| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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| 2 | /* |
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| 3 | * The ChaCha stream cipher (RFC7539) |
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| 4 | * |
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| 5 | * Copyright (C) 2015 Martin Willi |
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| 6 | */ |
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| 7 | |
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| 8 | #include <crypto/algapi.h> // for crypto_xor_cpy |
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| 9 | #include <crypto/chacha.h> |
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| 10 | #include <linux/export.h> |
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| 11 | #include <linux/kernel.h> |
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| 12 | #include <linux/module.h> |
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| 13 | |
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| 14 | static void __maybe_unused |
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| 15 | chacha_crypt_generic(struct chacha_state *state, u8 *dst, const u8 *src, |
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| 16 | unsigned int bytes, int nrounds) |
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| 17 | { |
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| 18 | /* aligned to potentially speed up crypto_xor() */ |
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| 19 | u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long)); |
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| 20 | |
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| 21 | while (bytes >= CHACHA_BLOCK_SIZE) { |
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| 22 | chacha_block_generic(state, out: stream, nrounds); |
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| 23 | crypto_xor_cpy(dst, src1: src, src2: stream, CHACHA_BLOCK_SIZE); |
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| 24 | bytes -= CHACHA_BLOCK_SIZE; |
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| 25 | dst += CHACHA_BLOCK_SIZE; |
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| 26 | src += CHACHA_BLOCK_SIZE; |
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| 27 | } |
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| 28 | if (bytes) { |
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| 29 | chacha_block_generic(state, out: stream, nrounds); |
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| 30 | crypto_xor_cpy(dst, src1: src, src2: stream, size: bytes); |
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| 31 | } |
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| 32 | } |
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| 33 | |
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| 34 | #ifdef CONFIG_CRYPTO_LIB_CHACHA_ARCH |
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| 35 | #include "chacha.h" /* $(SRCARCH)/chacha.h */ |
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| 36 | #else |
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| 37 | #define chacha_crypt_arch chacha_crypt_generic |
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| 38 | #define hchacha_block_arch hchacha_block_generic |
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| 39 | #endif |
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| 40 | |
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| 41 | void chacha_crypt(struct chacha_state *state, u8 *dst, const u8 *src, |
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| 42 | unsigned int bytes, int nrounds) |
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| 43 | { |
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| 44 | chacha_crypt_arch(state, dst, src, bytes, nrounds); |
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| 45 | } |
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| 46 | EXPORT_SYMBOL_GPL(chacha_crypt); |
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| 47 | |
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| 48 | void hchacha_block(const struct chacha_state *state, |
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| 49 | u32 out[HCHACHA_OUT_WORDS], int nrounds) |
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| 50 | { |
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| 51 | hchacha_block_arch(state, out, nrounds); |
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| 52 | } |
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| 53 | EXPORT_SYMBOL_GPL(hchacha_block); |
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| 54 | |
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| 55 | #ifdef chacha_mod_init_arch |
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| 56 | static int __init chacha_mod_init(void) |
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| 57 | { |
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| 58 | chacha_mod_init_arch(); |
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| 59 | return 0; |
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| 60 | } |
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| 61 | subsys_initcall(chacha_mod_init); |
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| 62 | |
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| 63 | static void __exit chacha_mod_exit(void) |
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| 64 | { |
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| 65 | } |
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| 66 | module_exit(chacha_mod_exit); |
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| 67 | #endif |
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| 68 | |
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| 69 | MODULE_DESCRIPTION("ChaCha stream cipher (RFC7539)" ); |
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| 70 | MODULE_LICENSE("GPL" ); |
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| 71 | |
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