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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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186 lines
3.8 KiB
C
186 lines
3.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0 OR MIT
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*
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* This is based in part on Andrew Moon's poly1305-donna, which is in the
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* public domain.
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*/
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#include <linux/kernel.h>
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#include <asm/unaligned.h>
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#include <crypto/internal/poly1305.h>
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typedef __uint128_t u128;
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void poly1305_core_setkey(struct poly1305_core_key *key, const u8 raw_key[16])
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{
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u64 t0, t1;
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/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
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t0 = get_unaligned_le64(&raw_key[0]);
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t1 = get_unaligned_le64(&raw_key[8]);
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key->key.r64[0] = t0 & 0xffc0fffffffULL;
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key->key.r64[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffffULL;
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key->key.r64[2] = ((t1 >> 24)) & 0x00ffffffc0fULL;
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/* s = 20*r */
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key->precomputed_s.r64[0] = key->key.r64[1] * 20;
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key->precomputed_s.r64[1] = key->key.r64[2] * 20;
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}
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EXPORT_SYMBOL(poly1305_core_setkey);
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void poly1305_core_blocks(struct poly1305_state *state,
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const struct poly1305_core_key *key, const void *src,
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unsigned int nblocks, u32 hibit)
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{
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const u8 *input = src;
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u64 hibit64;
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u64 r0, r1, r2;
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u64 s1, s2;
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u64 h0, h1, h2;
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u64 c;
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u128 d0, d1, d2, d;
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if (!nblocks)
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return;
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hibit64 = ((u64)hibit) << 40;
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r0 = key->key.r64[0];
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r1 = key->key.r64[1];
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r2 = key->key.r64[2];
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h0 = state->h64[0];
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h1 = state->h64[1];
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h2 = state->h64[2];
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s1 = key->precomputed_s.r64[0];
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s2 = key->precomputed_s.r64[1];
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do {
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u64 t0, t1;
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/* h += m[i] */
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t0 = get_unaligned_le64(&input[0]);
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t1 = get_unaligned_le64(&input[8]);
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h0 += t0 & 0xfffffffffffULL;
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h1 += ((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL;
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h2 += (((t1 >> 24)) & 0x3ffffffffffULL) | hibit64;
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/* h *= r */
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d0 = (u128)h0 * r0;
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d = (u128)h1 * s2;
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d0 += d;
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d = (u128)h2 * s1;
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d0 += d;
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d1 = (u128)h0 * r1;
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d = (u128)h1 * r0;
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d1 += d;
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d = (u128)h2 * s2;
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d1 += d;
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d2 = (u128)h0 * r2;
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d = (u128)h1 * r1;
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d2 += d;
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d = (u128)h2 * r0;
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d2 += d;
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/* (partial) h %= p */
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c = (u64)(d0 >> 44);
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h0 = (u64)d0 & 0xfffffffffffULL;
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d1 += c;
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c = (u64)(d1 >> 44);
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h1 = (u64)d1 & 0xfffffffffffULL;
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d2 += c;
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c = (u64)(d2 >> 42);
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h2 = (u64)d2 & 0x3ffffffffffULL;
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h0 += c * 5;
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c = h0 >> 44;
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h0 = h0 & 0xfffffffffffULL;
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h1 += c;
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input += POLY1305_BLOCK_SIZE;
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} while (--nblocks);
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state->h64[0] = h0;
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state->h64[1] = h1;
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state->h64[2] = h2;
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}
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EXPORT_SYMBOL(poly1305_core_blocks);
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void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4],
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void *dst)
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{
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u8 *mac = dst;
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u64 h0, h1, h2, c;
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u64 g0, g1, g2;
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u64 t0, t1;
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/* fully carry h */
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h0 = state->h64[0];
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h1 = state->h64[1];
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h2 = state->h64[2];
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c = h1 >> 44;
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h1 &= 0xfffffffffffULL;
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h2 += c;
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c = h2 >> 42;
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h2 &= 0x3ffffffffffULL;
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h0 += c * 5;
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c = h0 >> 44;
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h0 &= 0xfffffffffffULL;
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h1 += c;
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c = h1 >> 44;
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h1 &= 0xfffffffffffULL;
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h2 += c;
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c = h2 >> 42;
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h2 &= 0x3ffffffffffULL;
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h0 += c * 5;
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c = h0 >> 44;
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h0 &= 0xfffffffffffULL;
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h1 += c;
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/* compute h + -p */
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g0 = h0 + 5;
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c = g0 >> 44;
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g0 &= 0xfffffffffffULL;
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g1 = h1 + c;
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c = g1 >> 44;
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g1 &= 0xfffffffffffULL;
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g2 = h2 + c - (1ULL << 42);
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/* select h if h < p, or h + -p if h >= p */
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c = (g2 >> ((sizeof(u64) * 8) - 1)) - 1;
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g0 &= c;
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g1 &= c;
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g2 &= c;
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c = ~c;
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h0 = (h0 & c) | g0;
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h1 = (h1 & c) | g1;
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h2 = (h2 & c) | g2;
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if (likely(nonce)) {
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/* h = (h + nonce) */
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t0 = ((u64)nonce[1] << 32) | nonce[0];
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t1 = ((u64)nonce[3] << 32) | nonce[2];
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h0 += t0 & 0xfffffffffffULL;
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c = h0 >> 44;
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h0 &= 0xfffffffffffULL;
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h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL) + c;
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c = h1 >> 44;
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h1 &= 0xfffffffffffULL;
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h2 += (((t1 >> 24)) & 0x3ffffffffffULL) + c;
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h2 &= 0x3ffffffffffULL;
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}
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/* mac = h % (2^128) */
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h0 = h0 | (h1 << 44);
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h1 = (h1 >> 20) | (h2 << 24);
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put_unaligned_le64(h0, &mac[0]);
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put_unaligned_le64(h1, &mac[8]);
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}
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EXPORT_SYMBOL(poly1305_core_emit);
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