crypto/cipher.c - kernel/msm - Gitiles

 /*
  * Cryptographic API.
  *
  * Cipher operations.
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  * Copyright (c) 2005 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 <linux/compiler.h>
 #include <linux/kernel.h>
 #include <linux/crypto.h>
 #include <linux/errno.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <asm/scatterlist.h>
 #include "internal.h"
 #include "scatterwalk.h"

 static inline void xor_64(u8 *a, const u8 *b)
 {
 	((u32 *)a)[0] ^= ((u32 *)b)[0];
 	((u32 *)a)[1] ^= ((u32 *)b)[1];
 }

 static inline void xor_128(u8 *a, const u8 *b)
 {
 	((u32 *)a)[0] ^= ((u32 *)b)[0];
 	((u32 *)a)[1] ^= ((u32 *)b)[1];
 	((u32 *)a)[2] ^= ((u32 *)b)[2];
 	((u32 *)a)[3] ^= ((u32 *)b)[3];
 }

 static unsigned int crypt_slow(const struct cipher_desc *desc,
 			       struct scatter_walk *in,
 			       struct scatter_walk *out, unsigned int bsize)
 {
 	unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
 	u8 buffer[bsize * 2 + alignmask];
 	u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 	u8 *dst = src + bsize;

 	scatterwalk_copychunks(src, in, bsize, 0);
 	desc->prfn(desc, dst, src, bsize);
 	scatterwalk_copychunks(dst, out, bsize, 1);

 	return bsize;
 }

 static inline unsigned int crypt_fast(const struct cipher_desc *desc,
 				      struct scatter_walk *in,
 				      struct scatter_walk *out,
 				      unsigned int nbytes, u8 *tmp)
 {
 	u8 *src, *dst;
 	u8 *real_src, *real_dst;

 	real_src = scatterwalk_map(in, 0);
 	real_dst = scatterwalk_map(out, 1);

 	src = real_src;
 	dst = scatterwalk_samebuf(in, out) ? src : real_dst;

 	if (tmp) {
 		memcpy(tmp, src, nbytes);
 		src = tmp;
 		dst = tmp;
 	}

 	nbytes = desc->prfn(desc, dst, src, nbytes);

 	if (tmp)
 		memcpy(real_dst, tmp, nbytes);

 	scatterwalk_unmap(real_src, 0);
 	scatterwalk_unmap(real_dst, 1);

 	scatterwalk_advance(in, nbytes);
 	scatterwalk_advance(out, nbytes);

 	return nbytes;
 }

 /*
  * 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.
  */
 static int crypt(const struct cipher_desc *desc,
 		 struct scatterlist *dst,
 		 struct scatterlist *src,
 		 unsigned int nbytes)
 {
 	struct scatter_walk walk_in, walk_out;
 	struct crypto_tfm *tfm = desc->tfm;
 	const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
 	unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
 	unsigned long buffer = 0;

 	if (!nbytes)
 		return 0;

 	if (nbytes % bsize) {
 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 		return -EINVAL;
 	}

 	scatterwalk_start(&walk_in, src);
 	scatterwalk_start(&walk_out, dst);

 	for(;;) {
 		unsigned int n = nbytes;
 		u8 *tmp = NULL;

 		if (!scatterwalk_aligned(&walk_in, alignmask) ||
 		    !scatterwalk_aligned(&walk_out, alignmask)) {
 			if (!buffer) {
 				buffer = __get_free_page(GFP_ATOMIC);
 				if (!buffer)
 					n = 0;
 			}
 			tmp = (u8 *)buffer;
 		}

 		n = scatterwalk_clamp(&walk_in, n);
 		n = scatterwalk_clamp(&walk_out, n);

 		if (likely(n >= bsize))
 			n = crypt_fast(desc, &walk_in, &walk_out, n, tmp);
 		else
 			n = crypt_slow(desc, &walk_in, &walk_out, bsize);

 		nbytes -= n;

 		scatterwalk_done(&walk_in, 0, nbytes);
 		scatterwalk_done(&walk_out, 1, nbytes);

 		if (!nbytes)
 			break;

 		crypto_yield(tfm->crt_flags);
 	}

 	if (buffer)
 		free_page(buffer);

 	return 0;
 }

 static int crypt_iv_unaligned(struct cipher_desc *desc,
 			      struct scatterlist *dst,
 			      struct scatterlist *src,
 			      unsigned int nbytes)
 {
 	struct crypto_tfm *tfm = desc->tfm;
 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 	u8 *iv = desc->info;

