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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/lib/crypto/poly1305.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 * Poly1305 authenticator algorithm, RFC7539

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 *

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 * Copyright (C) 2015 Martin Willi

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 *

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 * Based on public domain code by Andrew Moon and Daniel J. Bernstein.

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 */

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#include <crypto/internal/blockhash.h>

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#include <crypto/internal/poly1305.h>

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#include <linux/export.h>

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#include <linux/kernel.h>

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#include <linux/module.h>

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#include <linux/string.h>

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#include <linux/unaligned.h>

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void poly1305_init(struct poly1305_desc_ctx *desc,

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		   const u8 key[POLY1305_KEY_SIZE])

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{

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	desc->s[0] = get_unaligned_le32(key + 16);

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	desc->s[1] = get_unaligned_le32(key + 20);

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	desc->s[2] = get_unaligned_le32(key + 24);

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	desc->s[3] = get_unaligned_le32(key + 28);

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	desc->buflen = 0;

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	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

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		poly1305_block_init_arch(&desc->state, key);

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	else

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		poly1305_block_init_generic(&desc->state, key);

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}

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EXPORT_SYMBOL(poly1305_init);

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static inline void poly1305_blocks(struct poly1305_block_state *state,

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				   const u8 *src, unsigned int len)

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{

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	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

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		poly1305_blocks_arch(state, src, len, 1);

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	else

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		poly1305_blocks_generic(state, src, len, 1);

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}

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void poly1305_update(struct poly1305_desc_ctx *desc,

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		     const u8 *src, unsigned int nbytes)

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{

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	desc->buflen = BLOCK_HASH_UPDATE(poly1305_blocks, &desc->state,

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					 src, nbytes, POLY1305_BLOCK_SIZE,

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					 desc->buf, desc->buflen);

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}

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EXPORT_SYMBOL(poly1305_update);

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void poly1305_final(struct poly1305_desc_ctx *desc, u8 *dst)

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{

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	if (unlikely(desc->buflen)) {

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		desc->buf[desc->buflen++] = 1;

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		memset(desc->buf + desc->buflen, 0,

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		       POLY1305_BLOCK_SIZE - desc->buflen);

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		if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

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			poly1305_blocks_arch(&desc->state, desc->buf,

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					     POLY1305_BLOCK_SIZE, 0);

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		else

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			poly1305_blocks_generic(&desc->state, desc->buf,

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						POLY1305_BLOCK_SIZE, 0);

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	}

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	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

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		poly1305_emit_arch(&desc->state.h, dst, desc->s);

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	else

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		poly1305_emit_generic(&desc->state.h, dst, desc->s);

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	*desc = (struct poly1305_desc_ctx){};

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}

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EXPORT_SYMBOL(poly1305_final);

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MODULE_LICENSE("GPL");

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MODULE_AUTHOR("Martin Willi <[email protected]>");

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MODULE_DESCRIPTION("Poly1305 authenticator algorithm, RFC7539");

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