst->alg.max_keysize = alg->max_keysize;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct cryptd_skcipher_ctx);
+
+	inst->alg.init = cryptd_skcipher_init_tfm;
+	inst->alg.exit = cryptd_skcipher_exit_tfm;
+
+	inst->alg.setkey = cryptd_skcipher_setkey;
+	inst->alg.encrypt = cryptd_skcipher_encrypt_enqueue;
+	inst->alg.decrypt = cryptd_skcipher_decrypt_enqueue;
+
+	inst->free = cryptd_skcipher_free;
+
+	err = skcipher_register_instance(tmpl, inst);
+	if (err) {
+err_free_inst:
+		cryptd_skcipher_free(inst);
+	}
+	return err;
+}
+
+static int cryptd_hash_init_tfm(struct crypto_ahash *tfm)
+{
+	struct ahash_instance *inst = ahash_alg_instance(tfm);
+	struct hashd_instance_ctx *ictx = ahash_instance_ctx(inst);
+	struct crypto_shash_spawn *spawn = &ictx->spawn;
+	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+	struct crypto_shash *hash;
+
+	hash = crypto_spawn_shash(spawn);
+	if (IS_ERR(hash))
+		return PTR_ERR(hash);
+
+	ctx->child = hash;
+	crypto_ahash_set_reqsize(tfm,
+				 sizeof(struct cryptd_hash_request_ctx) +
+				 crypto_shash_descsize(hash));
+	return 0;
+}
+
+static void cryptd_hash_exit_tfm(struct crypto_ahash *tfm)
+{
+	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+
+	crypto_free_shash(ctx->child);
+}
+
+static int cryptd_hash_setkey(struct crypto_ahash *parent,
+				   const u8 *key, unsigned int keylen)
+{
+	struct cryptd_hash_ctx *ctx   = crypto_ahash_ctx(parent);
+	struct crypto_shash *child = ctx->child;
+
+	crypto_shash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+	crypto_shash_set_flags(child, crypto_ahash_get_flags(parent) &
+				      CRYPTO_TFM_REQ_MASK);
+	return crypto_shash_setkey(child, key, keylen);
+}
+
+static int cryptd_hash_enqueue(struct ahash_request *req,
+				crypto_completion_t compl)
+{
+	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct cryptd_queue *queue =
+		cryptd_get_queue(crypto_ahash_tfm(tfm));
+
+	rctx->complete = req->base.complete;
+	rctx->data = req->base.data;
+	req->base.complete = compl;
+	req->base.data = req;
+
+	return cryptd_enqueue_request(queue, &req->base);
+}
+
+static struct shash_desc *cryptd_hash_prepare(struct ahash_request *req,
+					      int err)
+{
+	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
+
+	req->base.complete = rctx->complete;
+	req->base.data = rctx->data;
+
+	if (unlikely(err == -EINPROGRESS))
+		return NULL;
+
+	return &rctx->desc;
+}
+
+static void cryptd_hash_complete(struct ahash_request *req, int err,
+				 crypto_completion_t complete)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+	int refcnt = refcount_read(&ctx->refcnt);
+
+	local_bh_disable();
+	ahash_request_complete(req, err);
+	local_bh_enable();
+
+	if (err == -EINPROGRESS) {
+		req->base.complete = complete;
+		req->base.data = req;
+	} else if (refcnt && refcount_dec_and_test(&ctx->refcnt))
+		crypto_free_ahash(tfm);
+}
+
+static void cryptd_hash_init(void *data, int err)
+{
+	struct ahash_request *req = data;
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+	struct crypto_shash *child = ctx->child;
+	struct shash_desc *desc;
+
+	desc = cryptd_hash_prepare(req, err);
+	if (unlikely(!desc))
+		goto out;
+
+	desc->tfm = child;
+
