1/*
2 * Copyright (C) 2017 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 "safe_copy.h"
18
19#include "common_runtime_test.h"
20
21#include <errno.h>
22#include <string.h>
23#include <sys/mman.h>
24#include <sys/user.h>
25
26namespace art {
27
28#if defined(__linux__)
29
30TEST(SafeCopyTest, smoke) {
31  // Map four pages, mark the second one as PROT_NONE, unmap the last one.
32  void* map = mmap(nullptr, PAGE_SIZE * 4, PROT_READ | PROT_WRITE,
33                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
34  ASSERT_NE(MAP_FAILED, map);
35  char* page1 = static_cast<char*>(map);
36  char* page2 = page1 + PAGE_SIZE;
37  char* page3 = page2 + PAGE_SIZE;
38  char* page4 = page3 + PAGE_SIZE;
39  ASSERT_EQ(0, mprotect(page1 + PAGE_SIZE, PAGE_SIZE, PROT_NONE));
40  ASSERT_EQ(0, munmap(page4, PAGE_SIZE));
41
42  page1[0] = 'a';
43  page1[PAGE_SIZE - 1] = 'z';
44
45  page3[0] = 'b';
46  page3[PAGE_SIZE - 1] = 'y';
47
48  char buf[PAGE_SIZE];
49
50  // Completely valid read.
51  memset(buf, 0xCC, sizeof(buf));
52  EXPECT_EQ(static_cast<ssize_t>(PAGE_SIZE), SafeCopy(buf, page1, PAGE_SIZE)) << strerror(errno);
53  EXPECT_EQ(0, memcmp(buf, page1, PAGE_SIZE));
54
55  // Reading into a guard page.
56  memset(buf, 0xCC, sizeof(buf));
57  EXPECT_EQ(static_cast<ssize_t>(PAGE_SIZE - 1), SafeCopy(buf, page1 + 1, PAGE_SIZE));
58  EXPECT_EQ(0, memcmp(buf, page1 + 1, PAGE_SIZE - 1));
59
60  // Reading from a guard page into a real page.
61  memset(buf, 0xCC, sizeof(buf));
62  EXPECT_EQ(0, SafeCopy(buf, page2 + PAGE_SIZE - 1, PAGE_SIZE));
63
64  // Reading off of the end of a mapping.
65  memset(buf, 0xCC, sizeof(buf));
66  EXPECT_EQ(static_cast<ssize_t>(PAGE_SIZE), SafeCopy(buf, page3, PAGE_SIZE * 2));
67  EXPECT_EQ(0, memcmp(buf, page3, PAGE_SIZE));
68
69  // Completely invalid.
70  EXPECT_EQ(0, SafeCopy(buf, page1 + PAGE_SIZE, PAGE_SIZE));
71
72  // Clean up.
73  ASSERT_EQ(0, munmap(map, PAGE_SIZE * 3));
74}
75
76TEST(SafeCopyTest, alignment) {
77  // Copy the middle of a mapping to the end of another one.
78  void* src_map = mmap(nullptr, PAGE_SIZE * 3, PROT_READ | PROT_WRITE,
79                       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
80  ASSERT_NE(MAP_FAILED, src_map);
81
82  // Add a guard page to make sure we don't write past the end of the mapping.
83  void* dst_map = mmap(nullptr, PAGE_SIZE * 4, PROT_READ | PROT_WRITE,
84                       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
85  ASSERT_NE(MAP_FAILED, dst_map);
86
87  char* src = static_cast<char*>(src_map);
88  char* dst = static_cast<char*>(dst_map);
89  ASSERT_EQ(0, mprotect(dst + 3 * PAGE_SIZE, PAGE_SIZE, PROT_NONE));
90
91  src[512] = 'a';
92  src[PAGE_SIZE * 3 - 512 - 1] = 'z';
93
94  EXPECT_EQ(static_cast<ssize_t>(PAGE_SIZE * 3 - 1024),
95            SafeCopy(dst + 1024, src + 512, PAGE_SIZE * 3 - 1024));
96  EXPECT_EQ(0, memcmp(dst + 1024, src + 512, PAGE_SIZE * 3 - 1024));
97
98  ASSERT_EQ(0, munmap(src_map, PAGE_SIZE * 3));
99  ASSERT_EQ(0, munmap(dst_map, PAGE_SIZE * 4));
100}
101
102#endif  // defined(__linux__)
103
104}  // namespace art
105