/*
   * Symmetric key cipher operations.
   *
   * Generic encrypt/decrypt wrapper for ciphers, handles operations across
   * multiple page boundaries by using temporary blocks.  In user context,
   * the kernel is given a chance to schedule us once per page.
   *
   * Copyright (c) 2015 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/aead.h>

  #include <crypto/internal/skcipher.h>

  #include <crypto/scatterwalk.h>

  #include <linux/bug.h>

  #include <linux/cryptouser.h>

  #include <linux/compiler.h>

  #include <linux/list.h>

  #include <linux/module.h>

  #include <linux/rtnetlink.h>
  #include <linux/seq_file.h>
  #include <net/netlink.h>

  
  #include "internal.h"

  enum {
  	SKCIPHER_WALK_PHYS = 1 << 0,
  	SKCIPHER_WALK_SLOW = 1 << 1,
  	SKCIPHER_WALK_COPY = 1 << 2,
  	SKCIPHER_WALK_DIFF = 1 << 3,
  	SKCIPHER_WALK_SLEEP = 1 << 4,
  };
  
  struct skcipher_walk_buffer {
  	struct list_head entry;
  	struct scatter_walk dst;
  	unsigned int len;
  	u8 *data;
  	u8 buffer[];
  };
  
  static int skcipher_walk_next(struct skcipher_walk *walk);
  
  static inline void skcipher_unmap(struct scatter_walk *walk, void *vaddr)
  {
  	if (PageHighMem(scatterwalk_page(walk)))
  		kunmap_atomic(vaddr);
  }
  
  static inline void *skcipher_map(struct scatter_walk *walk)
  {
  	struct page *page = scatterwalk_page(walk);
  
  	return (PageHighMem(page) ? kmap_atomic(page) : page_address(page)) +
  	       offset_in_page(walk->offset);
  }
  
  static inline void skcipher_map_src(struct skcipher_walk *walk)
  {
  	walk->src.virt.addr = skcipher_map(&walk->in);
  }
  
  static inline void skcipher_map_dst(struct skcipher_walk *walk)
  {
  	walk->dst.virt.addr = skcipher_map(&walk->out);
  }
  
  static inline void skcipher_unmap_src(struct skcipher_walk *walk)
  {
  	skcipher_unmap(&walk->in, walk->src.virt.addr);
  }
  
  static inline void skcipher_unmap_dst(struct skcipher_walk *walk)
  {
  	skcipher_unmap(&walk->out, walk->dst.virt.addr);
  }
  
  static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk)
  {
  	return walk->flags & SKCIPHER_WALK_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
  }
  
  /* Get a spot of the specified length that does not straddle a page.
   * The caller needs to ensure that there is enough space for this operation.
   */
  static inline u8 *skcipher_get_spot(u8 *start, unsigned int len)
  {
  	u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  
  	return max(start, end_page);
  }

  static void skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize)

  {
  	u8 *addr;
  
  	addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
  	addr = skcipher_get_spot(addr, bsize);
  	scatterwalk_copychunks(addr, &walk->out, bsize,
  			       (walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1);

  }
  
  int skcipher_walk_done(struct skcipher_walk *walk, int err)
  {

  	unsigned int n; /* bytes processed */
  	bool more;
  
  	if (unlikely(err < 0))
  		goto finish;
  
  	n = walk->nbytes - err;
  	walk->total -= n;
  	more = (walk->total != 0);
  
  	if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS |
  				    SKCIPHER_WALK_SLOW |
  				    SKCIPHER_WALK_COPY |
  				    SKCIPHER_WALK_DIFF)))) {

  unmap_src:
  		skcipher_unmap_src(walk);
  	} else if (walk->flags & SKCIPHER_WALK_DIFF) {
  		skcipher_unmap_dst(walk);
  		goto unmap_src;
  	} else if (walk->flags & SKCIPHER_WALK_COPY) {
  		skcipher_map_dst(walk);
  		memcpy(walk->dst.virt.addr, walk->page, n);
  		skcipher_unmap_dst(walk);
  	} else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) {
  		if (WARN_ON(err)) {

  			/* unexpected case; didn't process all bytes */

  			err = -EINVAL;

  			goto finish;
  		}
  		skcipher_done_slow(walk, n);
  		goto already_advanced;

