143 lines
3.9 KiB
C
143 lines
3.9 KiB
C
/*
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* Copyright (c) 2017 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 "t_inner.h"
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/* see bearssl_block.h */
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void
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br_aes_small_ctrcbc_init(br_aes_small_ctrcbc_keys *ctx,
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const void *key, size_t len)
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{
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ctx->vtable = &br_aes_small_ctrcbc_vtable;
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ctx->num_rounds = br_aes_keysched(ctx->skey, key, len);
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}
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static void
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xorbuf(void *dst, const void *src, size_t len)
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{
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unsigned char *d;
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const unsigned char *s;
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d = dst;
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s = src;
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while (len -- > 0) {
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*d ++ ^= *s ++;
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}
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}
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/* see bearssl_block.h */
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void
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br_aes_small_ctrcbc_ctr(const br_aes_small_ctrcbc_keys *ctx,
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void *ctr, void *data, size_t len)
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{
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unsigned char *buf, *bctr;
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uint32_t cc0, cc1, cc2, cc3;
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buf = data;
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bctr = ctr;
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cc3 = br_dec32be(bctr + 0);
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cc2 = br_dec32be(bctr + 4);
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cc1 = br_dec32be(bctr + 8);
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cc0 = br_dec32be(bctr + 12);
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while (len > 0) {
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unsigned char tmp[16];
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uint32_t carry;
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br_enc32be(tmp + 0, cc3);
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br_enc32be(tmp + 4, cc2);
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br_enc32be(tmp + 8, cc1);
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br_enc32be(tmp + 12, cc0);
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br_aes_small_encrypt(ctx->num_rounds, ctx->skey, tmp);
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xorbuf(buf, tmp, 16);
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buf += 16;
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len -= 16;
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cc0 ++;
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carry = (~(cc0 | -cc0)) >> 31;
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cc1 += carry;
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carry &= (~(cc1 | -cc1)) >> 31;
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cc2 += carry;
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carry &= (~(cc2 | -cc2)) >> 31;
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cc3 += carry;
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}
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br_enc32be(bctr + 0, cc3);
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br_enc32be(bctr + 4, cc2);
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br_enc32be(bctr + 8, cc1);
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br_enc32be(bctr + 12, cc0);
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}
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/* see bearssl_block.h */
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void
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br_aes_small_ctrcbc_mac(const br_aes_small_ctrcbc_keys *ctx,
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void *cbcmac, const void *data, size_t len)
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{
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const unsigned char *buf;
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buf = data;
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while (len > 0) {
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xorbuf(cbcmac, buf, 16);
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br_aes_small_encrypt(ctx->num_rounds, ctx->skey, cbcmac);
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buf += 16;
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len -= 16;
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}
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}
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/* see bearssl_block.h */
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void
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br_aes_small_ctrcbc_encrypt(const br_aes_small_ctrcbc_keys *ctx,
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void *ctr, void *cbcmac, void *data, size_t len)
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{
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br_aes_small_ctrcbc_ctr(ctx, ctr, data, len);
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br_aes_small_ctrcbc_mac(ctx, cbcmac, data, len);
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}
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/* see bearssl_block.h */
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void
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br_aes_small_ctrcbc_decrypt(const br_aes_small_ctrcbc_keys *ctx,
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void *ctr, void *cbcmac, void *data, size_t len)
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{
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br_aes_small_ctrcbc_mac(ctx, cbcmac, data, len);
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br_aes_small_ctrcbc_ctr(ctx, ctr, data, len);
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}
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/* see bearssl_block.h */
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const br_block_ctrcbc_class br_aes_small_ctrcbc_vtable PROGMEM = {
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sizeof(br_aes_small_ctrcbc_keys),
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16,
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4,
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(void (*)(const br_block_ctrcbc_class **, const void *, size_t))
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&br_aes_small_ctrcbc_init,
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(void (*)(const br_block_ctrcbc_class *const *,
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void *, void *, void *, size_t))
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&br_aes_small_ctrcbc_encrypt,
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(void (*)(const br_block_ctrcbc_class *const *,
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void *, void *, void *, size_t))
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&br_aes_small_ctrcbc_decrypt,
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(void (*)(const br_block_ctrcbc_class *const *,
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void *, void *, size_t))
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&br_aes_small_ctrcbc_ctr,
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(void (*)(const br_block_ctrcbc_class *const *,
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void *, const void *, size_t))
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&br_aes_small_ctrcbc_mac
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};
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