/* * Poly1305 authenticator algorithm, RFC7539 * * Copyright (C) 2015 Martin Willi * * Based on public domain code by Andrew Moon and Daniel J. Bernstein. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include <crypto/algapi.h> #include <crypto/internal/hash.h> #include <crypto/internal/poly1305.h> #include <linux/crypto.h> #include <linux/kernel.h> #include <linux/module.h> #include <asm/unaligned.h> static int crypto_poly1305_init(struct shash_desc *desc) { struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); poly1305_core_init(&dctx->h); dctx->buflen = 0; dctx->rset = 0; dctx->sset = false; return 0; } static unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx, const u8 *src, unsigned int srclen) { if (!dctx->sset) { if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) { poly1305_core_setkey(&dctx->core_r, src); src += POLY1305_BLOCK_SIZE; srclen -= POLY1305_BLOCK_SIZE; dctx->rset = 2; } if (srclen >= POLY1305_BLOCK_SIZE) { dctx->s[0] = get_unaligned_le32(src + 0); dctx->s[1] = get_unaligned_le32(src + 4); dctx->s[2] = get_unaligned_le32(src + 8); dctx->s[3] = get_unaligned_le32(src + 12); src += POLY1305_BLOCK_SIZE; srclen -= POLY1305_BLOCK_SIZE; dctx->sset = true; } } return srclen; } static void poly1305_blocks(struct poly1305_desc_ctx *dctx, const u8 *src, unsigned int srclen) { unsigned int datalen; if (unlikely(!dctx->sset)) { datalen = crypto_poly1305_setdesckey(dctx, src, srclen); src += srclen - datalen; srclen = datalen; } poly1305_core_blocks(&dctx->h, &dctx->core_r, src, srclen / POLY1305_BLOCK_SIZE, 1); } static int crypto_poly1305_update(struct shash_desc *desc, const u8 *src, unsigned int srclen) { struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); unsigned int bytes; if (unlikely(dctx->buflen)) { bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen); memcpy(dctx->buf + dctx->buflen, src, bytes); src += bytes; srclen -= bytes; dctx->buflen += bytes; if (dctx->buflen == POLY1305_BLOCK_SIZE) { poly1305_blocks(dctx, dctx->buf, POLY1305_BLOCK_SIZE); dctx->buflen = 0; } } if (likely(srclen >= POLY1305_BLOCK_SIZE)) { poly1305_blocks(dctx, src, srclen); src += srclen - (srclen % POLY1305_BLOCK_SIZE); srclen %= POLY1305_BLOCK_SIZE; } if (unlikely(srclen)) { dctx->buflen = srclen; memcpy(dctx->buf, src, srclen); } return 0; } static int crypto_poly1305_final(struct shash_desc *desc, u8 *dst) { struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); if (unlikely(!dctx->sset)) return -ENOKEY; poly1305_final_generic(dctx, dst); return 0; } static struct shash_alg poly1305_alg = { .digestsize = POLY1305_DIGEST_SIZE, .init = crypto_poly1305_init, .update = crypto_poly1305_update, .final = crypto_poly1305_final, .descsize = sizeof(struct poly1305_desc_ctx), .base = { .cra_name = "poly1305", .cra_driver_name = "poly1305-generic", .cra_priority = 100, .cra_blocksize = POLY1305_BLOCK_SIZE, .cra_module = THIS_MODULE, }, }; static int __init poly1305_mod_init(void) { return crypto_register_shash(&poly1305_alg); } static void __exit poly1305_mod_exit(void) { crypto_unregister_shash(&poly1305_alg); } subsys_initcall(poly1305_mod_init); module_exit(poly1305_mod_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Martin Willi <martin@strongswan.org>"); MODULE_DESCRIPTION("Poly1305 authenticator"); MODULE_ALIAS_CRYPTO("poly1305"); MODULE_ALIAS_CRYPTO("poly1305-generic");