linux/lib/crypto/poly1305.c

79 lines
2.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Poly1305 authenticator algorithm, RFC7539
*
* Copyright (C) 2015 Martin Willi
*
* Based on public domain code by Andrew Moon and Daniel J. Bernstein.
*/
#include <crypto/internal/poly1305.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/unaligned.h>
void poly1305_init_generic(struct poly1305_desc_ctx *desc,
const u8 key[POLY1305_KEY_SIZE])
{
poly1305_core_setkey(&desc->core_r, key);
desc->s[0] = get_unaligned_le32(key + 16);
desc->s[1] = get_unaligned_le32(key + 20);
desc->s[2] = get_unaligned_le32(key + 24);
desc->s[3] = get_unaligned_le32(key + 28);
poly1305_core_init(&desc->h);
desc->buflen = 0;
desc->sset = true;
desc->rset = 2;
}
EXPORT_SYMBOL_GPL(poly1305_init_generic);
void poly1305_update_generic(struct poly1305_desc_ctx *desc, const u8 *src,
unsigned int nbytes)
{
unsigned int bytes;
if (unlikely(desc->buflen)) {
bytes = min(nbytes, POLY1305_BLOCK_SIZE - desc->buflen);
memcpy(desc->buf + desc->buflen, src, bytes);
src += bytes;
nbytes -= bytes;
desc->buflen += bytes;
if (desc->buflen == POLY1305_BLOCK_SIZE) {
poly1305_core_blocks(&desc->h, &desc->core_r, desc->buf,
1, 1);
desc->buflen = 0;
}
}
if (likely(nbytes >= POLY1305_BLOCK_SIZE)) {
poly1305_core_blocks(&desc->h, &desc->core_r, src,
nbytes / POLY1305_BLOCK_SIZE, 1);
src += nbytes - (nbytes % POLY1305_BLOCK_SIZE);
nbytes %= POLY1305_BLOCK_SIZE;
}
if (unlikely(nbytes)) {
desc->buflen = nbytes;
memcpy(desc->buf, src, nbytes);
}
}
EXPORT_SYMBOL_GPL(poly1305_update_generic);
void poly1305_final_generic(struct poly1305_desc_ctx *desc, u8 *dst)
{
if (unlikely(desc->buflen)) {
desc->buf[desc->buflen++] = 1;
memset(desc->buf + desc->buflen, 0,
POLY1305_BLOCK_SIZE - desc->buflen);
poly1305_core_blocks(&desc->h, &desc->core_r, desc->buf, 1, 0);
}
poly1305_core_emit(&desc->h, desc->s, dst);
*desc = (struct poly1305_desc_ctx){};
}
EXPORT_SYMBOL_GPL(poly1305_final_generic);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");