 	if (unlikely(((unsigned long)iv & alignmask))) {
 		unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
 		u8 buffer[ivsize + alignmask];
 		u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 		int err;

 		desc->info = memcpy(tmp, iv, ivsize);
 		err = crypt(desc, dst, src, nbytes);
 		memcpy(iv, tmp, ivsize);

 		return err;
 	}

 	return crypt(desc, dst, src, nbytes);
 }

 static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
 					u8 *dst, const u8 *src,
 					unsigned int nbytes)
 {
 	struct crypto_tfm *tfm = desc->tfm;
 	void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
 	int bsize = crypto_tfm_alg_blocksize(tfm);

 	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = desc->crfn;
 	u8 *iv = desc->info;
 	unsigned int done = 0;

 	nbytes -= bsize;

 	do {
 		xor(iv, src);
 		fn(tfm, dst, iv);
 		memcpy(iv, dst, bsize);

 		src += bsize;
 		dst += bsize;
 	} while ((done += bsize) <= nbytes);

 	return done;
 }

 static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
 					u8 *dst, const u8 *src,
 					unsigned int nbytes)
 {
 	struct crypto_tfm *tfm = desc->tfm;
 	void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
 	int bsize = crypto_tfm_alg_blocksize(tfm);
 	unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);

 	u8 stack[src == dst ? bsize + alignmask : 0];
 	u8 *buf = (u8 *)ALIGN((unsigned long)stack, alignmask + 1);
 	u8 **dst_p = src == dst ? &buf : &dst;

 	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = desc->crfn;
 	u8 *iv = desc->info;
 	unsigned int done = 0;

 	nbytes -= bsize;

 	do {
 		u8 *tmp_dst = *dst_p;

 		fn(tfm, tmp_dst, src);
 		xor(tmp_dst, iv);
 		memcpy(iv, src, bsize);
 		if (tmp_dst != dst)
 			memcpy(dst, tmp_dst, bsize);

 		src += bsize;
 		dst += bsize;
 	} while ((done += bsize) <= nbytes);

 	return done;
 }

 static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
 				const u8 *src, unsigned int nbytes)
 {
 	struct crypto_tfm *tfm = desc->tfm;
 	int bsize = crypto_tfm_alg_blocksize(tfm);
 	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = desc->crfn;
 	unsigned int done = 0;

 	nbytes -= bsize;

 	do {
 		fn(tfm, dst, src);

 		src += bsize;
 		dst += bsize;
 	} while ((done += bsize) <= nbytes);

 	return done;
 }

 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
 {
 	struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;

 	tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
 	if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
 		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 		return -EINVAL;
 	} else
 		return cia->cia_setkey(tfm, key, keylen);
 }

 static int ecb_encrypt(struct crypto_tfm *tfm,
 		       struct scatterlist *dst,
                        struct scatterlist *src, unsigned int nbytes)
 {
 	struct cipher_desc desc;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	desc.tfm = tfm;
 	desc.crfn = cipher->cia_encrypt;
 	desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;

 	return crypt(&desc, dst, src, nbytes);
 }

 static int ecb_decrypt(struct crypto_tfm *tfm,
                        struct scatterlist *dst,
                        struct scatterlist *src,
 		       unsigned int nbytes)
 {
 	struct cipher_desc desc;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	desc.tfm = tfm;
 	desc.crfn = cipher->cia_decrypt;
 	desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;

 	return crypt(&desc, dst, src, nbytes);
 }

 static int cbc_encrypt(struct crypto_tfm *tfm,
                        struct scatterlist *dst,
                        struct scatterlist *src,
 		       unsigned int nbytes)
 {
 	struct cipher_desc desc;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	desc.tfm = tfm;
 	desc.crfn = cipher->cia_encrypt;
 	desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
 	desc.info = tfm->crt_cipher.cit_iv;

 	return crypt(&desc, dst, src, nbytes);
 }

 static int cbc_encrypt_iv(struct crypto_tfm *tfm,
                           struct scatterlist *dst,
                           struct scatterlist *src,
                           unsigned int nbytes, u8 *iv)
 {
 	struct cipher_desc desc;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	desc.tfm = tfm;
 	desc.crfn = cipher->cia_encrypt;
 	desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
 	desc.info = iv;