  	}

  	scatterwalk_advance(&walk->in, n);
  	scatterwalk_advance(&walk->out, n);

  already_advanced:
  	scatterwalk_done(&walk->in, 0, more);
  	scatterwalk_done(&walk->out, 1, more);

  	if (more) {

  		crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ?
  			     CRYPTO_TFM_REQ_MAY_SLEEP : 0);
  		return skcipher_walk_next(walk);
  	}

  	err = 0;
  finish:
  	walk->nbytes = 0;

  
  	/* Short-circuit for the common/fast path. */
  	if (!((unsigned long)walk->buffer | (unsigned long)walk->page))
  		goto out;
  
  	if (walk->flags & SKCIPHER_WALK_PHYS)
  		goto out;
  
  	if (walk->iv != walk->oiv)
  		memcpy(walk->oiv, walk->iv, walk->ivsize);
  	if (walk->buffer != walk->page)
  		kfree(walk->buffer);
  	if (walk->page)
  		free_page((unsigned long)walk->page);
  
  out:
  	return err;
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_done);
  
  void skcipher_walk_complete(struct skcipher_walk *walk, int err)
  {
  	struct skcipher_walk_buffer *p, *tmp;
  
  	list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
  		u8 *data;
  
  		if (err)
  			goto done;
  
  		data = p->data;
  		if (!data) {
  			data = PTR_ALIGN(&p->buffer[0], walk->alignmask + 1);

  			data = skcipher_get_spot(data, walk->stride);

  		}
  
  		scatterwalk_copychunks(data, &p->dst, p->len, 1);

  		if (offset_in_page(p->data) + p->len + walk->stride >

  		    PAGE_SIZE)
  			free_page((unsigned long)p->data);
  
  done:
  		list_del(&p->entry);
  		kfree(p);
  	}
  
  	if (!err && walk->iv != walk->oiv)
  		memcpy(walk->oiv, walk->iv, walk->ivsize);
  	if (walk->buffer != walk->page)
  		kfree(walk->buffer);
  	if (walk->page)
  		free_page((unsigned long)walk->page);
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_complete);
  
  static void skcipher_queue_write(struct skcipher_walk *walk,
  				 struct skcipher_walk_buffer *p)
  {
  	p->dst = walk->out;
  	list_add_tail(&p->entry, &walk->buffers);
  }
  
  static int skcipher_next_slow(struct skcipher_walk *walk, unsigned int bsize)
  {
  	bool phys = walk->flags & SKCIPHER_WALK_PHYS;
  	unsigned alignmask = walk->alignmask;
  	struct skcipher_walk_buffer *p;
  	unsigned a;
  	unsigned n;
  	u8 *buffer;
  	void *v;
  
  	if (!phys) {

  		if (!walk->buffer)
  			walk->buffer = walk->page;
  		buffer = walk->buffer;

  		if (buffer)
  			goto ok;
  	}
  
  	/* Start with the minimum alignment of kmalloc. */
  	a = crypto_tfm_ctx_alignment() - 1;
  	n = bsize;
  
  	if (phys) {
  		/* Calculate the minimum alignment of p->buffer. */
  		a &= (sizeof(*p) ^ (sizeof(*p) - 1)) >> 1;
  		n += sizeof(*p);
  	}
  
  	/* Minimum size to align p->buffer by alignmask. */
  	n += alignmask & ~a;
  
  	/* Minimum size to ensure p->buffer does not straddle a page. */
  	n += (bsize - 1) & ~(alignmask | a);
  
  	v = kzalloc(n, skcipher_walk_gfp(walk));
  	if (!v)
  		return skcipher_walk_done(walk, -ENOMEM);
  
  	if (phys) {
  		p = v;
  		p->len = bsize;
  		skcipher_queue_write(walk, p);
  		buffer = p->buffer;
  	} else {
  		walk->buffer = v;
  		buffer = v;
  	}
  
  ok:
  	walk->dst.virt.addr = PTR_ALIGN(buffer, alignmask + 1);
  	walk->dst.virt.addr = skcipher_get_spot(walk->dst.virt.addr, bsize);
  	walk->src.virt.addr = walk->dst.virt.addr;
  
  	scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
  
  	walk->nbytes = bsize;
  	walk->flags |= SKCIPHER_WALK_SLOW;
  
  	return 0;
  }
  
  static int skcipher_next_copy(struct skcipher_walk *walk)
  {
  	struct skcipher_walk_buffer *p;
  	u8 *tmp = walk->page;
  
