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- /*
- * 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 <[email protected]>");
- MODULE_DESCRIPTION("Poly1305 authenticator");
- MODULE_ALIAS_CRYPTO("poly1305");
- MODULE_ALIAS_CRYPTO("poly1305-generic");
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