text: /*
   * Asynchronous Cryptographic Hash operations.
   *
   * This is the asynchronous version of hash.c with notification of
   * completion via a callback.
   *
   * Copyright (c) 2008 Loc Ho <lho@amcc.com>
   *
   * 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/hash.h>
  #include <crypto/scatterwalk.h>
  #include <linux/bug.h>
  #include <linux/err.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/seq_file.h>
  #include <linux/cryptouser.h>
  #include <net/netlink.h>
  
  #include "internal.h"
  
  struct ahash_request_priv {
  	crypto_completion_t complete;
  	void *data;
  	u8 *result;
  	void *ubuf[] CRYPTO_MINALIGN_ATTR;
  };
  
  static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  {
  	return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  			    halg);
  }
  
  static int hash_walk_next(struct crypto_hash_walk *walk)
  {
  	unsigned int alignmask = walk->alignmask;
  	unsigned int offset = walk->offset;
  	unsigned int nbytes = min(walk->entrylen,
  				  ((unsigned int)(PAGE_SIZE)) - offset);
  
  	if (walk->flags & CRYPTO_ALG_ASYNC)
  		walk->data = kmap(walk->pg);
  	else
  		walk->data = kmap_atomic(walk->pg);
  	walk->data += offset;
  
  	if (offset & alignmask) {
  		unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  
  		if (nbytes > unaligned)
  			nbytes = unaligned;
  	}
  
  	walk->entrylen -= nbytes;
  	return nbytes;
  }
  
  static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  {
  	struct scatterlist *sg;
  
  	sg = walk->sg;
  	walk->pg = sg_page(sg);
  	walk->offset = sg->offset;
  	walk->entrylen = sg->length;
  
  	if (walk->entrylen > walk->total)
  		walk->entrylen = walk->total;
  	walk->total -= walk->entrylen;
  
  	return hash_walk_next(walk);
  }
  
  int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  {
  	unsigned int alignmask = walk->alignmask;
  	unsigned int nbytes = walk->entrylen;
  
  	walk->data -= walk->offset;
  
  	if (nbytes && walk->offset & alignmask && !err) {
  		walk->offset = ALIGN(walk->offset, alignmask + 1);
  		walk->data += walk->offset;
  
  		nbytes = min(nbytes,
  			     ((unsigned int)(PAGE_SIZE)) - walk->offset);
  		walk->entrylen -= nbytes;
  
  		return nbytes;
  	}
  
  	if (walk->flags & CRYPTO_ALG_ASYNC)
  		kunmap(walk->pg);
  	else {
  		kunmap_atomic(walk->data);
  		/*
  		 * The may sleep test only makes sense for sync users.
  		 * Async users don't need to sleep here anyway.
  		 */
  		crypto_yield(walk->flags);
  	}
  
  	if (err)
  		return err;
  
  	if (nbytes) {
  		walk->offset = 0;
  		walk->pg++;
  		return hash_walk_next(walk);
  	}
  
  	if (!walk->total)
  		return 0;
  
  	walk->sg = sg_next(walk->sg);
  
  	return hash_walk_new_entry(walk);
  }
  EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
  
  int crypto_hash_walk_first(struct ahash_request *req,
  			   struct crypto_hash_walk *walk)
  {
  	walk->total = req->nbytes;
  
  	if (!walk->total) {
  		walk->entrylen = 0;
  		return 0;
  	}
  
  	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
  	walk->sg = req->src;
  	walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
  
  	return hash_walk_new_entry(walk);
  }
  EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
  
  int crypto_ahash_walk_first(struct ahash_request *req,
  			    struct crypto_hash_walk *walk)
  {
  	walk->total = req->nbytes;
  
  	if (!walk->total) {
  		walk->entrylen = 0;
  		return 0;
  	}
  
  	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
  	walk->sg = req->src;
  	walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
  	walk->flags |= CRYPTO_ALG_ASYNC;
  