  	skcipher_map_src(walk);
  	memcpy(tmp, walk->src.virt.addr, walk->nbytes);
  	skcipher_unmap_src(walk);
  
  	walk->src.virt.addr = tmp;
  	walk->dst.virt.addr = tmp;
  
  	if (!(walk->flags & SKCIPHER_WALK_PHYS))
  		return 0;
  
  	p = kmalloc(sizeof(*p), skcipher_walk_gfp(walk));
  	if (!p)
  		return -ENOMEM;
  
  	p->data = walk->page;
  	p->len = walk->nbytes;
  	skcipher_queue_write(walk, p);

  	if (offset_in_page(walk->page) + walk->nbytes + walk->stride >

  	    PAGE_SIZE)
  		walk->page = NULL;
  	else
  		walk->page += walk->nbytes;
  
  	return 0;
  }
  
  static int skcipher_next_fast(struct skcipher_walk *walk)
  {
  	unsigned long diff;
  
  	walk->src.phys.page = scatterwalk_page(&walk->in);
  	walk->src.phys.offset = offset_in_page(walk->in.offset);
  	walk->dst.phys.page = scatterwalk_page(&walk->out);
  	walk->dst.phys.offset = offset_in_page(walk->out.offset);
  
  	if (walk->flags & SKCIPHER_WALK_PHYS)
  		return 0;
  
  	diff = walk->src.phys.offset - walk->dst.phys.offset;
  	diff |= walk->src.virt.page - walk->dst.virt.page;
  
  	skcipher_map_src(walk);
  	walk->dst.virt.addr = walk->src.virt.addr;
  
  	if (diff) {
  		walk->flags |= SKCIPHER_WALK_DIFF;
  		skcipher_map_dst(walk);
  	}
  
  	return 0;
  }
  
  static int skcipher_walk_next(struct skcipher_walk *walk)
  {
  	unsigned int bsize;
  	unsigned int n;
  	int err;
  
  	walk->flags &= ~(SKCIPHER_WALK_SLOW | SKCIPHER_WALK_COPY |
  			 SKCIPHER_WALK_DIFF);
  
  	n = walk->total;

  	bsize = min(walk->stride, max(n, walk->blocksize));

  	n = scatterwalk_clamp(&walk->in, n);
  	n = scatterwalk_clamp(&walk->out, n);
  
  	if (unlikely(n < bsize)) {
  		if (unlikely(walk->total < walk->blocksize))
  			return skcipher_walk_done(walk, -EINVAL);
  
  slow_path:
  		err = skcipher_next_slow(walk, bsize);
  		goto set_phys_lowmem;
  	}
  
  	if (unlikely((walk->in.offset | walk->out.offset) & walk->alignmask)) {
  		if (!walk->page) {
  			gfp_t gfp = skcipher_walk_gfp(walk);
  
  			walk->page = (void *)__get_free_page(gfp);
  			if (!walk->page)
  				goto slow_path;
  		}
  
  		walk->nbytes = min_t(unsigned, n,
  				     PAGE_SIZE - offset_in_page(walk->page));
  		walk->flags |= SKCIPHER_WALK_COPY;
  		err = skcipher_next_copy(walk);
  		goto set_phys_lowmem;
  	}
  
  	walk->nbytes = n;
  
  	return skcipher_next_fast(walk);
  
  set_phys_lowmem:
  	if (!err && (walk->flags & SKCIPHER_WALK_PHYS)) {
  		walk->src.phys.page = virt_to_page(walk->src.virt.addr);
  		walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
  		walk->src.phys.offset &= PAGE_SIZE - 1;
  		walk->dst.phys.offset &= PAGE_SIZE - 1;
  	}
  	return err;
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_next);
  
  static int skcipher_copy_iv(struct skcipher_walk *walk)
  {
  	unsigned a = crypto_tfm_ctx_alignment() - 1;
  	unsigned alignmask = walk->alignmask;
  	unsigned ivsize = walk->ivsize;

  	unsigned bs = walk->stride;

  	unsigned aligned_bs;
  	unsigned size;
  	u8 *iv;

  	aligned_bs = ALIGN(bs, alignmask + 1);

