| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
|---|
| 2 | /* |
|---|
| 3 | * The ChaCha stream cipher (RFC7539) |
|---|
| 4 | * |
|---|
| 5 | * Copyright (C) 2015 Martin Willi |
|---|
| 6 | */ |
|---|
| 7 | |
|---|
| 8 | #include <linux/kernel.h> |
|---|
| 9 | #include <linux/export.h> |
|---|
| 10 | #include <linux/module.h> |
|---|
| 11 | |
|---|
| 12 | #include <crypto/algapi.h> // for crypto_xor_cpy |
|---|
| 13 | #include <crypto/chacha.h> |
|---|
| 14 | |
|---|
| 15 | void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src, |
|---|
| 16 | unsigned int bytes, int nrounds) |
|---|
| 17 | { |
|---|
| 18 | /* aligned to potentially speed up crypto_xor() */ |
|---|
| 19 | u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long)); |
|---|
| 20 | |
|---|
| 21 | while (bytes >= CHACHA_BLOCK_SIZE) { |
|---|
| 22 | chacha_block_generic(state, stream, nrounds); |
|---|
| 23 | crypto_xor_cpy(dst, src1: src, src2: stream, CHACHA_BLOCK_SIZE); |
|---|
| 24 | bytes -= CHACHA_BLOCK_SIZE; |
|---|
| 25 | dst += CHACHA_BLOCK_SIZE; |
|---|
| 26 | src += CHACHA_BLOCK_SIZE; |
|---|
| 27 | } |
|---|
| 28 | if (bytes) { |
|---|
| 29 | chacha_block_generic(state, stream, nrounds); |
|---|
| 30 | crypto_xor_cpy(dst, src1: src, src2: stream, size: bytes); |
|---|
| 31 | } |
|---|
| 32 | } |
|---|
| 33 | EXPORT_SYMBOL(chacha_crypt_generic); |
|---|
| 34 | |
|---|
| 35 | MODULE_LICENSE("GPL" ); |
|---|
| 36 | |
|---|