 	return crypt_iv_unaligned(&desc, dst, src, nbytes);
 }

 static int cbc_decrypt(struct crypto_tfm *tfm,
                        struct scatterlist *dst,
                        struct scatterlist *src,
 		       unsigned int nbytes)
 {
 	struct cipher_desc desc;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	desc.tfm = tfm;
 	desc.crfn = cipher->cia_decrypt;
 	desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
 	desc.info = tfm->crt_cipher.cit_iv;

 	return crypt(&desc, dst, src, nbytes);
 }

 static int cbc_decrypt_iv(struct crypto_tfm *tfm,
                           struct scatterlist *dst,
                           struct scatterlist *src,
                           unsigned int nbytes, u8 *iv)
 {
 	struct cipher_desc desc;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	desc.tfm = tfm;
 	desc.crfn = cipher->cia_decrypt;
 	desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
 	desc.info = iv;

 	return crypt_iv_unaligned(&desc, dst, src, nbytes);
 }

 static int nocrypt(struct crypto_tfm *tfm,
                    struct scatterlist *dst,
                    struct scatterlist *src,
 		   unsigned int nbytes)
 {
 	return -ENOSYS;
 }

 static int nocrypt_iv(struct crypto_tfm *tfm,
                       struct scatterlist *dst,
                       struct scatterlist *src,
                       unsigned int nbytes, u8 *iv)
 {
 	return -ENOSYS;
 }

 int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
 {
 	u32 mode = flags & CRYPTO_TFM_MODE_MASK;
 	tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
 	return 0;
 }

 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
 					      const u8 *),
 				   struct crypto_tfm *tfm,
 				   u8 *dst, const u8 *src)
 {
 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 	unsigned int size = crypto_tfm_alg_blocksize(tfm);
 	u8 buffer[size + alignmask];
 	u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);

 	memcpy(tmp, src, size);
 	fn(tfm, tmp, tmp);
 	memcpy(dst, tmp, size);
 }

 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
 				     u8 *dst, const u8 *src)
 {
 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
 		cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
 		return;
 	}

 	cipher->cia_encrypt(tfm, dst, src);
 }

 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
 				     u8 *dst, const u8 *src)
 {
 	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
 		cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
 		return;
 	}

 	cipher->cia_decrypt(tfm, dst, src);
 }

 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 {
 	int ret = 0;
 	struct cipher_tfm *ops = &tfm->crt_cipher;
 	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

 	ops->cit_setkey = setkey;
 	ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 		cipher_encrypt_unaligned : cipher->cia_encrypt;
 	ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 		cipher_decrypt_unaligned : cipher->cia_decrypt;

 	switch (tfm->crt_cipher.cit_mode) {
 	case CRYPTO_TFM_MODE_ECB:
 		ops->cit_encrypt = ecb_encrypt;
 		ops->cit_decrypt = ecb_decrypt;
 		ops->cit_encrypt_iv = nocrypt_iv;
 		ops->cit_decrypt_iv = nocrypt_iv;
 		break;

 	case CRYPTO_TFM_MODE_CBC:
 		ops->cit_encrypt = cbc_encrypt;
 		ops->cit_decrypt = cbc_decrypt;
 		ops->cit_encrypt_iv = cbc_encrypt_iv;
 		ops->cit_decrypt_iv = cbc_decrypt_iv;
 		break;

 	case CRYPTO_TFM_MODE_CFB:
 		ops->cit_encrypt = nocrypt;
 		ops->cit_decrypt = nocrypt;
 		ops->cit_encrypt_iv = nocrypt_iv;
 		ops->cit_decrypt_iv = nocrypt_iv;
 		break;

 	case CRYPTO_TFM_MODE_CTR:
 		ops->cit_encrypt = nocrypt;
 		ops->cit_decrypt = nocrypt;
 		ops->cit_encrypt_iv = nocrypt_iv;
 		ops->cit_decrypt_iv = nocrypt_iv;
 		break;

 	default:
 		BUG();
 	}

 	if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
 		unsigned long align;
 		unsigned long addr;

 	    	switch (crypto_tfm_alg_blocksize(tfm)) {
 	    	case 8:
 	    		ops->cit_xor_block = xor_64;
 	    		break;

 	    	case 16:
 	    		ops->cit_xor_block = xor_128;
 	    		break;

 	    	default:
 	    		printk(KERN_WARNING "%s: block size %u not supported\n",
 	    		       crypto_tfm_alg_name(tfm),
 	    		       crypto_tfm_alg_blocksize(tfm));
 	    		ret = -EINVAL;
 	    		goto out;
 	    	}

