crypto: poly1305 - Add a generic Poly1305 authenticator implementation
Poly1305 is a fast message authenticator designed by Daniel J. Bernstein. It is further defined in RFC7539 as a building block for the ChaCha20-Poly1305 AEAD for use in IETF protocols. This is a portable C implementation of the algorithm without architecture specific optimizations, based on public domain code by Daniel J. Bernstein and Andrew Moon. Signed-off-by: Martin Willi <martin@strongswan.org> Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Martin Willi
Herbert Xu
Родитель
3590ebf2b4
Коммит
f979e014c5
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@ -426,6 +426,15 @@ config CRYPTO_GHASH
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help
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GHASH is message digest algorithm for GCM (Galois/Counter Mode).
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config CRYPTO_POLY1305
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tristate "Poly1305 authenticator algorithm"
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help
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Poly1305 authenticator algorithm, RFC7539.
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Poly1305 is an authenticator algorithm designed by Daniel J. Bernstein.
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It is used for the ChaCha20-Poly1305 AEAD, specified in RFC7539 for use
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in IETF protocols. This is the portable C implementation of Poly1305.
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config CRYPTO_MD4
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tristate "MD4 digest algorithm"
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select CRYPTO_HASH
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@ -81,6 +81,7 @@ obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o
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obj-$(CONFIG_CRYPTO_SEED) += seed.o
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obj-$(CONFIG_CRYPTO_SALSA20) += salsa20_generic.o
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obj-$(CONFIG_CRYPTO_CHACHA20) += chacha20_generic.o
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obj-$(CONFIG_CRYPTO_POLY1305) += poly1305_generic.o
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obj-$(CONFIG_CRYPTO_DEFLATE) += deflate.o
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obj-$(CONFIG_CRYPTO_ZLIB) += zlib.o
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obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
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@ -0,0 +1,300 @@
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/*
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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 <linux/crypto.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#define POLY1305_BLOCK_SIZE 16
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#define POLY1305_KEY_SIZE 32
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#define POLY1305_DIGEST_SIZE 16
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struct poly1305_ctx {
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/* key */
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u32 r[5];
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/* finalize key */
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u32 s[4];
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};
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struct poly1305_desc_ctx {
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/* accumulator */
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u32 h[5];
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/* partial buffer */
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u8 buf[POLY1305_BLOCK_SIZE];
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/* bytes used in partial buffer */
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unsigned int buflen;
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};
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static inline u64 mlt(u64 a, u64 b)
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{
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return a * b;
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}
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static inline u32 sr(u64 v, u_char n)
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{
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return v >> n;
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}
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static inline u32 and(u32 v, u32 mask)
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{
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return v & mask;
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}
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static inline u32 le32_to_cpuvp(const void *p)
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{
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return le32_to_cpup(p);
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}
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static int 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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memset(dctx->h, 0, sizeof(dctx->h));
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dctx->buflen = 0;
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return 0;
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}
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static int poly1305_setkey(struct crypto_shash *tfm,
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const u8 *key, unsigned int keylen)
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{
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struct poly1305_ctx *ctx = crypto_shash_ctx(tfm);
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if (keylen != POLY1305_KEY_SIZE) {
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crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
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ctx->r[0] = (le32_to_cpuvp(key + 0) >> 0) & 0x3ffffff;
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ctx->r[1] = (le32_to_cpuvp(key + 3) >> 2) & 0x3ffff03;
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ctx->r[2] = (le32_to_cpuvp(key + 6) >> 4) & 0x3ffc0ff;
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ctx->r[3] = (le32_to_cpuvp(key + 9) >> 6) & 0x3f03fff;
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ctx->r[4] = (le32_to_cpuvp(key + 12) >> 8) & 0x00fffff;
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ctx->s[0] = le32_to_cpuvp(key + 16);
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ctx->s[1] = le32_to_cpuvp(key + 20);
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ctx->s[2] = le32_to_cpuvp(key + 24);
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ctx->s[3] = le32_to_cpuvp(key + 28);
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return 0;
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}
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static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
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struct poly1305_ctx *ctx, const u8 *src,
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unsigned int srclen, u32 hibit)
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{
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u32 r0, r1, r2, r3, r4;
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u32 s1, s2, s3, s4;
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u32 h0, h1, h2, h3, h4;
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u64 d0, d1, d2, d3, d4;
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r0 = ctx->r[0];
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r1 = ctx->r[1];
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r2 = ctx->r[2];
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r3 = ctx->r[3];
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r4 = ctx->r[4];
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s1 = r1 * 5;
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s2 = r2 * 5;
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s3 = r3 * 5;
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s4 = r4 * 5;
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h0 = dctx->h[0];
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h1 = dctx->h[1];
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h2 = dctx->h[2];
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h3 = dctx->h[3];
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h4 = dctx->h[4];
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while (likely(srclen >= POLY1305_BLOCK_SIZE)) {