+	err = crypto_shash_init(desc);
+
+out:
+	cryptd_hash_complete(req, err, cryptd_hash_init);
+}
+
+static int cryptd_hash_init_enqueue(struct ahash_request *req)
+{
+	return cryptd_hash_enqueue(req, cryptd_hash_init);
+}
+
+static void cryptd_hash_update(void *data, int err)
+{
+	struct ahash_request *req = data;
+	struct shash_desc *desc;
+
+	desc = cryptd_hash_prepare(req, err);
+	if (likely(desc))
+		err = shash_ahash_update(req, desc);
+
+	cryptd_hash_complete(req, err, cryptd_hash_update);
+}
+
+static int cryptd_hash_update_enqueue(struct ahash_request *req)
+{
+	return cryptd_hash_enqueue(req, cryptd_hash_update);
+}
+
+static void cryptd_hash_final(void *data, int err)
+{
+	struct ahash_request *req = data;
+	struct shash_desc *desc;
+
+	desc = cryptd_hash_prepare(req, err);
+	if (likely(desc))
+		err = crypto_shash_final(desc, req->result);
+
+	cryptd_hash_complete(req, err, cryptd_hash_final);
+}
+
+static int cryptd_hash_final_enqueue(struct ahash_request *req)
+{
+	return cryptd_hash_enqueue(req, cryptd_hash_final);
+}
+
+static void cryptd_hash_finup(void *data, int err)
+{
+	struct ahash_request *req = data;
+	struct shash_desc *desc;
+
+	desc = cryptd_hash_prepare(req, err);
+	if (likely(desc))
+		err = shash_ahash_finup(req, desc);
+
+	cryptd_hash_complete(req, err, cryptd_hash_finup);
+}
+
+static int cryptd_hash_finup_enqueue(struct ahash_request *req)
+{
+	return cryptd_hash_enqueue(req, cryptd_hash_finup);
+}
+
+static void cryptd_hash_digest(void *data, int err)
+{
+	struct ahash_request *req = data;
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+	struct crypto_shash *child = ctx->child;
+	struct shash_desc *desc;
+
+	desc = cryptd_hash_prepare(req, err);
+	if (unlikely(!desc))
+		goto out;
+
+	desc->tfm = child;
+
+	err = shash_ahash_digest(req, desc);
+
+out:
+	cryptd_hash_complete(req, err, cryptd_hash_digest);
+}
+
+static int cryptd_hash_digest_enqueue(struct ahash_request *req)
+{
+	return cryptd_hash_enqueue(req, cryptd_hash_digest);
+}
+
+static int cryptd_hash_export(struct ahash_request *req, void *out)
+{
+	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
+
+	return crypto_shash_export(&rctx->desc, out);
+}
+
+static int cryptd_hash_import(struct ahash_request *req, const void *in)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
+	struct shash_desc *desc = &rctx->desc;
+
+	desc->tfm = ctx->child;
+
+	return crypto_shash_import(desc, in);
+}
+
+static void cryptd_hash_free(struct ahash_instance *inst)
+{
+	struct hashd_instance_ctx *ctx = ahash_instance_ctx(inst);
+
+	crypto_drop_shash(&ctx->spawn);
+	kfree(inst);
+}
+
+static int cryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
+			      struct crypto_attr_type *algt,
+			      struct cryptd_queue *queue)
+{
+	struct hashd_instance_ctx *ctx;
+	struct ahash_instance *inst;
+	struct shash_alg *alg;
+	u32 type;
+	u32 mask;
+	int err;
+
+	cryptd_type_and_mask(algt, &type, &mask);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	ctx = ahash_instance_ctx(inst);
+	ctx->queue = queue;
+
+	err = crypto_grab_shash(&ctx->spawn, ahash_crypto_instance(inst),
+				crypto_attr_alg_name(tb[1]), type, mask);
+	if (err)
+		goto err_free_inst;
