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// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* This is based in part on Andrew Moon's poly1305-donna, which is in the
* public domain.
*/
#include <linux/kernel.h>
#include <asm/unaligned.h>
#include <crypto/internal/poly1305.h>
typedef __uint128_t u128;
void poly1305_core_setkey(struct poly1305_core_key *key,
const u8 raw_key[POLY1305_BLOCK_SIZE])
{
u64 t0, t1;
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
t0 = get_unaligned_le64(&raw_key[0]);
t1 = get_unaligned_le64(&raw_key[8]);
key->key.r64[0] = t0 & 0xffc0fffffffULL;
key->key.r64[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffffULL;
key->key.r64[2] = ((t1 >> 24)) & 0x00ffffffc0fULL;
/* s = 20*r */
key->precomputed_s.r64[0] = key->key.r64[1] * 20;
key->precomputed_s.r64[1] = key->key.r64[2] * 20;
}
EXPORT_SYMBOL(poly1305_core_setkey);
void poly1305_core_blocks(struct poly1305_state *state,
const struct poly1305_core_key *key, const void *src,
unsigned int nblocks, u32 hibit)
{
const u8 *input = src;
u64 hibit64;
u64 r0, r1, r2;
u64 s1, s2;
u64 h0, h1, h2;
u64 c;
u128 d0, d1, d2, d;
if (!nblocks)
return;
hibit64 = ((u64)hibit) << 40;
r0 = key->key.r64[0];
r1 = key->key.r64[1];
r2 = key->key.r64[2];
h0 = state->h64[0];
h1 = state->h64[1];
h2 = state->h64[2];
s1 = key->precomputed_s.r64[0];
s2 = key->precomputed_s.r64[1];
do {
u64 t0, t1;
/* h += m[i] */
t0 = get_unaligned_le64(&input[0]);
t1 = get_unaligned_le64(&input[8]);
h0 += t0 & 0xfffffffffffULL;
h1 += ((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL;
h2 += (((t1 >> 24)) & 0x3ffffffffffULL) | hibit64;
/* h *= r */
d0 = (u128)h0 * r0;
d = (u128)h1 * s2;
d0 += d;
d = (u128)h2 * s1;
d0 += d;
d1 = (u128)h0 * r1;
d = (u128)h1 * r0;
d1 += d;
d = (u128)h2 * s2;
d1 += d;
d2 = (u128)h0 * r2;
d = (u128)h1 * r1;
d2 += d;
d = (u128)h2 * r0;
d2 += d;
/* (partial) h %= p */
c = (u64)(d0 >> 44);
h0 = (u64)d0 & 0xfffffffffffULL;
d1 += c;
c = (u64)(d1 >> 44);
h1 = (u64)d1 & 0xfffffffffffULL;
d2 += c;
c = (u64)(d2 >> 42);
h2 = (u64)d2 & 0x3ffffffffffULL;
h0 += c * 5;
c = h0 >> 44;
h0 = h0 & 0xfffffffffffULL;
h1 += c;
input += POLY1305_BLOCK_SIZE;
} while (--nblocks);
state->h64[0] = h0;
state->h64[1] = h1;
state->h64[2] = h2;
}
EXPORT_SYMBOL(poly1305_core_blocks);
void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4],
void *dst)
{
u8 *mac = dst;
u64 h0, h1, h2, c;
u64 g0, g1, g2;
u64 t0, t1;
/* fully carry h */
h0 = state->h64[0];
h1 = state->h64[1];
h2 = state->h64[2];
c = h1 >> 44;
h1 &= 0xfffffffffffULL;
h2 += c;
c = h2 >> 42;
h2 &= 0x3ffffffffffULL;
h0 += c * 5;
c = h0 >> 44;
h0 &= 0xfffffffffffULL;
h1 += c;
c = h1 >> 44;
h1 &= 0xfffffffffffULL;
h2 += c;
c = h2 >> 42;
h2 &= 0x3ffffffffffULL;
h0 += c * 5;
c = h0 >> 44;
h0 &= 0xfffffffffffULL;
h1 += c;
/* compute h + -p */
g0 = h0 + 5;
c = g0 >> 44;
g0 &= 0xfffffffffffULL;
g1 = h1 + c;
c = g1 >> 44;
g1 &= 0xfffffffffffULL;
g2 = h2 + c - (1ULL << 42);
/* select h if h < p, or h + -p if h >= p */
c = (g2 >> ((sizeof(u64) * 8) - 1)) - 1;
g0 &= c;
g1 &= c;
g2 &= c;
c = ~c;
h0 = (h0 & c) | g0;
h1 = (h1 & c) | g1;
h2 = (h2 & c) | g2;
if (likely(nonce)) {
/* h = (h + nonce) */
t0 = ((u64)nonce[1] << 32) | nonce[0];
t1 = ((u64)nonce[3] << 32) | nonce[2];
h0 += t0 & 0xfffffffffffULL;
c = h0 >> 44;
h0 &= 0xfffffffffffULL;
h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL) + c;
c = h1 >> 44;
h1 &= 0xfffffffffffULL;
h2 += (((t1 >> 24)) & 0x3ffffffffffULL) + c;
h2 &= 0x3ffffffffffULL;
}
/* mac = h % (2^128) */
h0 = h0 | (h1 << 44);
h1 = (h1 >> 20) | (h2 << 24);
put_unaligned_le64(h0, &mac[0]);
put_unaligned_le64(h1, &mac[8]);
}
EXPORT_SYMBOL(poly1305_core_emit);
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