  	BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
  
  	return hash_walk_new_entry(walk);
  }
  EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
  
  int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
  				  struct crypto_hash_walk *walk,
  				  struct scatterlist *sg, unsigned int len)
  {
  	walk->total = len;
  
  	if (!walk->total) {
  		walk->entrylen = 0;
  		return 0;
  	}
  
  	walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
  	walk->sg = sg;
  	walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
  
  	return hash_walk_new_entry(walk);
  }
  
  static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
  				unsigned int keylen)
  {
  	unsigned long alignmask = crypto_ahash_alignmask(tfm);
  	int ret;
  	u8 *buffer, *alignbuffer;
  	unsigned long absize;
  
  	absize = keylen + alignmask;
  	buffer = kmalloc(absize, GFP_KERNEL);
  	if (!buffer)
  		return -ENOMEM;
  
  	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  	memcpy(alignbuffer, key, keylen);
  	ret = tfm->setkey(tfm, alignbuffer, keylen);
  	kzfree(buffer);
  	return ret;
  }
  
  int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
  			unsigned int keylen)
  {
  	unsigned long alignmask = crypto_ahash_alignmask(tfm);
  
  	if ((unsigned long)key & alignmask)
  		return ahash_setkey_unaligned(tfm, key, keylen);
  
  	return tfm->setkey(tfm, key, keylen);
  }
  EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
  
  static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
  			  unsigned int keylen)
  {
  	return -ENOSYS;
  }
  
  static inline unsigned int ahash_align_buffer_size(unsigned len,
  						   unsigned long mask)
  {
  	return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
  }
  
  static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
  {
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	unsigned long alignmask = crypto_ahash_alignmask(tfm);
  	unsigned int ds = crypto_ahash_digestsize(tfm);
  	struct ahash_request_priv *priv;
  
  	priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
  		       (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
  		       GFP_KERNEL : GFP_ATOMIC);
  	if (!priv)
  		return -ENOMEM;
  
  	/*
  	 * WARNING: Voodoo programming below!
  	 *
  	 * The code below is obscure and hard to understand, thus explanation
  	 * is necessary. See include/crypto/hash.h and include/linux/crypto.h
  	 * to understand the layout of structures used here!
  	 *
  	 * The code here will replace portions of the ORIGINAL request with
  	 * pointers to new code and buffers so the hashing operation can store
  	 * the result in aligned buffer. We will call the modified request
  	 * an ADJUSTED request.
  	 *
  	 * The newly mangled request will look as such:
  	 *
  	 * req {
  	 *   .result        = ADJUSTED[new aligned buffer]
  	 *   .base.complete = ADJUSTED[pointer to completion function]
  	 *   .base.data     = ADJUSTED[*req (pointer to self)]
  	 *   .priv          = ADJUSTED[new priv] {
  	 *           .result   = ORIGINAL(result)
  	 *           .complete = ORIGINAL(base.complete)
  	 *           .data     = ORIGINAL(base.data)
  	 *   }
  	 */
  
  	priv->result = req->result;
  	priv->complete = req->base.complete;
  	priv->data = req->base.data;
  	/*
  	 * WARNING: We do not backup req->priv here! The req->priv
  	 *          is for internal use of the Crypto API and the
  	 *          user must _NOT_ _EVER_ depend on it's content!
  	 */
  
  	req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
  	req->base.complete = cplt;
  	req->base.data = req;
  	req->priv = priv;
  
  	return 0;
  }
  
  static void ahash_restore_req(struct ahash_request *req)
  {
  	struct ahash_request_priv *priv = req->priv;
  
  	/* Restore the original crypto request. */
  	req->result = priv->result;
  	req->base.complete = priv->complete;
  	req->base.data = priv->data;
  	req->priv = NULL;
  