  
  	/* Minimum size to align buffer by alignmask. */
  	size = alignmask & ~a;
  
  	if (walk->flags & SKCIPHER_WALK_PHYS)
  		size += ivsize;
  	else {
  		size += aligned_bs + ivsize;
  
  		/* Minimum size to ensure buffer does not straddle a page. */
  		size += (bs - 1) & ~(alignmask | a);
  	}
  
  	walk->buffer = kmalloc(size, skcipher_walk_gfp(walk));
  	if (!walk->buffer)
  		return -ENOMEM;
  
  	iv = PTR_ALIGN(walk->buffer, alignmask + 1);
  	iv = skcipher_get_spot(iv, bs) + aligned_bs;
  
  	walk->iv = memcpy(iv, walk->iv, walk->ivsize);
  	return 0;
  }
  
  static int skcipher_walk_first(struct skcipher_walk *walk)
  {

  	if (WARN_ON_ONCE(in_irq()))
  		return -EDEADLK;

  	walk->buffer = NULL;
  	if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
  		int err = skcipher_copy_iv(walk);
  		if (err)
  			return err;
  	}
  
  	walk->page = NULL;
  	walk->nbytes = walk->total;
  
  	return skcipher_walk_next(walk);
  }
  
  static int skcipher_walk_skcipher(struct skcipher_walk *walk,
  				  struct skcipher_request *req)
  {
  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

  	walk->total = req->cryptlen;
  	walk->nbytes = 0;

  	walk->iv = req->iv;
  	walk->oiv = req->iv;

  
  	if (unlikely(!walk->total))
  		return 0;

  	scatterwalk_start(&walk->in, req->src);
  	scatterwalk_start(&walk->out, req->dst);

  	walk->flags &= ~SKCIPHER_WALK_SLEEP;
  	walk->flags |= req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
  		       SKCIPHER_WALK_SLEEP : 0;
  
  	walk->blocksize = crypto_skcipher_blocksize(tfm);

  	walk->stride = crypto_skcipher_walksize(tfm);

  	walk->ivsize = crypto_skcipher_ivsize(tfm);
  	walk->alignmask = crypto_skcipher_alignmask(tfm);
  
  	return skcipher_walk_first(walk);
  }
  
  int skcipher_walk_virt(struct skcipher_walk *walk,
  		       struct skcipher_request *req, bool atomic)
  {
  	int err;
  
  	walk->flags &= ~SKCIPHER_WALK_PHYS;
  
  	err = skcipher_walk_skcipher(walk, req);
  
  	walk->flags &= atomic ? ~SKCIPHER_WALK_SLEEP : ~0;
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_virt);
  
  void skcipher_walk_atomise(struct skcipher_walk *walk)
  {
  	walk->flags &= ~SKCIPHER_WALK_SLEEP;
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_atomise);
  
  int skcipher_walk_async(struct skcipher_walk *walk,
  			struct skcipher_request *req)
  {
  	walk->flags |= SKCIPHER_WALK_PHYS;
  
  	INIT_LIST_HEAD(&walk->buffers);
  
  	return skcipher_walk_skcipher(walk, req);
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_async);

  static int skcipher_walk_aead_common(struct skcipher_walk *walk,
  				     struct aead_request *req, bool atomic)

  {
  	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
  	int err;

  	walk->nbytes = 0;

  	walk->iv = req->iv;
  	walk->oiv = req->iv;

  
  	if (unlikely(!walk->total))
  		return 0;

  	walk->flags &= ~SKCIPHER_WALK_PHYS;

  	scatterwalk_start(&walk->in, req->src);
  	scatterwalk_start(&walk->out, req->dst);
  
  	scatterwalk_copychunks(NULL, &walk->in, req->assoclen, 2);
  	scatterwalk_copychunks(NULL, &walk->out, req->assoclen, 2);

  	scatterwalk_done(&walk->in, 0, walk->total);
  	scatterwalk_done(&walk->out, 0, walk->total);

  	if (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP)
  		walk->flags |= SKCIPHER_WALK_SLEEP;
  	else
  		walk->flags &= ~SKCIPHER_WALK_SLEEP;
  
  	walk->blocksize = crypto_aead_blocksize(tfm);

  	walk->stride = crypto_aead_chunksize(tfm);

  	walk->ivsize = crypto_aead_ivsize(tfm);
  	walk->alignmask = crypto_aead_alignmask(tfm);
  
  	err = skcipher_walk_first(walk);
  
