465 lines
11 KiB
C
465 lines
11 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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unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
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u8 buffer[bsize * 2 + alignmask];
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u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
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u8 *dst = src + 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, u8 *tmp)
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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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if (tmp) {
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memcpy(tmp, in->data, nbytes);
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src = tmp;
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dst = tmp;
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}
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nbytes = desc->prfn(desc, dst, src, nbytes);
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if (tmp)
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memcpy(out->data, tmp, 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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unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
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unsigned long buffer = 0;
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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 = nbytes;
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u8 *tmp = NULL;
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if (!scatterwalk_aligned(&walk_in, alignmask) ||
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!scatterwalk_aligned(&walk_out, alignmask)) {
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if (!buffer) {
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buffer = __get_free_page(GFP_ATOMIC);
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if (!buffer)
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n = 0;
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}
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tmp = (u8 *)buffer;
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}
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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, n);
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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, tmp);
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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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break;
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crypto_yield(tfm);
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}
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if (buffer)
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free_page(buffer);
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return 0;
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}
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static int crypt_iv_unaligned(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 crypto_tfm *tfm = desc->tfm;
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unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
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u8 *iv = desc->info;
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if (unlikely(((unsigned long)iv & alignmask))) {
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unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
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u8 buffer[ivsize + alignmask];
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u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
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int err;
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desc->info = memcpy(tmp, iv, ivsize);
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err = crypt(desc, dst, src, nbytes);
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memcpy(iv, tmp, ivsize);
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return err;
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}
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return crypt(desc, dst, src, nbytes);
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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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nbytes -= bsize;
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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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unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
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u8 stack[src == dst ? bsize + alignmask : 0];
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u8 *buf = (u8 *)ALIGN((unsigned long)stack, alignmask + 1);
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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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nbytes -= bsize;
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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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nbytes -= bsize;
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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_iv_unaligned(&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_iv_unaligned(&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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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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unsigned long align;
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unsigned long addr;
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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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align = crypto_tfm_alg_alignmask(tfm) + 1;
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addr = (unsigned long)crypto_tfm_ctx(tfm);
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addr = ALIGN(addr, align);
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addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
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ops->cit_iv = (void *)addr;
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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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}
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