  	/* Free the req->priv.priv from the ADJUSTED request. */
  	kzfree(priv);
  }
  
  static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
  {
  	struct ahash_request_priv *priv = req->priv;
  
  	if (err == -EINPROGRESS)
  		return;
  
  	if (!err)
  		memcpy(priv->result, req->result,
  		       crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
  
  	ahash_restore_req(req);
  }
  
  static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
  {
  	struct ahash_request *areq = req->data;
  
  	/*
  	 * Restore the original request, see ahash_op_unaligned() for what
  	 * goes where.
  	 *
  	 * The "struct ahash_request *req" here is in fact the "req.base"
  	 * from the ADJUSTED request from ahash_op_unaligned(), thus as it
  	 * is a pointer to self, it is also the ADJUSTED "req" .
  	 */
  
  	/* First copy req->result into req->priv.result */
  	ahash_op_unaligned_finish(areq, err);
  
  	/* Complete the ORIGINAL request. */
  	areq->base.complete(&areq->base, err);
  }
  
  static int ahash_op_unaligned(struct ahash_request *req,
  			      int (*op)(struct ahash_request *))
  {
  	int err;
  
  	err = ahash_save_req(req, ahash_op_unaligned_done);
  	if (err)
  		return err;
  
  	err = op(req);
  	ahash_op_unaligned_finish(req, err);
  
  	return err;
  }
  
  static int crypto_ahash_op(struct ahash_request *req,
  			   int (*op)(struct ahash_request *))
  {
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	unsigned long alignmask = crypto_ahash_alignmask(tfm);
  
  	if ((unsigned long)req->result & alignmask)
  		return ahash_op_unaligned(req, op);
  
  	return op(req);
  }
  
  int crypto_ahash_final(struct ahash_request *req)
  {
  	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
  }
  EXPORT_SYMBOL_GPL(crypto_ahash_final);
  
  int crypto_ahash_finup(struct ahash_request *req)
  {
  	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
  }
  EXPORT_SYMBOL_GPL(crypto_ahash_finup);
  
  int crypto_ahash_digest(struct ahash_request *req)
  {
  	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
  }
  EXPORT_SYMBOL_GPL(crypto_ahash_digest);
  
  static void ahash_def_finup_finish2(struct ahash_request *req, int err)
  {
  	struct ahash_request_priv *priv = req->priv;
  
  	if (err == -EINPROGRESS)
  		return;
  
  	if (!err)
  		memcpy(priv->result, req->result,
  		       crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
  
  	ahash_restore_req(req);
  }
  
  static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
  {
  	struct ahash_request *areq = req->data;
  
  	ahash_def_finup_finish2(areq, err);
  
  	areq->base.complete(&areq->base, err);
  }
  
  static int ahash_def_finup_finish1(struct ahash_request *req, int err)
  {
  	if (err)
  		goto out;
  
  	req->base.complete = ahash_def_finup_done2;
  	req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
  	err = crypto_ahash_reqtfm(req)->final(req);
  
  out:
  	ahash_def_finup_finish2(req, err);
  	return err;
  }
  
  static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
  {
  	struct ahash_request *areq = req->data;
  
  	err = ahash_def_finup_finish1(areq, err);
  
  	areq->base.complete(&areq->base, err);
  }
  
  static int ahash_def_finup(struct ahash_request *req)
  {
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	int err;
  
  	err = ahash_save_req(req, ahash_def_finup_done1);
  	if (err)
  		return err;
  
  	err = tfm->update(req);
  	return ahash_def_finup_finish1(req, err);
  }
  
  static int ahash_no_export(struct ahash_request *req, void *out)
  {
  	return -ENOSYS;
  }
  
  static int ahash_no_import(struct ahash_request *req, const void *in)
  {
  	return -ENOSYS;
  }
  
  static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
  	struct ahash_alg *alg = crypto_ahash_alg(hash);
  
  	hash->setkey = ahash_nosetkey;
  	hash->has_setkey = false;
  	hash->export = ahash_no_export;
  	hash->import = ahash_no_import;
  
  	if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
  		return crypto_init_shash_ops_async(tfm);
  
