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40725181b7
This patch adds hooks for cipher algorithms to implement multi-block ECB/CBC operations directly. This is expected to provide significant performance boots to the VIA Padlock. It could also be used for improving software implementations such as AES where operating on multiple blocks at a time may enable certain optimisations. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
404 lines
9.7 KiB
C
404 lines
9.7 KiB
C
/*
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* Cryptographic API.
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*
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* Cipher operations.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/compiler.h>
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#include <linux/kernel.h>
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#include <linux/crypto.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <asm/scatterlist.h>
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#include "internal.h"
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#include "scatterwalk.h"
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static inline void xor_64(u8 *a, const u8 *b)
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{
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((u32 *)a)[0] ^= ((u32 *)b)[0];
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((u32 *)a)[1] ^= ((u32 *)b)[1];
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}
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static inline void xor_128(u8 *a, const u8 *b)
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{
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((u32 *)a)[0] ^= ((u32 *)b)[0];
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((u32 *)a)[1] ^= ((u32 *)b)[1];
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((u32 *)a)[2] ^= ((u32 *)b)[2];
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((u32 *)a)[3] ^= ((u32 *)b)[3];
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}
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static unsigned int crypt_slow(const struct cipher_desc *desc,
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struct scatter_walk *in,
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struct scatter_walk *out, unsigned int bsize)
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{
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u8 src[bsize];
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u8 dst[bsize];
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unsigned int n;
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n = scatterwalk_copychunks(src, in, bsize, 0);
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scatterwalk_advance(in, n);
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desc->prfn(desc, dst, src, bsize);
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n = scatterwalk_copychunks(dst, out, bsize, 1);
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scatterwalk_advance(out, n);
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return bsize;
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}
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static inline unsigned int crypt_fast(const struct cipher_desc *desc,
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struct scatter_walk *in,
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struct scatter_walk *out,
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unsigned int nbytes)
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{
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u8 *src, *dst;
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src = in->data;
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dst = scatterwalk_samebuf(in, out) ? src : out->data;
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nbytes = desc->prfn(desc, dst, src, nbytes);
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scatterwalk_advance(in, nbytes);
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scatterwalk_advance(out, nbytes);
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return nbytes;
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}
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/*
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* Generic encrypt/decrypt wrapper for ciphers, handles operations across
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* multiple page boundaries by using temporary blocks. In user context,
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* the kernel is given a chance to schedule us once per page.
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*/
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static int crypt(const struct cipher_desc *desc,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes)
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{
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struct scatter_walk walk_in, walk_out;
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struct crypto_tfm *tfm = desc->tfm;
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const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
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if (!nbytes)
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return 0;
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if (nbytes % bsize) {
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tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
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return -EINVAL;
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}
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scatterwalk_start(&walk_in, src);
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scatterwalk_start(&walk_out, dst);
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for(;;) {
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unsigned int n;
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scatterwalk_map(&walk_in, 0);
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scatterwalk_map(&walk_out, 1);
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n = scatterwalk_clamp(&walk_in, nbytes);
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n = scatterwalk_clamp(&walk_out, n);
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if (likely(n >= bsize))
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n = crypt_fast(desc, &walk_in, &walk_out, n);
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else
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n = crypt_slow(desc, &walk_in, &walk_out, bsize);
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nbytes -= n;
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scatterwalk_done(&walk_in, 0, nbytes);
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scatterwalk_done(&walk_out, 1, nbytes);
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if (!nbytes)
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return 0;
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crypto_yield(tfm);
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}
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}
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static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
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u8 *dst, const u8 *src,
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unsigned int nbytes)
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{
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struct crypto_tfm *tfm = desc->tfm;
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void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
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int bsize = crypto_tfm_alg_blocksize(tfm);
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void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
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u8 *iv = desc->info;
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unsigned int done = 0;
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do {
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xor(iv, src);
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fn(crypto_tfm_ctx(tfm), dst, iv);
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memcpy(iv, dst, bsize);
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src += bsize;
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dst += bsize;
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} while ((done += bsize) < nbytes);
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return done;
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}
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static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
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u8 *dst, const u8 *src,
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unsigned int nbytes)
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{
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struct crypto_tfm *tfm = desc->tfm;
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void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
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int bsize = crypto_tfm_alg_blocksize(tfm);
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u8 stack[src == dst ? bsize : 0];
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u8 *buf = stack;
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u8 **dst_p = src == dst ? &buf : &dst;
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void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
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u8 *iv = desc->info;
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unsigned int done = 0;
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do {
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u8 *tmp_dst = *dst_p;
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fn(crypto_tfm_ctx(tfm), tmp_dst, src);
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xor(tmp_dst, iv);
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memcpy(iv, src, bsize);
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if (tmp_dst != dst)
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memcpy(dst, tmp_dst, bsize);
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src += bsize;
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dst += bsize;
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} while ((done += bsize) < nbytes);
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return done;
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}
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static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
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const u8 *src, unsigned int nbytes)
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{
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struct crypto_tfm *tfm = desc->tfm;
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int bsize = crypto_tfm_alg_blocksize(tfm);
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void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
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unsigned int done = 0;
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do {
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fn(crypto_tfm_ctx(tfm), dst, src);
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src += bsize;
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dst += bsize;
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} while ((done += bsize) < nbytes);
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return done;
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}
