boringssl/crypto/fipsmodule/modes/polyval.c
Adam Langley c5e9ac1cac Move AES-GCM-SIV out from SMALL and handle unaligned keys.
In order to use AES-GCM-SIV in the open-source QUIC boxer, it needs to
be moved out from OPENSSL_SMALL. (Hopefully the linker can still discard
it in the vast majority of cases.)

Additionally, the input to the key schedule function comes from outside
and may not be aligned, thus we need to use unaligned instructions to
read it.

Change-Id: I02c261fe0663d13a96c428174943c7e5ac8415a7
Reviewed-on: https://boringssl-review.googlesource.com/16824
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2017-06-01 18:45:06 +00:00

92 lines
2.9 KiB
C

/* Copyright (c) 2016, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/base.h>
#include <assert.h>
#include <string.h>
#include "internal.h"
#include "../../internal.h"
/* byte_reverse reverses the order of the bytes in |b->c|. */
static void byte_reverse(polyval_block *b) {
const uint64_t t = CRYPTO_bswap8(b->u[0]);
b->u[0] = CRYPTO_bswap8(b->u[1]);
b->u[1] = t;
}
/* reverse_and_mulX_ghash interprets the bytes |b->c| as a reversed element of
* the GHASH field, multiplies that by 'x' and serialises the result back into
* |b|, but with GHASH's backwards bit ordering. */
static void reverse_and_mulX_ghash(polyval_block *b) {
uint64_t hi = b->u[0];
uint64_t lo = b->u[1];
const crypto_word_t carry = constant_time_eq_w(hi & 1, 1);
hi >>= 1;
hi |= lo << 63;
lo >>= 1;
lo ^= ((uint64_t) constant_time_select_w(carry, 0xe1, 0)) << 56;
b->u[0] = CRYPTO_bswap8(lo);
b->u[1] = CRYPTO_bswap8(hi);
}
/* POLYVAL(H, X_1, ..., X_n) =
* ByteReverse(GHASH(mulX_GHASH(ByteReverse(H)), ByteReverse(X_1), ...,
* ByteReverse(X_n))).
*
* See https://tools.ietf.org/html/draft-irtf-cfrg-gcmsiv-02#appendix-A. */
void CRYPTO_POLYVAL_init(struct polyval_ctx *ctx, const uint8_t key[16]) {
polyval_block H;
OPENSSL_memcpy(H.c, key, 16);
reverse_and_mulX_ghash(&H);
int is_avx;
CRYPTO_ghash_init(&ctx->gmult, &ctx->ghash, &ctx->H, ctx->Htable, &is_avx,
H.c);
OPENSSL_memset(&ctx->S, 0, sizeof(ctx->S));
}
void CRYPTO_POLYVAL_update_blocks(struct polyval_ctx *ctx, const uint8_t *in,
size_t in_len) {
assert((in_len & 15) == 0);
polyval_block reversed[32];
while (in_len > 0) {
size_t todo = in_len;
if (todo > sizeof(reversed)) {
todo = sizeof(reversed);
}
OPENSSL_memcpy(reversed, in, todo);
in += todo;
in_len -= todo;
size_t blocks = todo / sizeof(polyval_block);
for (size_t i = 0; i < blocks; i++) {
byte_reverse(&reversed[i]);
}
ctx->ghash(ctx->S.u, ctx->Htable, (const uint8_t *) reversed, todo);
}
}
void CRYPTO_POLYVAL_finish(const struct polyval_ctx *ctx, uint8_t out[16]) {
polyval_block S = ctx->S;
byte_reverse(&S);
OPENSSL_memcpy(out, &S.c, sizeof(polyval_block));
}