+	alg = crypto_spawn_shash_alg(&ctx->spawn);
+
+	err = cryptd_init_instance(ahash_crypto_instance(inst), &alg->base);
+	if (err)
+		goto err_free_inst;
+
+	inst->alg.halg.base.cra_flags |= CRYPTO_ALG_ASYNC |
+		(alg->base.cra_flags & (CRYPTO_ALG_INTERNAL|
+					CRYPTO_ALG_OPTIONAL_KEY));
+	inst->alg.halg.digestsize = alg->digestsize;
+	inst->alg.halg.statesize = alg->statesize;
+	inst->alg.halg.base.cra_ctxsize = sizeof(struct cryptd_hash_ctx);
+
+	inst->alg.init_tfm = cryptd_hash_init_tfm;
+	inst->alg.exit_tfm = cryptd_hash_exit_tfm;
+
+	inst->alg.init   = cryptd_hash_init_enqueue;
+	inst->alg.update = cryptd_hash_update_enqueue;
+	inst->alg.final  = cryptd_hash_final_enqueue;
+	inst->alg.finup  = cryptd_hash_finup_enqueue;
+	inst->alg.export = cryptd_hash_export;
+	inst->alg.import = cryptd_hash_import;
+	if (crypto_shash_alg_has_setkey(alg))
+		inst->alg.setkey = cryptd_hash_setkey;
+	inst->alg.digest = cryptd_hash_digest_enqueue;
+
+	inst->free = cryptd_hash_free;
+
+	err = ahash_register_instance(tmpl, inst);
+	if (err) {
+err_free_inst:
+		cryptd_hash_free(inst);
+	}
+	return err;
+}
+
+static int cryptd_aead_setkey(struct crypto_aead *parent,
+			      const u8 *key, unsigned int keylen)
+{
+	struct cryptd_aead_ctx *ctx = crypto_aead_ctx(parent);
+	struct crypto_aead *child = ctx->child;
+
+	return crypto_aead_setkey(child, key, keylen);
+}
+
+static int cryptd_aead_setauthsize(struct crypto_aead *parent,
+				   unsigned int authsize)
+{
+	struct cryptd_aead_ctx *ctx = crypto_aead_ctx(parent);
+	struct crypto_aead *child = ctx->child;
+
+	return crypto_aead_setauthsize(child, authsize);
+}
+
+static void cryptd_aead_crypt(struct aead_request *req,
+			      struct crypto_aead *child, int err,
+			      int (*crypt)(struct aead_request *req),
+			      crypto_completion_t compl)
+{
+	struct cryptd_aead_request_ctx *rctx;
+	struct aead_request *subreq;
+	struct cryptd_aead_ctx *ctx;
+	struct crypto_aead *tfm;
+	int refcnt;
+
+	rctx = aead_request_ctx(req);
+	subreq = &rctx->req;
+	req->base.complete = subreq->base.complete;
+	req->base.data = subreq->base.data;
+
+	tfm = crypto_aead_reqtfm(req);
+
+	if (unlikely(err == -EINPROGRESS))
+		goto out;
+
+	aead_request_set_tfm(subreq, child);
+	aead_request_set_callback(subreq, CRYPTO_TFM_REQ_MAY_SLEEP,
+				  NULL, NULL);
+	aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
+			       req->iv);
+	aead_request_set_ad(subreq, req->assoclen);
+
+	err = crypt(subreq);
+
+out:
+	ctx = crypto_aead_ctx(tfm);
+	refcnt = refcount_read(&ctx->refcnt);
+
+	local_bh_disable();
+	aead_request_complete(req, err);
+	local_bh_enable();
+
+	if (err == -EINPROGRESS) {
+		subreq->base.complete = req->base.complete;
+		subreq->base.data = req->base.data;
+		req->base.complete = compl;
+		req->base.data = req;
+	} else if (refcnt && refcount_dec_and_test(&ctx->refcnt))
+		crypto_free_aead(tfm);
+}
+
+static void cryptd_aead_encrypt(void *data, int err)
+{
+	struct aead_request *req = data;
+	struct cryptd_aead_ctx *ctx;
+	struct crypto_aead *child;
+
+	ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
+	child = ctx->child;
+	cryptd_aead_crypt(req, child, err, crypto_aead_alg(child)->encrypt,