 		ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
 		align = crypto_tfm_alg_alignmask(tfm) + 1;
 		addr = (unsigned long)crypto_tfm_ctx(tfm);
 		addr = ALIGN(addr, align);
 		addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 		ops->cit_iv = (void *)addr;
 	}

 out:
 	return ret;
 }

 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 {
 }
	/*
	* Cryptographic API.
	*
	* Cipher operations.
	*
	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
	* Copyright (c) 2005 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 <linux/compiler.h>
	#include <linux/kernel.h>
	#include <linux/crypto.h>
	#include <linux/errno.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/string.h>
	#include <asm/scatterlist.h>
	#include "internal.h"
	#include "scatterwalk.h"

	static inline void xor_64(u8 a, const u8 b)
	{
	((u32 )a)[0] ^= ((u32 )b)[0];
	((u32 )a)[1] ^= ((u32 )b)[1];
	}

	static inline void xor_128(u8 a, const u8 b)
	{
	((u32 )a)[0] ^= ((u32 )b)[0];
	((u32 )a)[1] ^= ((u32 )b)[1];
	((u32 )a)[2] ^= ((u32 )b)[2];
	((u32 )a)[3] ^= ((u32 )b)[3];
	}

	static unsigned int crypt_slow(const struct cipher_desc *desc,
	struct scatter_walk *in,
	struct scatter_walk *out, unsigned int bsize)
	{
	unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
	u8 buffer[bsize * 2 + alignmask];
	u8 src = (u8 )ALIGN((unsigned long)buffer, alignmask + 1);
	u8 *dst = src + bsize;

	scatterwalk_copychunks(src, in, bsize, 0);
	desc->prfn(desc, dst, src, bsize);
	scatterwalk_copychunks(dst, out, bsize, 1);

	return bsize;
	}

	static inline unsigned int crypt_fast(const struct cipher_desc *desc,
	struct scatter_walk *in,
	struct scatter_walk *out,
	unsigned int nbytes, u8 *tmp)
	{
	u8 src, dst;
	u8 real_src, real_dst;

	real_src = scatterwalk_map(in, 0);
	real_dst = scatterwalk_map(out, 1);

	src = real_src;
	dst = scatterwalk_samebuf(in, out) ? src : real_dst;

	if (tmp) {
	memcpy(tmp, src, nbytes);
	src = tmp;
	dst = tmp;
	}

	nbytes = desc->prfn(desc, dst, src, nbytes);

	if (tmp)
	memcpy(real_dst, tmp, nbytes);

	scatterwalk_unmap(real_src, 0);
	scatterwalk_unmap(real_dst, 1);

	scatterwalk_advance(in, nbytes);
	scatterwalk_advance(out, nbytes);

	return nbytes;
	}

	/*
	* 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.
	*/
	static int crypt(const struct cipher_desc *desc,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes)
	{
	struct scatter_walk walk_in, walk_out;
	struct crypto_tfm *tfm = desc->tfm;
	const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
	unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
	unsigned long buffer = 0;

	if (!nbytes)
	return 0;

	if (nbytes % bsize) {
	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
	return -EINVAL;
	}

	scatterwalk_start(&walk_in, src);
	scatterwalk_start(&walk_out, dst);

	for(;;) {
	unsigned int n = nbytes;
	u8 *tmp = NULL;

	if (!scatterwalk_aligned(&walk_in, alignmask) \|\|
	!scatterwalk_aligned(&walk_out, alignmask)) {
	if (!buffer) {
	buffer = __get_free_page(GFP_ATOMIC);
	if (!buffer)
	n = 0;
	}
	tmp = (u8 *)buffer;
	}

	n = scatterwalk_clamp(&walk_in, n);
	n = scatterwalk_clamp(&walk_out, n);

	if (likely(n >= bsize))
	n = crypt_fast(desc, &walk_in, &walk_out, n, tmp);
	else
	n = crypt_slow(desc, &walk_in, &walk_out, bsize);

	nbytes -= n;

	scatterwalk_done(&walk_in, 0, nbytes);
	scatterwalk_done(&walk_out, 1, nbytes);

	if (!nbytes)
	break;

	crypto_yield(tfm->crt_flags);
	}

	if (buffer)
	free_page(buffer);

	return 0;
	}

	static int crypt_iv_unaligned(struct cipher_desc *desc,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes)
	{
	struct crypto_tfm *tfm = desc->tfm;
	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
	u8 *iv = desc->info;

