48ea8c6ebc
Move the core Poly1305 routines shared between the generic Poly1305 shash driver and the Adiantum and NHPoly1305 drivers into a separate library so that using just this pieces does not pull in the crypto API pieces of the generic Poly1305 routine. In a subsequent patch, we will augment this generic library with init/update/final routines so that Poyl1305 algorithm can be used directly without the need for using the crypto API's shash abstraction. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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 <asm/unaligned.h>
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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 = false;
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dctx->sset = false;
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return 0;
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}
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EXPORT_SYMBOL_GPL(crypto_poly1305_init);
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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->r, src,
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srclen / POLY1305_BLOCK_SIZE, 1);
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}
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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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EXPORT_SYMBOL_GPL(crypto_poly1305_update);
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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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__le32 digest[4];
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u64 f = 0;
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if (unlikely(!dctx->sset))
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return -ENOKEY;
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if (unlikely(dctx->buflen)) {
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dctx->buf[dctx->buflen++] = 1;
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memset(dctx->buf + dctx->buflen, 0,
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POLY1305_BLOCK_SIZE - dctx->buflen);
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poly1305_core_blocks(&dctx->h, &dctx->r, dctx->buf, 1, 0);
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}
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poly1305_core_emit(&dctx->h, digest);
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/* mac = (h + s) % (2^128) */
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f = (f >> 32) + le32_to_cpu(digest[0]) + dctx->s[0];
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put_unaligned_le32(f, dst + 0);
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f = (f >> 32) + le32_to_cpu(digest[1]) + dctx->s[1];
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put_unaligned_le32(f, dst + 4);
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f = (f >> 32) + le32_to_cpu(digest[2]) + dctx->s[2];
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put_unaligned_le32(f, dst + 8);
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f = (f >> 32) + le32_to_cpu(digest[3]) + dctx->s[3];
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put_unaligned_le32(f, dst + 12);
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return 0;
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}
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EXPORT_SYMBOL_GPL(crypto_poly1305_final);
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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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