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/* h += m[i] */
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h0 += (le32_to_cpuvp(src + 0) >> 0) & 0x3ffffff;
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h1 += (le32_to_cpuvp(src + 3) >> 2) & 0x3ffffff;
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h2 += (le32_to_cpuvp(src + 6) >> 4) & 0x3ffffff;
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h3 += (le32_to_cpuvp(src + 9) >> 6) & 0x3ffffff;
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h4 += (le32_to_cpuvp(src + 12) >> 8) | hibit;
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/* h *= r */
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d0 = mlt(h0, r0) + mlt(h1, s4) + mlt(h2, s3) +
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mlt(h3, s2) + mlt(h4, s1);
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d1 = mlt(h0, r1) + mlt(h1, r0) + mlt(h2, s4) +
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mlt(h3, s3) + mlt(h4, s2);
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d2 = mlt(h0, r2) + mlt(h1, r1) + mlt(h2, r0) +
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mlt(h3, s4) + mlt(h4, s3);
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d3 = mlt(h0, r3) + mlt(h1, r2) + mlt(h2, r1) +
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mlt(h3, r0) + mlt(h4, s4);
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d4 = mlt(h0, r4) + mlt(h1, r3) + mlt(h2, r2) +
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mlt(h3, r1) + mlt(h4, r0);
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/* (partial) h %= p */
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d1 += sr(d0, 26); h0 = and(d0, 0x3ffffff);
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d2 += sr(d1, 26); h1 = and(d1, 0x3ffffff);
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d3 += sr(d2, 26); h2 = and(d2, 0x3ffffff);
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d4 += sr(d3, 26); h3 = and(d3, 0x3ffffff);
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h0 += sr(d4, 26) * 5; h4 = and(d4, 0x3ffffff);
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h1 += h0 >> 26; h0 = h0 & 0x3ffffff;
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src += POLY1305_BLOCK_SIZE;
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srclen -= POLY1305_BLOCK_SIZE;
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}
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dctx->h[0] = h0;
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dctx->h[1] = h1;
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dctx->h[2] = h2;
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dctx->h[3] = h3;
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dctx->h[4] = h4;
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return srclen;
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}
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static int 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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struct poly1305_ctx *ctx = crypto_shash_ctx(desc->tfm);
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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, ctx, dctx->buf,
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POLY1305_BLOCK_SIZE, 1 << 24);
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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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bytes = poly1305_blocks(dctx, ctx, src, srclen, 1 << 24);
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src += srclen - bytes;
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srclen = bytes;
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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 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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struct poly1305_ctx *ctx = crypto_shash_ctx(desc->tfm);
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__le32 *mac = (__le32 *)dst;
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u32 h0, h1, h2, h3, h4;
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u32 g0, g1, g2, g3, g4;
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u32 mask;
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u64 f = 0;
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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_blocks(dctx, ctx, dctx->buf, POLY1305_BLOCK_SIZE, 0);
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}
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/* fully carry h */
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h0 = dctx->h[0];
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h1 = dctx->h[1];
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h2 = dctx->h[2];
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h3 = dctx->h[3];
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h4 = dctx->h[4];
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h2 += (h1 >> 26); h1 = h1 & 0x3ffffff;
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h3 += (h2 >> 26); h2 = h2 & 0x3ffffff;
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h4 += (h3 >> 26); h3 = h3 & 0x3ffffff;
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h0 += (h4 >> 26) * 5; h4 = h4 & 0x3ffffff;
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h1 += (h0 >> 26); h0 = h0 & 0x3ffffff;
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/* compute h + -p */
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g0 = h0 + 5;
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g1 = h1 + (g0 >> 26); g0 &= 0x3ffffff;
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g2 = h2 + (g1 >> 26); g1 &= 0x3ffffff;
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g3 = h3 + (g2 >> 26); g2 &= 0x3ffffff;
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g4 = h4 + (g3 >> 26) - (1 << 26); g3 &= 0x3ffffff;
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/* select h if h < p, or h + -p if h >= p */
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mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1;
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g0 &= mask;
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g1 &= mask;
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g2 &= mask;
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g3 &= mask;
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g4 &= mask;
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mask = ~mask;
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h0 = (h0 & mask) | g0;
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h1 = (h1 & mask) | g1;
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h2 = (h2 & mask) | g2;
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h3 = (h3 & mask) | g3;
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h4 = (h4 & mask) | g4;
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/* h = h % (2^128) */
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h0 = (h0 >> 0) | (h1 << 26);
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h1 = (h1 >> 6) | (h2 << 20);
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h2 = (h2 >> 12) | (h3 << 14);
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h3 = (h3 >> 18) | (h4 << 8);
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/* mac = (h + s) % (2^128) */
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f = (f >> 32) + h0 + ctx->s[0]; mac[0] = cpu_to_le32(f);
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f = (f >> 32) + h1 + ctx->s[1]; mac[1] = cpu_to_le32(f);
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f = (f >> 32) + h2 + ctx->s[2]; mac[2] = cpu_to_le32(f);
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f = (f >> 32) + h3 + ctx->s[3]; mac[3] = cpu_to_le32(f);
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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 = poly1305_init,
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.update = poly1305_update,
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.final = poly1305_final,
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.setkey = poly1305_setkey,
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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_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_alignmask = sizeof(u32) - 1,
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.cra_blocksize = POLY1305_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct poly1305_ctx),
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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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module_init(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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