+			  cryptd_aead_encrypt);
+}
+
+static void cryptd_aead_decrypt(void *data, int err)
+{
+	struct aead_request *req = data;
+	struct cryptd_aead_ctx *ctx;
+	struct crypto_aead *child;
+
+	ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
+	child = ctx->child;
+	cryptd_aead_crypt(req, child, err, crypto_aead_alg(child)->decrypt,
+			  cryptd_aead_decrypt);
+}
+
+static int cryptd_aead_enqueue(struct aead_request *req,
+				    crypto_completion_t compl)
+{
+	struct cryptd_aead_request_ctx *rctx = aead_request_ctx(req);
+	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
+	struct cryptd_queue *queue = cryptd_get_queue(crypto_aead_tfm(tfm));
+	struct aead_request *subreq = &rctx->req;
+
+	subreq->base.complete = req->base.complete;
+	subreq->base.data = req->base.data;
+	req->base.complete = compl;
+	req->base.data = req;
+	return cryptd_enqueue_request(queue, &req->base);
+}
+
+static int cryptd_aead_encrypt_enqueue(struct aead_request *req)
+{
+	return cryptd_aead_enqueue(req, cryptd_aead_encrypt );
+}
+
+static int cryptd_aead_decrypt_enqueue(struct aead_request *req)
+{
+	return cryptd_aead_enqueue(req, cryptd_aead_decrypt );
+}
+
+static int cryptd_aead_init_tfm(struct crypto_aead *tfm)
+{
+	struct aead_instance *inst = aead_alg_instance(tfm);
+	struct aead_instance_ctx *ictx = aead_instance_ctx(inst);
+	struct crypto_aead_spawn *spawn = &ictx->aead_spawn;
+	struct cryptd_aead_ctx *ctx = crypto_aead_ctx(tfm);
+	struct crypto_aead *cipher;
+
+	cipher = crypto_spawn_aead(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+	crypto_aead_set_reqsize(
+		tfm, sizeof(struct cryptd_aead_request_ctx) +
+		     crypto_aead_reqsize(cipher));
+	return 0;
+}
+
+static void cryptd_aead_exit_tfm(struct crypto_aead *tfm)
+{
+	struct cryptd_aead_ctx *ctx = crypto_aead_ctx(tfm);
+	crypto_free_aead(ctx->child);
+}
+
+static void cryptd_aead_free(struct aead_instance *inst)
+{
+	struct aead_instance_ctx *ctx = aead_instance_ctx(inst);
+
+	crypto_drop_aead(&ctx->aead_spawn);
+	kfree(inst);
+}
+
+static int cryptd_create_aead(struct crypto_template *tmpl,
+		              struct rtattr **tb,
+			      struct crypto_attr_type *algt,
+			      struct cryptd_queue *queue)
+{
+	struct aead_instance_ctx *ctx;
+	struct aead_instance *inst;
+	struct aead_alg *alg;
+	u32 type;
+	u32 mask;
+	int err;
+
+	cryptd_type_and_mask(algt, &type, &mask);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	ctx = aead_instance_ctx(inst);
+	ctx->queue = queue;
+
+	err = crypto_grab_aead(&ctx->aead_spawn, aead_crypto_instance(inst),
+			       crypto_attr_alg_name(tb[1]), type, mask);
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_spawn_aead_alg(&ctx->aead_spawn);
+	err = cryptd_init_instance(aead_crypto_instance(inst), &alg->base);
+	if (err)
+		goto err_free_inst;
+
+	inst->alg.base.cra_flags |= CRYPTO_ALG_ASYNC |
+		(alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
+	inst->alg.base.cra_ctxsize = sizeof(struct cryptd_aead_ctx);
+
+	inst->alg.ivsize = crypto_aead_alg_ivsize(alg);
+	inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);
+
+	inst->alg.init = cryptd_aead_init_tfm;
+	inst->alg.exit = cryptd_aead_exit_tfm;
+	inst->alg.setkey = cryptd_aead_setkey;