	if (unlikely(((unsigned long)iv & alignmask))) {
	unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
	u8 buffer[ivsize + alignmask];
	u8 tmp = (u8 )ALIGN((unsigned long)buffer, alignmask + 1);
	int err;

	desc->info = memcpy(tmp, iv, ivsize);
	err = crypt(desc, dst, src, nbytes);
	memcpy(iv, tmp, ivsize);

	return err;
	}

	return crypt(desc, dst, src, nbytes);
	}

	static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
	u8 dst, const u8 src,
	unsigned int nbytes)
	{
	struct crypto_tfm *tfm = desc->tfm;
	void (xor)(u8 , const u8 *) = tfm->crt_u.cipher.cit_xor_block;
	int bsize = crypto_tfm_alg_blocksize(tfm);

	void (fn)(struct crypto_tfm , u8 , const u8 ) = desc->crfn;
	u8 *iv = desc->info;
	unsigned int done = 0;

	nbytes -= bsize;

	do {
	xor(iv, src);
	fn(tfm, dst, iv);
	memcpy(iv, dst, bsize);

	src += bsize;
	dst += bsize;
	} while ((done += bsize) <= nbytes);

	return done;
	}

	static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
	u8 dst, const u8 src,
	unsigned int nbytes)
	{
	struct crypto_tfm *tfm = desc->tfm;
	void (xor)(u8 , const u8 *) = tfm->crt_u.cipher.cit_xor_block;
	int bsize = crypto_tfm_alg_blocksize(tfm);
	unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);

	u8 stack[src == dst ? bsize + alignmask : 0];
	u8 buf = (u8 )ALIGN((unsigned long)stack, alignmask + 1);
	u8 **dst_p = src == dst ? &buf : &dst;

	void (fn)(struct crypto_tfm , u8 , const u8 ) = desc->crfn;
	u8 *iv = desc->info;
	unsigned int done = 0;

	nbytes -= bsize;

	do {
	u8 tmp_dst = dst_p;

	fn(tfm, tmp_dst, src);
	xor(tmp_dst, iv);
	memcpy(iv, src, bsize);
	if (tmp_dst != dst)
	memcpy(dst, tmp_dst, bsize);

	src += bsize;
	dst += bsize;
	} while ((done += bsize) <= nbytes);

	return done;
	}

	static unsigned int ecb_process(const struct cipher_desc desc, u8 dst,
	const u8 *src, unsigned int nbytes)
	{
	struct crypto_tfm *tfm = desc->tfm;
	int bsize = crypto_tfm_alg_blocksize(tfm);
	void (fn)(struct crypto_tfm , u8 , const u8 ) = desc->crfn;
	unsigned int done = 0;

	nbytes -= bsize;

	do {
	fn(tfm, dst, src);

	src += bsize;
	dst += bsize;
	} while ((done += bsize) <= nbytes);

	return done;
	}

	static int setkey(struct crypto_tfm tfm, const u8 key, unsigned int keylen)
	{
	struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;

	tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
	if (keylen < cia->cia_min_keysize \|\| keylen > cia->cia_max_keysize) {
	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
	return -EINVAL;
	} else
	return cia->cia_setkey(tfm, key, keylen);
	}

	static int ecb_encrypt(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src, unsigned int nbytes)
	{
	struct cipher_desc desc;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	desc.tfm = tfm;
	desc.crfn = cipher->cia_encrypt;
	desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;

	return crypt(&desc, dst, src, nbytes);
	}

	static int ecb_decrypt(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes)
	{
	struct cipher_desc desc;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	desc.tfm = tfm;
	desc.crfn = cipher->cia_decrypt;
	desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;

	return crypt(&desc, dst, src, nbytes);
	}

	static int cbc_encrypt(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes)
	{
	struct cipher_desc desc;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	desc.tfm = tfm;
	desc.crfn = cipher->cia_encrypt;
	desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
	desc.info = tfm->crt_cipher.cit_iv;

	return crypt(&desc, dst, src, nbytes);
	}

	static int cbc_encrypt_iv(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes, u8 *iv)
	{
	struct cipher_desc desc;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	desc.tfm = tfm;
	desc.crfn = cipher->cia_encrypt;
	desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
	desc.info = iv;

	return crypt_iv_unaligned(&desc, dst, src, nbytes);
	}

	static int cbc_decrypt(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes)
	{
	struct cipher_desc desc;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	desc.tfm = tfm;
	desc.crfn = cipher->cia_decrypt;
	desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
	desc.info = tfm->crt_cipher.cit_iv;

