329 строки
8.5 KiB
C
329 строки
8.5 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/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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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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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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void poly1305_core_setkey(struct poly1305_key *key, const u8 *raw_key)
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{
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/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
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key->r[0] = (get_unaligned_le32(raw_key + 0) >> 0) & 0x3ffffff;
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key->r[1] = (get_unaligned_le32(raw_key + 3) >> 2) & 0x3ffff03;
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key->r[2] = (get_unaligned_le32(raw_key + 6) >> 4) & 0x3ffc0ff;
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key->r[3] = (get_unaligned_le32(raw_key + 9) >> 6) & 0x3f03fff;
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key->r[4] = (get_unaligned_le32(raw_key + 12) >> 8) & 0x00fffff;
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}
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EXPORT_SYMBOL_GPL(poly1305_core_setkey);
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/*
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* Poly1305 requires a unique key for each tag, which implies that we can't set
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* it on the tfm that gets accessed by multiple users simultaneously. Instead we
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* expect the key as the first 32 bytes in the update() call.
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*/
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unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx,
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const u8 *src, unsigned int srclen)
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{
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if (!dctx->sset) {
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if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) {
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poly1305_core_setkey(&dctx->r, src);
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src += POLY1305_BLOCK_SIZE;
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srclen -= POLY1305_BLOCK_SIZE;
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dctx->rset = true;
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}
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if (srclen >= POLY1305_BLOCK_SIZE) {
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dctx->s[0] = get_unaligned_le32(src + 0);
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dctx->s[1] = get_unaligned_le32(src + 4);
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dctx->s[2] = get_unaligned_le32(src + 8);
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dctx->s[3] = get_unaligned_le32(src + 12);
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src += POLY1305_BLOCK_SIZE;
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srclen -= POLY1305_BLOCK_SIZE;
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dctx->sset = true;
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}
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}
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return srclen;
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}
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EXPORT_SYMBOL_GPL(crypto_poly1305_setdesckey);
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static void poly1305_blocks_internal(struct poly1305_state *state,
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const struct poly1305_key *key,
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const void *src, unsigned int nblocks,
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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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if (!nblocks)
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return;
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r0 = key->r[0];
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r1 = key->r[1];
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r2 = key->r[2];
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r3 = key->r[3];
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r4 = key->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 = state->h[0];
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h1 = state->h[1];
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h2 = state->h[2];
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h3 = state->h[3];
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h4 = state->h[4];
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do {
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/* h += m[i] */
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h0 += (get_unaligned_le32(src + 0) >> 0) & 0x3ffffff;
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h1 += (get_unaligned_le32(src + 3) >> 2) & 0x3ffffff;
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h2 += (get_unaligned_le32(src + 6) >> 4) & 0x3ffffff;
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h3 += (get_unaligned_le32(src + 9) >> 6) & 0x3ffffff;
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h4 += (get_unaligned_le32(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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} while (--nblocks);
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state->h[0] = h0;
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state->h[1] = h1;
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state->h[2] = h2;
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state->h[3] = h3;
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state->h[4] = h4;
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}
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void poly1305_core_blocks(struct poly1305_state *state,
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const struct poly1305_key *key,
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const void *src, unsigned int nblocks)
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{
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poly1305_blocks_internal(state, key, src, nblocks, 1 << 24);
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}
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EXPORT_SYMBOL_GPL(poly1305_core_blocks);
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static void poly1305_blocks(struct poly1305_desc_ctx *dctx,
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const u8 *src, unsigned int srclen, u32 hibit)
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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_blocks_internal(&dctx->h, &dctx->r,
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src, srclen / POLY1305_BLOCK_SIZE, hibit);
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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, 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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poly1305_blocks(dctx, src, srclen, 1 << 24);
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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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void poly1305_core_emit(const struct poly1305_state *state, void *dst)
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{
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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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/* fully carry h */
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h0 = state->h[0];
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h1 = state->h[1];
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h2 = state->h[2];
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h3 = state->h[3];
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h4 = state->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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put_unaligned_le32((h0 >> 0) | (h1 << 26), dst + 0);
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put_unaligned_le32((h1 >> 6) | (h2 << 20), dst + 4);
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put_unaligned_le32((h2 >> 12) | (h3 << 14), dst + 8);
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put_unaligned_le32((h3 >> 18) | (h4 << 8), dst + 12);
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}
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EXPORT_SYMBOL_GPL(poly1305_core_emit);
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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_blocks(dctx, dctx->buf, POLY1305_BLOCK_SIZE, 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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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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