  	hash->init = alg->init;
  	hash->update = alg->update;
  	hash->final = alg->final;
  	hash->finup = alg->finup ?: ahash_def_finup;
  	hash->digest = alg->digest;
  
  	if (alg->setkey) {
  		hash->setkey = alg->setkey;
  		hash->has_setkey = true;
  	}
  	if (alg->export)
  		hash->export = alg->export;
  	if (alg->import)
  		hash->import = alg->import;
  
  	return 0;
  }
  
  static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
  {
  	if (alg->cra_type == &crypto_ahash_type)
  		return alg->cra_ctxsize;
  
  	return sizeof(struct crypto_shash *);
  }
  
  #ifdef CONFIG_NET
  static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	struct crypto_report_hash rhash;
  
  	strncpy(rhash.type, "ahash", sizeof(rhash.type));
  
  	rhash.blocksize = alg->cra_blocksize;
  	rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
  
  	if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
  		    sizeof(struct crypto_report_hash), &rhash))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }
  #else
  static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	return -ENOSYS;
  }
  #endif
  
  static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
  	__attribute__ ((unused));
  static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	seq_printf(m, "type         : ahash\n");
  	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
  					     "yes" : "no");
  	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
  	seq_printf(m, "digestsize   : %u\n",
  		   __crypto_hash_alg_common(alg)->digestsize);
  }
  
  const struct crypto_type crypto_ahash_type = {
  	.extsize = crypto_ahash_extsize,
  	.init_tfm = crypto_ahash_init_tfm,
  #ifdef CONFIG_PROC_FS
  	.show = crypto_ahash_show,
  #endif
  	.report = crypto_ahash_report,
  	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
  	.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
  	.type = CRYPTO_ALG_TYPE_AHASH,
  	.tfmsize = offsetof(struct crypto_ahash, base),
  };
  EXPORT_SYMBOL_GPL(crypto_ahash_type);
  
  struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
  					u32 mask)
  {
  	return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
  }
  EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
  
  static int ahash_prepare_alg(struct ahash_alg *alg)
  {
  	struct crypto_alg *base = &alg->halg.base;
  
  	if (alg->halg.digestsize > PAGE_SIZE / 8 ||
  	    alg->halg.statesize > PAGE_SIZE / 8 ||
  	    alg->halg.statesize == 0)
  		return -EINVAL;
  
  	base->cra_type = &crypto_ahash_type;
  	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
  	base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
  
  	return 0;
  }
  
  int crypto_register_ahash(struct ahash_alg *alg)
  {
  	struct crypto_alg *base = &alg->halg.base;
  	int err;
  
  	err = ahash_prepare_alg(alg);
  	if (err)
  		return err;
  
  	return crypto_register_alg(base);
  }
  EXPORT_SYMBOL_GPL(crypto_register_ahash);
  
  int crypto_unregister_ahash(struct ahash_alg *alg)
  {
  	return crypto_unregister_alg(&alg->halg.base);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
  
  int ahash_register_instance(struct crypto_template *tmpl,
  			    struct ahash_instance *inst)
  {
  	int err;
  
  	err = ahash_prepare_alg(&inst->alg);
  	if (err)
  		return err;
  
  	return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
  }
  EXPORT_SYMBOL_GPL(ahash_register_instance);
  
  void ahash_free_instance(struct crypto_instance *inst)
  {
  	crypto_drop_spawn(crypto_instance_ctx(inst));
  	kfree(ahash_instance(inst));
  }
  EXPORT_SYMBOL_GPL(ahash_free_instance);
  
  int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
  			    struct hash_alg_common *alg,
  			    struct crypto_instance *inst)
  {
  	return crypto_init_spawn2(&spawn->base, &alg->base, inst,
  				  &crypto_ahash_type);
  }
  EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
  
  struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
  {
  	struct crypto_alg *alg;
  
  	alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
  	return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
  }
  EXPORT_SYMBOL_GPL(ahash_attr_alg);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
  