diff options
Diffstat (limited to 'crypto/poly1305_generic.c')
| -rw-r--r-- | crypto/poly1305_generic.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/crypto/poly1305_generic.c b/crypto/poly1305_generic.c new file mode 100644 index 000000000..94af47eb6 --- /dev/null +++ b/crypto/poly1305_generic.c @@ -0,0 +1,149 @@ +/* + * 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"); |