  	if (atomic)
  		walk->flags &= ~SKCIPHER_WALK_SLEEP;
  
  	return err;
  }

  
  int skcipher_walk_aead(struct skcipher_walk *walk, struct aead_request *req,
  		       bool atomic)
  {
  	walk->total = req->cryptlen;
  
  	return skcipher_walk_aead_common(walk, req, atomic);
  }

  EXPORT_SYMBOL_GPL(skcipher_walk_aead);

  int skcipher_walk_aead_encrypt(struct skcipher_walk *walk,
  			       struct aead_request *req, bool atomic)
  {
  	walk->total = req->cryptlen;
  
  	return skcipher_walk_aead_common(walk, req, atomic);
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_aead_encrypt);
  
  int skcipher_walk_aead_decrypt(struct skcipher_walk *walk,
  			       struct aead_request *req, bool atomic)
  {
  	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
  
  	walk->total = req->cryptlen - crypto_aead_authsize(tfm);
  
  	return skcipher_walk_aead_common(walk, req, atomic);
  }
  EXPORT_SYMBOL_GPL(skcipher_walk_aead_decrypt);

  static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
  {
  	if (alg->cra_type == &crypto_blkcipher_type)
  		return sizeof(struct crypto_blkcipher *);

  	if (alg->cra_type == &crypto_ablkcipher_type ||
  	    alg->cra_type == &crypto_givcipher_type)
  		return sizeof(struct crypto_ablkcipher *);

  	return crypto_alg_extsize(alg);

  }
  
  static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
  				     const u8 *key, unsigned int keylen)
  {
  	struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct crypto_blkcipher *blkcipher = *ctx;
  	int err;
  
  	crypto_blkcipher_clear_flags(blkcipher, ~0);
  	crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) &
  					      CRYPTO_TFM_REQ_MASK);
  	err = crypto_blkcipher_setkey(blkcipher, key, keylen);
  	crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
  				       CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int skcipher_crypt_blkcipher(struct skcipher_request *req,
  				    int (*crypt)(struct blkcipher_desc *,
  						 struct scatterlist *,
  						 struct scatterlist *,
  						 unsigned int))
  {
  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct blkcipher_desc desc = {
  		.tfm = *ctx,
  		.info = req->iv,
  		.flags = req->base.flags,
  	};
  
  
  	return crypt(&desc, req->dst, req->src, req->cryptlen);
  }
  
  static int skcipher_encrypt_blkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
  
  	return skcipher_crypt_blkcipher(req, alg->encrypt);
  }
  
  static int skcipher_decrypt_blkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
  
  	return skcipher_crypt_blkcipher(req, alg->decrypt);
  }
  
  static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
  {
  	struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
  
  	crypto_free_blkcipher(*ctx);
  }

  static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)

  {
  	struct crypto_alg *calg = tfm->__crt_alg;
  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
  	struct crypto_blkcipher *blkcipher;
  	struct crypto_tfm *btfm;
  
  	if (!crypto_mod_get(calg))
  		return -EAGAIN;
  
  	btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER,
  					CRYPTO_ALG_TYPE_MASK);
  	if (IS_ERR(btfm)) {
  		crypto_mod_put(calg);
  		return PTR_ERR(btfm);
  	}
  
  	blkcipher = __crypto_blkcipher_cast(btfm);
  	*ctx = blkcipher;
  	tfm->exit = crypto_exit_skcipher_ops_blkcipher;
  
  	skcipher->setkey = skcipher_setkey_blkcipher;
  	skcipher->encrypt = skcipher_encrypt_blkcipher;
  	skcipher->decrypt = skcipher_decrypt_blkcipher;
  
  	skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);

  	skcipher->keysize = calg->cra_blkcipher.max_keysize;

  
  	return 0;
  }
  
  static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
  				      const u8 *key, unsigned int keylen)
  {
  	struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct crypto_ablkcipher *ablkcipher = *ctx;
  	int err;
  
  	crypto_ablkcipher_clear_flags(ablkcipher, ~0);
  	crypto_ablkcipher_set_flags(ablkcipher,
  				    crypto_skcipher_get_flags(tfm) &
  				    CRYPTO_TFM_REQ_MASK);
  	err = crypto_ablkcipher_setkey(ablkcipher, key, keylen);
  	crypto_skcipher_set_flags(tfm,
  				  crypto_ablkcipher_get_flags(ablkcipher) &
  				  CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
  				     int (*crypt)(struct ablkcipher_request *))
  {
  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct ablkcipher_request *subreq = skcipher_request_ctx(req);
  
