60d010d18d
Merge from Widevine repo of http://go/wvgerrit/54540 Addressing comments in http://go/ag/4448747 Test: tested as part of http://go/ag/4674759 Change-Id: I29005397efcc2e982e635581cc68c8293cea6243
70 lines
1.6 KiB
C++
70 lines
1.6 KiB
C++
// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
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// source code may only be used and distributed under the Widevine Master
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// License Agreement.
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//
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// Reference implementation of OEMCrypto APIs
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//
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#include "oemcrypto_nonce_table.h"
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namespace wvoec_ref {
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void NonceTable::AddNonce(uint32_t nonce) {
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int new_slot = -1;
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int oldest_slot = -1;
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// Flush any nonces that have been checked but not flushed.
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// After flush, nonces will be either valid or invalid.
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Flush();
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for (int i = 0; i < kTableSize; ++i) {
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// Increase age of all valid nonces.
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if (kNTStateValid == state_[i]) {
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++age_[i];
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if (-1 == oldest_slot) {
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oldest_slot = i;
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} else {
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if (age_[i] > age_[oldest_slot]) {
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oldest_slot = i;
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}
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}
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} else {
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if (-1 == new_slot) {
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age_[i] = 0;
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nonces_[i] = nonce;
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state_[i] = kNTStateValid;
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new_slot = i;
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}
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}
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}
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if (-1 == new_slot) {
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// reuse oldest
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// assert (oldest_slot != -1)
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int i = oldest_slot;
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age_[i] = 0;
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nonces_[i] = nonce;
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state_[i] = kNTStateValid;
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}
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}
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bool NonceTable::CheckNonce(uint32_t nonce) {
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for (int i = 0; i < kTableSize; ++i) {
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if (kNTStateInvalid != state_[i]) {
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if (nonce == nonces_[i]) {
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state_[i] = kNTStateFlushPending;
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return true;
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}
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}
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}
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return false;
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}
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void NonceTable::Flush() {
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for (int i = 0; i < kTableSize; ++i) {
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if (kNTStateFlushPending == state_[i]) {
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state_[i] = kNTStateInvalid;
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}
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}
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}
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} // namespace wvoec_ref
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