105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
/*
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* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "inner.h"
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/* see bearssl_block.h */
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void
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br_aes_ct64_cbcdec_init(br_aes_ct64_cbcdec_keys *ctx,
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const void *key, size_t len)
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{
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ctx->vtable = &br_aes_ct64_cbcdec_vtable;
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ctx->num_rounds = br_aes_ct64_keysched(ctx->skey, key, len);
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}
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/* see bearssl_block.h */
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void
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br_aes_ct64_cbcdec_run(const br_aes_ct64_cbcdec_keys *ctx,
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void *iv, void *data, size_t len)
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{
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unsigned char *buf;
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uint64_t sk_exp[120];
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uint32_t ivw[4];
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br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
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br_range_dec32le(ivw, 4, iv);
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buf = data;
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while (len > 0) {
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uint64_t q[8];
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uint32_t w1[16], w2[16];
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int i;
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if (len >= 64) {
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br_range_dec32le(w1, 16, buf);
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} else {
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br_range_dec32le(w1, len >> 2, buf);
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}
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for (i = 0; i < 4; i ++) {
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br_aes_ct64_interleave_in(
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&q[i], &q[i + 4], w1 + (i << 2));
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}
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br_aes_ct64_ortho(q);
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br_aes_ct64_bitslice_decrypt(ctx->num_rounds, sk_exp, q);
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br_aes_ct64_ortho(q);
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for (i = 0; i < 4; i ++) {
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br_aes_ct64_interleave_out(
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w2 + (i << 2), q[i], q[i + 4]);
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}
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for (i = 0; i < 4; i ++) {
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w2[i] ^= ivw[i];
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}
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if (len >= 64) {
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for (i = 4; i < 16; i ++) {
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w2[i] ^= w1[i - 4];
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}
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memcpy(ivw, w1 + 12, sizeof ivw);
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br_range_enc32le(buf, w2, 16);
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} else {
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int j;
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j = (int)(len >> 2);
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for (i = 4; i < j; i ++) {
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w2[i] ^= w1[i - 4];
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}
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memcpy(ivw, w1 + j - 4, sizeof ivw);
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br_range_enc32le(buf, w2, j);
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break;
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}
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buf += 64;
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len -= 64;
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}
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br_range_enc32le(iv, ivw, 4);
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}
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/* see bearssl_block.h */
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const br_block_cbcdec_class br_aes_ct64_cbcdec_vtable = {
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sizeof(br_aes_ct64_cbcdec_keys),
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16,
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4,
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(void (*)(const br_block_cbcdec_class **, const void *, size_t))
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&br_aes_ct64_cbcdec_init,
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(void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t))
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&br_aes_ct64_cbcdec_run
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};
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