+	inst->alg.setauthsize = cryptd_aead_setauthsize;
+	inst->alg.encrypt = cryptd_aead_encrypt_enqueue;
+	inst->alg.decrypt = cryptd_aead_decrypt_enqueue;
+
+	inst->free = cryptd_aead_free;
+
+	err = aead_register_instance(tmpl, inst);
+	if (err) {
+err_free_inst:
+		cryptd_aead_free(inst);
+	}
+	return err;
+}
+
+static struct cryptd_queue queue;
+
+static int cryptd_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct crypto_attr_type *algt;
+
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return PTR_ERR(algt);
+
+	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
+	case CRYPTO_ALG_TYPE_LSKCIPHER:
+		return cryptd_create_skcipher(tmpl, tb, algt, &queue);
+	case CRYPTO_ALG_TYPE_HASH:
+		return cryptd_create_hash(tmpl, tb, algt, &queue);
+	case CRYPTO_ALG_TYPE_AEAD:
+		return cryptd_create_aead(tmpl, tb, algt, &queue);
+	}
+
+	return -EINVAL;
+}
+
+static struct crypto_template cryptd_tmpl = {
+	.name = "cryptd",
+	.create = cryptd_create,
+	.module = THIS_MODULE,
+};
+
+struct cryptd_aead *cryptd_alloc_aead(const char *alg_name,
+						  u32 type, u32 mask)
+{
+	char cryptd_alg_name[CRYPTO_MAX_ALG_NAME];
+	struct cryptd_aead_ctx *ctx;
+	struct crypto_aead *tfm;
+
+	if (snprintf(cryptd_alg_name, CRYPTO_MAX_ALG_NAME,
+		     "cryptd(%s)", alg_name) >= CRYPTO_MAX_ALG_NAME)
+		return ERR_PTR(-EINVAL);
+	tfm = crypto_alloc_aead(cryptd_alg_name, type, mask);
+	if (IS_ERR(tfm))
+		return ERR_CAST(tfm);
+	if (tfm->base.__crt_alg->cra_module != THIS_MODULE) {
+		crypto_free_aead(tfm);
+		return ERR_PTR(-EINVAL);
+	}
+
+	ctx = crypto_aead_ctx(tfm);
+	refcount_set(&ctx->refcnt, 1);
+
+	return __cryptd_aead_cast(tfm);
+}
+EXPORT_SYMBOL_GPL(cryptd_alloc_aead);
+
+struct crypto_aead *cryptd_aead_child(struct cryptd_aead *tfm)
+{
+	struct cryptd_aead_ctx *ctx;
+	ctx = crypto_aead_ctx(&tfm->base);
+	return ctx->child;
+}
+EXPORT_SYMBOL_GPL(cryptd_aead_child);
+
+bool cryptd_aead_queued(struct cryptd_aead *tfm)
+{
+	struct cryptd_aead_ctx *ctx = crypto_aead_ctx(&tfm->base);
+
+	return refcount_read(&ctx->refcnt) - 1;
+}
+EXPORT_SYMBOL_GPL(cryptd_aead_queued);
+
+void cryptd_free_aead(struct cryptd_aead *tfm)
+{
+	struct cryptd_aead_ctx *ctx = crypto_aead_ctx(&tfm->base);
+
+	if (refcount_dec_and_test(&ctx->refcnt))
+		crypto_free_aead(&tfm->base);
+}
+EXPORT_SYMBOL_GPL(cryptd_free_aead);
+
+static int __init cryptd_init(void)
+{
+	int err;
+
+	cryptd_wq = alloc_workqueue("cryptd",
+				    WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE | WQ_PERCPU,
+				    1);
+	if (!cryptd_wq)
+		return -ENOMEM;
+
+	err = cryptd_init_queue(&queue, cryptd_max_cpu_qlen);
+	if (err)
+		goto err_destroy_wq;
+
+	err = crypto_register_template(&cryptd_tmpl);
+	if (err)
+		goto err_fini_queue;
+
+	return 0;
+
+err_fini_queue:
+	cryptd_fini_queue(&queue);
+err_destroy_wq:
+	destroy_workqueue(cryptd_wq);
+	return err;
+}
+
+static void __exit cryptd_exit(void)
+{
+	destroy_workqueue(cryptd_wq);
+	cryptd_fini_queue(&queue);
+	crypto_unregister_template(&cryptd_tmpl);
+}
+
+module_init(cryptd_init);
+module_exit(cryptd_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Software async crypto daemon");
+MODULE_ALIAS_CRYPTO("cryptd");