	return crypt(&desc, dst, src, nbytes);
	}

	static int cbc_decrypt_iv(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes, u8 *iv)
	{
	struct cipher_desc desc;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	desc.tfm = tfm;
	desc.crfn = cipher->cia_decrypt;
	desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
	desc.info = iv;

	return crypt_iv_unaligned(&desc, dst, src, nbytes);
	}

	static int nocrypt(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes)
	{
	return -ENOSYS;
	}

	static int nocrypt_iv(struct crypto_tfm *tfm,
	struct scatterlist *dst,
	struct scatterlist *src,
	unsigned int nbytes, u8 *iv)
	{
	return -ENOSYS;
	}

	int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
	{
	u32 mode = flags & CRYPTO_TFM_MODE_MASK;
	tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
	return 0;
	}

	static void cipher_crypt_unaligned(void (fn)(struct crypto_tfm , u8 *,
	const u8 *),
	struct crypto_tfm *tfm,
	u8 dst, const u8 src)
	{
	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
	unsigned int size = crypto_tfm_alg_blocksize(tfm);
	u8 buffer[size + alignmask];
	u8 tmp = (u8 )ALIGN((unsigned long)buffer, alignmask + 1);

	memcpy(tmp, src, size);
	fn(tfm, tmp, tmp);
	memcpy(dst, tmp, size);
	}

	static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
	u8 dst, const u8 src)
	{
	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	if (unlikely(((unsigned long)dst \| (unsigned long)src) & alignmask)) {
	cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
	return;
	}

	cipher->cia_encrypt(tfm, dst, src);
	}

	static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
	u8 dst, const u8 src)
	{
	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	if (unlikely(((unsigned long)dst \| (unsigned long)src) & alignmask)) {
	cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
	return;
	}

	cipher->cia_decrypt(tfm, dst, src);
	}

	int crypto_init_cipher_ops(struct crypto_tfm *tfm)
	{
	int ret = 0;
	struct cipher_tfm *ops = &tfm->crt_cipher;
	struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;

	ops->cit_setkey = setkey;
	ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
	cipher_encrypt_unaligned : cipher->cia_encrypt;
	ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
	cipher_decrypt_unaligned : cipher->cia_decrypt;

	switch (tfm->crt_cipher.cit_mode) {
	case CRYPTO_TFM_MODE_ECB:
	ops->cit_encrypt = ecb_encrypt;
	ops->cit_decrypt = ecb_decrypt;
	ops->cit_encrypt_iv = nocrypt_iv;
	ops->cit_decrypt_iv = nocrypt_iv;
	break;

	case CRYPTO_TFM_MODE_CBC:
	ops->cit_encrypt = cbc_encrypt;
	ops->cit_decrypt = cbc_decrypt;
	ops->cit_encrypt_iv = cbc_encrypt_iv;
	ops->cit_decrypt_iv = cbc_decrypt_iv;
	break;

	case CRYPTO_TFM_MODE_CFB:
	ops->cit_encrypt = nocrypt;
	ops->cit_decrypt = nocrypt;
	ops->cit_encrypt_iv = nocrypt_iv;
	ops->cit_decrypt_iv = nocrypt_iv;
	break;

	case CRYPTO_TFM_MODE_CTR:
	ops->cit_encrypt = nocrypt;
	ops->cit_decrypt = nocrypt;
	ops->cit_encrypt_iv = nocrypt_iv;
	ops->cit_decrypt_iv = nocrypt_iv;
	break;

	default:
	BUG();
	}

	if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
	unsigned long align;
	unsigned long addr;

	switch (crypto_tfm_alg_blocksize(tfm)) {
	case 8:
	ops->cit_xor_block = xor_64;
	break;

	case 16:
	ops->cit_xor_block = xor_128;
	break;

	default:
	printk(KERN_WARNING "%s: block size %u not supported\n",
	crypto_tfm_alg_name(tfm),
	crypto_tfm_alg_blocksize(tfm));
	ret = -EINVAL;
	goto out;
	}

	ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
	align = crypto_tfm_alg_alignmask(tfm) + 1;
	addr = (unsigned long)crypto_tfm_ctx(tfm);
	addr = ALIGN(addr, align);
	addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
	ops->cit_iv = (void *)addr;
	}

	out:
	return ret;
	}

	void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
	{
	}