  	ablkcipher_request_set_tfm(subreq, *ctx);
  	ablkcipher_request_set_callback(subreq, skcipher_request_flags(req),
  					req->base.complete, req->base.data);
  	ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
  				     req->iv);
  
  	return crypt(subreq);
  }
  
  static int skcipher_encrypt_ablkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  
  	return skcipher_crypt_ablkcipher(req, alg->encrypt);
  }
  
  static int skcipher_decrypt_ablkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  
  	return skcipher_crypt_ablkcipher(req, alg->decrypt);
  }
  
  static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
  {
  	struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
  
  	crypto_free_ablkcipher(*ctx);
  }

  static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)

  {
  	struct crypto_alg *calg = tfm->__crt_alg;
  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
  	struct crypto_ablkcipher *ablkcipher;
  	struct crypto_tfm *abtfm;
  
  	if (!crypto_mod_get(calg))
  		return -EAGAIN;
  
  	abtfm = __crypto_alloc_tfm(calg, 0, 0);
  	if (IS_ERR(abtfm)) {
  		crypto_mod_put(calg);
  		return PTR_ERR(abtfm);
  	}
  
  	ablkcipher = __crypto_ablkcipher_cast(abtfm);
  	*ctx = ablkcipher;
  	tfm->exit = crypto_exit_skcipher_ops_ablkcipher;
  
  	skcipher->setkey = skcipher_setkey_ablkcipher;
  	skcipher->encrypt = skcipher_encrypt_ablkcipher;
  	skcipher->decrypt = skcipher_decrypt_ablkcipher;
  
  	skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher);
  	skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) +
  			    sizeof(struct ablkcipher_request);

  	skcipher->keysize = calg->cra_ablkcipher.max_keysize;

  
  	return 0;
  }

  static int skcipher_setkey_unaligned(struct crypto_skcipher *tfm,
  				     const u8 *key, unsigned int keylen)
  {
  	unsigned long alignmask = crypto_skcipher_alignmask(tfm);
  	struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
  	u8 *buffer, *alignbuffer;
  	unsigned long absize;
  	int ret;
  
  	absize = keylen + alignmask;
  	buffer = kmalloc(absize, GFP_ATOMIC);
  	if (!buffer)
  		return -ENOMEM;
  
  	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  	memcpy(alignbuffer, key, keylen);
  	ret = cipher->setkey(tfm, alignbuffer, keylen);
  	kzfree(buffer);
  	return ret;
  }
  
  static int skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
  			   unsigned int keylen)
  {
  	struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
  	unsigned long alignmask = crypto_skcipher_alignmask(tfm);
  
  	if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
  		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  		return -EINVAL;
  	}
  
  	if ((unsigned long)key & alignmask)
  		return skcipher_setkey_unaligned(tfm, key, keylen);
  
  	return cipher->setkey(tfm, key, keylen);
  }

  static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
  
  	alg->exit(skcipher);
  }

  static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
  {

  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);

  	if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
  		return crypto_init_skcipher_ops_blkcipher(tfm);

  	if (tfm->__crt_alg->cra_type == &crypto_ablkcipher_type ||
  	    tfm->__crt_alg->cra_type == &crypto_givcipher_type)
  		return crypto_init_skcipher_ops_ablkcipher(tfm);

  	skcipher->setkey = skcipher_setkey;

  	skcipher->encrypt = alg->encrypt;
  	skcipher->decrypt = alg->decrypt;
  	skcipher->ivsize = alg->ivsize;
  	skcipher->keysize = alg->max_keysize;
  
  	if (alg->exit)
  		skcipher->base.exit = crypto_skcipher_exit_tfm;

  	if (alg->init)
  		return alg->init(skcipher);
  
  	return 0;
  }
  
  static void crypto_skcipher_free_instance(struct crypto_instance *inst)
  {
  	struct skcipher_instance *skcipher =
  		container_of(inst, struct skcipher_instance, s.base);
  
  	skcipher->free(skcipher);
  }
  
  static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)

