1 /*
2 * Copyright (C) 2025 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 "../includes/common.h"
18 #include "binary_loader.h"
19
20 size_t kItems = 2;
21 size_t kSize = SIZE_MAX;
22 void* kAddress = &kItems;
23
24 typedef void* (*skia_alloc_func)(void*, unsigned long, unsigned long);
25
calloc(size_t item,size_t size)26 void* calloc(size_t item, size_t size) {
27 if (item * size == kItems * kSize) {
28 return kAddress;
29 }
30
31 // memset to imitate actual calloc() call
32 void* ptr = malloc(item * size);
33 memset(ptr, 0, item * size);
34 return ptr;
35 }
36
main(int,char * argv[])37 int main(int /* argc */, char* argv[]) {
38 // Get the path to the shared library and offset from command-line arguments
39 const char* libPath = argv[1];
40 const uintptr_t functionOffset = strtoul(argv[2], nullptr, 0) + 1;
41
42 // Get function address of 'skia_alloc_func()' from loaded library
43 BinaryLoader binaryLoader(libPath);
44 const uintptr_t functionAddress = binaryLoader.getFunctionAddress(functionOffset);
45 FAIL_CHECK(functionAddress);
46
47 // Create function pointer to 'skia_alloc_func()'
48 skia_alloc_func skia_alloc_ptr = (skia_alloc_func)functionAddress;
49
50 // Call vulnerable function. Without fix, function returns pointer from the overloaded calloc().
51 // With Fix, null pointer is returned.
52 void* result = skia_alloc_ptr(nullptr, kItems, kSize);
53 if (result == nullptr) {
54 return EXIT_SUCCESS;
55 }
56 if (result == kAddress) {
57 return EXIT_VULNERABLE;
58 }
59 return EXIT_FAILURE;
60 }
61