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| 1 | +/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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1 | 2 | /* |
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2 | 3 | * CTR: Counter mode |
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3 | 4 | * |
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4 | 5 | * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> |
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5 | | - * |
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6 | | - * This program is free software; you can redistribute it and/or modify it |
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7 | | - * under the terms of the GNU General Public License as published by the Free |
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8 | | - * Software Foundation; either version 2 of the License, or (at your option) |
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9 | | - * any later version. |
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10 | | - * |
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11 | 6 | */ |
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12 | 7 | |
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13 | 8 | #ifndef _CRYPTO_CTR_H |
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14 | 9 | #define _CRYPTO_CTR_H |
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15 | 10 | |
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| 11 | +#include <crypto/algapi.h> |
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| 12 | +#include <crypto/internal/skcipher.h> |
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| 13 | +#include <linux/string.h> |
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| 14 | +#include <linux/types.h> |
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| 15 | + |
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16 | 16 | #define CTR_RFC3686_NONCE_SIZE 4 |
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17 | 17 | #define CTR_RFC3686_IV_SIZE 8 |
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18 | 18 | #define CTR_RFC3686_BLOCK_SIZE 16 |
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19 | 19 | |
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| 20 | +static inline int crypto_ctr_encrypt_walk(struct skcipher_request *req, |
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| 21 | + void (*fn)(struct crypto_skcipher *, |
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| 22 | + const u8 *, u8 *)) |
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| 23 | +{ |
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| 24 | + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); |
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| 25 | + int blocksize = crypto_skcipher_chunksize(tfm); |
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| 26 | + u8 buf[MAX_CIPHER_BLOCKSIZE]; |
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| 27 | + struct skcipher_walk walk; |
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| 28 | + int err; |
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| 29 | + |
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| 30 | + /* avoid integer division due to variable blocksize parameter */ |
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| 31 | + if (WARN_ON_ONCE(!is_power_of_2(blocksize))) |
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| 32 | + return -EINVAL; |
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| 33 | + |
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| 34 | + err = skcipher_walk_virt(&walk, req, false); |
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| 35 | + |
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| 36 | + while (walk.nbytes > 0) { |
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| 37 | + u8 *dst = walk.dst.virt.addr; |
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| 38 | + u8 *src = walk.src.virt.addr; |
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| 39 | + int nbytes = walk.nbytes; |
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| 40 | + int tail = 0; |
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| 41 | + |
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| 42 | + if (nbytes < walk.total) { |
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| 43 | + tail = walk.nbytes & (blocksize - 1); |
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| 44 | + nbytes -= tail; |
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| 45 | + } |
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| 46 | + |
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| 47 | + do { |
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| 48 | + int bsize = min(nbytes, blocksize); |
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| 49 | + |
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| 50 | + fn(tfm, walk.iv, buf); |
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| 51 | + |
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| 52 | + crypto_xor_cpy(dst, src, buf, bsize); |
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| 53 | + crypto_inc(walk.iv, blocksize); |
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| 54 | + |
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| 55 | + dst += bsize; |
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| 56 | + src += bsize; |
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| 57 | + nbytes -= bsize; |
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| 58 | + } while (nbytes > 0); |
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| 59 | + |
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| 60 | + err = skcipher_walk_done(&walk, tail); |
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| 61 | + } |
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| 62 | + return err; |
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| 63 | +} |
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| 64 | + |
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20 | 65 | #endif /* _CRYPTO_CTR_H */ |
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