  	__maybe_unused;

  static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
  						     base);
  
  	seq_printf(m, "type         : skcipher
  ");
  	seq_printf(m, "async        : %s
  ",
  		   alg->cra_flags & CRYPTO_ALG_ASYNC ?  "yes" : "no");
  	seq_printf(m, "blocksize    : %u
  ", alg->cra_blocksize);
  	seq_printf(m, "min keysize  : %u
  ", skcipher->min_keysize);
  	seq_printf(m, "max keysize  : %u
  ", skcipher->max_keysize);
  	seq_printf(m, "ivsize       : %u
  ", skcipher->ivsize);
  	seq_printf(m, "chunksize    : %u
  ", skcipher->chunksize);

  	seq_printf(m, "walksize     : %u
  ", skcipher->walksize);

  }

  #ifdef CONFIG_NET
  static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	struct crypto_report_blkcipher rblkcipher;
  	struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
  						     base);
  
  	strncpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
  	strncpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
  
  	rblkcipher.blocksize = alg->cra_blocksize;
  	rblkcipher.min_keysize = skcipher->min_keysize;
  	rblkcipher.max_keysize = skcipher->max_keysize;
  	rblkcipher.ivsize = skcipher->ivsize;
  
  	if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
  		    sizeof(struct crypto_report_blkcipher), &rblkcipher))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }
  #else
  static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	return -ENOSYS;
  }
  #endif

  static const struct crypto_type crypto_skcipher_type2 = {
  	.extsize = crypto_skcipher_extsize,
  	.init_tfm = crypto_skcipher_init_tfm,

  	.free = crypto_skcipher_free_instance,
  #ifdef CONFIG_PROC_FS
  	.show = crypto_skcipher_show,
  #endif
  	.report = crypto_skcipher_report,

  	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
  	.maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,

  	.type = CRYPTO_ALG_TYPE_SKCIPHER,

  	.tfmsize = offsetof(struct crypto_skcipher, base),
  };

  int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn,

  			  const char *name, u32 type, u32 mask)
  {
  	spawn->base.frontend = &crypto_skcipher_type2;
  	return crypto_grab_spawn(&spawn->base, name, type, mask);
  }

  EXPORT_SYMBOL_GPL(crypto_grab_skcipher);

  struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
  					      u32 type, u32 mask)
  {
  	return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
  }
  EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);

  int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask)
  {
  	return crypto_type_has_alg(alg_name, &crypto_skcipher_type2,
  				   type, mask);
  }
  EXPORT_SYMBOL_GPL(crypto_has_skcipher2);
  
  static int skcipher_prepare_alg(struct skcipher_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;

  	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8 ||
  	    alg->walksize > PAGE_SIZE / 8)

  		return -EINVAL;
  
  	if (!alg->chunksize)
  		alg->chunksize = base->cra_blocksize;

  	if (!alg->walksize)
  		alg->walksize = alg->chunksize;

  
  	base->cra_type = &crypto_skcipher_type2;
  	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
  	base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;
  
  	return 0;
  }
  
  int crypto_register_skcipher(struct skcipher_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;
  	int err;
  
  	err = skcipher_prepare_alg(alg);
  	if (err)
  		return err;
  
  	return crypto_register_alg(base);
  }
  EXPORT_SYMBOL_GPL(crypto_register_skcipher);
  
  void crypto_unregister_skcipher(struct skcipher_alg *alg)
  {
  	crypto_unregister_alg(&alg->base);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);
  
  int crypto_register_skciphers(struct skcipher_alg *algs, int count)
  {
  	int i, ret;
  
  	for (i = 0; i < count; i++) {
  		ret = crypto_register_skcipher(&algs[i]);
  		if (ret)
  			goto err;
  	}
  
  	return 0;
  
  err:
  	for (--i; i >= 0; --i)
  		crypto_unregister_skcipher(&algs[i]);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(crypto_register_skciphers);
  
  void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
  {
  	int i;
  
  	for (i = count - 1; i >= 0; --i)
  		crypto_unregister_skcipher(&algs[i]);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);
  
  int skcipher_register_instance(struct crypto_template *tmpl,
  			   struct skcipher_instance *inst)
  {
  	int err;
  
  	err = skcipher_prepare_alg(&inst->alg);
  	if (err)
  		return err;
  
  	return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
  }
  EXPORT_SYMBOL_GPL(skcipher_register_instance);

  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Symmetric key cipher type");