150 lines
3.7 KiB
C
150 lines
3.7 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <crypto/algapi.h>
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#include <crypto/internal/hash.h>
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#include <crypto/internal/poly1305.h>
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#include <linux/crypto.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/unaligned.h>
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static int crypto_poly1305_init(struct shash_desc *desc)
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{
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struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
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poly1305_core_init(&dctx->h);
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dctx->buflen = 0;
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dctx->rset = 0;
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dctx->sset = false;
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return 0;
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}
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static unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx,
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const u8 *src, unsigned int srclen)
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{
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if (!dctx->sset) {
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if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) {
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poly1305_core_setkey(&dctx->core_r, src);
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src += POLY1305_BLOCK_SIZE;
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srclen -= POLY1305_BLOCK_SIZE;
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dctx->rset = 2;
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}
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if (srclen >= POLY1305_BLOCK_SIZE) {
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dctx->s[0] = get_unaligned_le32(src + 0);
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dctx->s[1] = get_unaligned_le32(src + 4);
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dctx->s[2] = get_unaligned_le32(src + 8);
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dctx->s[3] = get_unaligned_le32(src + 12);
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src += POLY1305_BLOCK_SIZE;
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srclen -= POLY1305_BLOCK_SIZE;
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dctx->sset = true;
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}
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}
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return srclen;
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}
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static void poly1305_blocks(struct poly1305_desc_ctx *dctx, const u8 *src,
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unsigned int srclen)
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{
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unsigned int datalen;
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if (unlikely(!dctx->sset)) {
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datalen = crypto_poly1305_setdesckey(dctx, src, srclen);
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src += srclen - datalen;
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srclen = datalen;
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}
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poly1305_core_blocks(&dctx->h, &dctx->core_r, src,
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srclen / POLY1305_BLOCK_SIZE, 1);
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}
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static int crypto_poly1305_update(struct shash_desc *desc,
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const u8 *src, unsigned int srclen)
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{
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struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
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unsigned int bytes;
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if (unlikely(dctx->buflen)) {
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bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
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memcpy(dctx->buf + dctx->buflen, src, bytes);
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src += bytes;
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srclen -= bytes;
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dctx->buflen += bytes;
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if (dctx->buflen == POLY1305_BLOCK_SIZE) {
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poly1305_blocks(dctx, dctx->buf,
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POLY1305_BLOCK_SIZE);
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dctx->buflen = 0;
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}
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}
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if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
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poly1305_blocks(dctx, src, srclen);
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src += srclen - (srclen % POLY1305_BLOCK_SIZE);
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srclen %= POLY1305_BLOCK_SIZE;
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}
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if (unlikely(srclen)) {
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dctx->buflen = srclen;
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memcpy(dctx->buf, src, srclen);
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}
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return 0;
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}
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static int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)
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{
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struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
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if (unlikely(!dctx->sset))
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return -ENOKEY;
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poly1305_final_generic(dctx, dst);
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return 0;
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}
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static struct shash_alg poly1305_alg = {
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.digestsize = POLY1305_DIGEST_SIZE,
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.init = crypto_poly1305_init,
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.update = crypto_poly1305_update,
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.final = crypto_poly1305_final,
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.descsize = sizeof(struct poly1305_desc_ctx),
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.base = {
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.cra_name = "poly1305",
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.cra_driver_name = "poly1305-generic",
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.cra_priority = 100,
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.cra_blocksize = POLY1305_BLOCK_SIZE,
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.cra_module = THIS_MODULE,
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},
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};
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static int __init poly1305_mod_init(void)
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{
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return crypto_register_shash(&poly1305_alg);
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}
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static void __exit poly1305_mod_exit(void)
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{
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crypto_unregister_shash(&poly1305_alg);
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}
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subsys_initcall(poly1305_mod_init);
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module_exit(poly1305_mod_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
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MODULE_DESCRIPTION("Poly1305 authenticator");
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MODULE_ALIAS_CRYPTO("poly1305");
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MODULE_ALIAS_CRYPTO("poly1305-generic");
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