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static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
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{
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struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
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if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
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tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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} else
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return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
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&tfm->crt_flags);
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}
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static int ecb_encrypt(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src, unsigned int nbytes)
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{
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struct cipher_desc desc;
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struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
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desc.tfm = tfm;
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desc.crfn = cipher->cia_encrypt;
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desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;
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return crypt(&desc, dst, src, nbytes);
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}
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static int ecb_decrypt(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes)
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{
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struct cipher_desc desc;
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struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
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desc.tfm = tfm;
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desc.crfn = cipher->cia_decrypt;
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desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;
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return crypt(&desc, dst, src, nbytes);
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}
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static int cbc_encrypt(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes)
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{
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struct cipher_desc desc;
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struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
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desc.tfm = tfm;
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desc.crfn = cipher->cia_encrypt;
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desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
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desc.info = tfm->crt_cipher.cit_iv;
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return crypt(&desc, dst, src, nbytes);
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}
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static int cbc_encrypt_iv(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes, u8 *iv)
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{
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struct cipher_desc desc;
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struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
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desc.tfm = tfm;
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desc.crfn = cipher->cia_encrypt;
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desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
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desc.info = iv;
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return crypt(&desc, dst, src, nbytes);
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}
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static int cbc_decrypt(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes)
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{
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struct cipher_desc desc;
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struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
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desc.tfm = tfm;
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desc.crfn = cipher->cia_decrypt;
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desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
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desc.info = tfm->crt_cipher.cit_iv;
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return crypt(&desc, dst, src, nbytes);
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}
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static int cbc_decrypt_iv(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes, u8 *iv)
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{
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struct cipher_desc desc;
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struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
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desc.tfm = tfm;
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desc.crfn = cipher->cia_decrypt;
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desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
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desc.info = iv;
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return crypt(&desc, dst, src, nbytes);
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}
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static int nocrypt(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes)
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{
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return -ENOSYS;
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}
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static int nocrypt_iv(struct crypto_tfm *tfm,
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struct scatterlist *dst,
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struct scatterlist *src,
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unsigned int nbytes, u8 *iv)
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{
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return -ENOSYS;
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}
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int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
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{
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u32 mode = flags & CRYPTO_TFM_MODE_MASK;
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tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
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if (flags & CRYPTO_TFM_REQ_WEAK_KEY)
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tfm->crt_flags = CRYPTO_TFM_REQ_WEAK_KEY;
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return 0;
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}
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int crypto_init_cipher_ops(struct crypto_tfm *tfm)
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{
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int ret = 0;
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struct cipher_tfm *ops = &tfm->crt_cipher;
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ops->cit_setkey = setkey;
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switch (tfm->crt_cipher.cit_mode) {
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case CRYPTO_TFM_MODE_ECB:
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ops->cit_encrypt = ecb_encrypt;
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ops->cit_decrypt = ecb_decrypt;
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break;
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case CRYPTO_TFM_MODE_CBC:
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ops->cit_encrypt = cbc_encrypt;
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ops->cit_decrypt = cbc_decrypt;
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ops->cit_encrypt_iv = cbc_encrypt_iv;
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ops->cit_decrypt_iv = cbc_decrypt_iv;
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break;
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case CRYPTO_TFM_MODE_CFB:
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ops->cit_encrypt = nocrypt;
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ops->cit_decrypt = nocrypt;
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ops->cit_encrypt_iv = nocrypt_iv;
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ops->cit_decrypt_iv = nocrypt_iv;
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break;
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case CRYPTO_TFM_MODE_CTR:
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ops->cit_encrypt = nocrypt;
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ops->cit_decrypt = nocrypt;
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ops->cit_encrypt_iv = nocrypt_iv;
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ops->cit_decrypt_iv = nocrypt_iv;
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break;
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default:
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BUG();
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}
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if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
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switch (crypto_tfm_alg_blocksize(tfm)) {
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case 8:
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ops->cit_xor_block = xor_64;
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break;
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case 16:
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ops->cit_xor_block = xor_128;
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break;
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default:
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printk(KERN_WARNING "%s: block size %u not supported\n",
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crypto_tfm_alg_name(tfm),
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crypto_tfm_alg_blocksize(tfm));
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ret = -EINVAL;
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goto out;
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}
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ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
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ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
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if (ops->cit_iv == NULL)
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ret = -ENOMEM;
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}
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out:
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return ret;
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}
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void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
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{
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kfree(tfm->crt_cipher.cit_iv);
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}
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