android_keymaster_utils.cpp revision e3e33cc8688fbf037974d1f1ae22c11b9e67d361 
1/*
2 * Copyright 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <keymaster/android_keymaster_utils.h>
18
19#include <new>
20
21namespace keymaster {
22
23// Keymaster never manages enormous buffers, so anything particularly large is bad data or the
24// result of a bug.  We arbitrarily set a 16 MiB limit.
25const size_t kMaxDupBufferSize = 16 * 1024 * 1024;
26
27uint8_t* dup_buffer(const void* buf, size_t size) {
28    if (size >= kMaxDupBufferSize)
29        return nullptr;
30    uint8_t* retval = new (std::nothrow) uint8_t[size];
31    if (retval)
32        memcpy(retval, buf, size);
33    return retval;
34}
35
36int memcmp_s(const void* p1, const void* p2, size_t length) {
37    const uint8_t* s1 = static_cast<const uint8_t*>(p1);
38    const uint8_t* s2 = static_cast<const uint8_t*>(p2);
39    uint8_t result = 0;
40    while (length-- > 0)
41        result |= *s1++ ^ *s2++;
42    return result == 0 ? 0 : 1;
43}
44
45}  // namespace keymaster
46