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
26 namespace art {
27
28 #if defined(__linux__)
29
TEST(SafeCopyTest,smoke)30 TEST(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
TEST(SafeCopyTest,alignment)76 TEST(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