1 /*
2  * Copyright (C) 2016 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 <errno.h>
18 #include <linux/fs.h>
19 #include <stdint.h>
20 #include <string.h>
21 #include <sys/mman.h>
22 #include <sys/types.h>
23 #include <unistd.h>
24 
25 #include <android-base/macros.h>
26 #include <android-base/unique_fd.h>
27 #include <cutils/ashmem.h>
28 #include <gtest/gtest.h>
29 
30 using android::base::unique_fd;
31 
TestCreateRegion(size_t size,unique_fd & fd,int prot)32 void TestCreateRegion(size_t size, unique_fd &fd, int prot) {
33     fd = unique_fd(ashmem_create_region(nullptr, size));
34     ASSERT_TRUE(fd >= 0);
35     ASSERT_TRUE(ashmem_valid(fd));
36     ASSERT_EQ(size, static_cast<size_t>(ashmem_get_size_region(fd)));
37     ASSERT_EQ(0, ashmem_set_prot_region(fd, prot));
38 }
39 
TestMmap(const unique_fd & fd,size_t size,int prot,void ** region,off_t off=0)40 void TestMmap(const unique_fd& fd, size_t size, int prot, void** region, off_t off = 0) {
41     ASSERT_TRUE(fd >= 0);
42     ASSERT_TRUE(ashmem_valid(fd));
43     *region = mmap(nullptr, size, prot, MAP_SHARED, fd, off);
44     ASSERT_NE(MAP_FAILED, *region);
45 }
46 
TestProtDenied(const unique_fd & fd,size_t size,int prot)47 void TestProtDenied(const unique_fd &fd, size_t size, int prot) {
48     ASSERT_TRUE(fd >= 0);
49     ASSERT_TRUE(ashmem_valid(fd));
50     EXPECT_EQ(MAP_FAILED, mmap(nullptr, size, prot, MAP_SHARED, fd, 0));
51 }
52 
TestProtIs(const unique_fd & fd,int prot)53 void TestProtIs(const unique_fd& fd, int prot) {
54     ASSERT_TRUE(fd >= 0);
55     ASSERT_TRUE(ashmem_valid(fd));
56     EXPECT_EQ(prot, ioctl(fd, ASHMEM_GET_PROT_MASK));
57 }
58 
FillData(uint8_t * data,size_t dataLen)59 void FillData(uint8_t* data, size_t dataLen) {
60     for (size_t i = 0; i < dataLen; i++) {
61         data[i] = i & 0xFF;
62     }
63 }
64 
TEST(AshmemTest,BasicTest)65 TEST(AshmemTest, BasicTest) {
66     constexpr size_t size = PAGE_SIZE;
67     uint8_t data[size];
68     FillData(data, size);
69 
70     unique_fd fd;
71     ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
72 
73     void *region1;
74     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ | PROT_WRITE, &region1));
75 
76     memcpy(region1, &data, size);
77     ASSERT_EQ(0, memcmp(region1, &data, size));
78 
79     EXPECT_EQ(0, munmap(region1, size));
80 
81     void *region2;
82     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ, &region2));
83     ASSERT_EQ(0, memcmp(region2, &data, size));
84     EXPECT_EQ(0, munmap(region2, size));
85 }
86 
TEST(AshmemTest,ForkTest)87 TEST(AshmemTest, ForkTest) {
88     constexpr size_t size = PAGE_SIZE;
89     uint8_t data[size];
90     FillData(data, size);
91 
92     unique_fd fd;
93     ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
94 
95     void *region1;
96     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ | PROT_WRITE, &region1));
97 
98     memcpy(region1, &data, size);
99     ASSERT_EQ(0, memcmp(region1, &data, size));
100     EXPECT_EQ(0, munmap(region1, size));
101 
102     ASSERT_EXIT(
103         {
104             if (!ashmem_valid(fd)) {
105                 _exit(3);
106             }
107             void* region2 = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
108             if (region2 == MAP_FAILED) {
109                 _exit(1);
110             }
111             if (memcmp(region2, &data, size) != 0) {
112                 _exit(2);
113             }
114             memset(region2, 0, size);
115             munmap(region2, size);
116             _exit(0);
117         },
118         ::testing::ExitedWithCode(0), "");
119 
120     memset(&data, 0, size);
121     void *region2;
122     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ | PROT_WRITE, &region2));
123     ASSERT_EQ(0, memcmp(region2, &data, size));
124     EXPECT_EQ(0, munmap(region2, size));
125 }
126 
TEST(AshmemTest,FileOperationsTest)127 TEST(AshmemTest, FileOperationsTest) {
128     unique_fd fd;
129     void* region;
130 
131     // Allocate a 4-page buffer, but leave page-sized holes on either side
132     constexpr size_t size = PAGE_SIZE * 4;
133     constexpr size_t dataSize = PAGE_SIZE * 2;
134     constexpr size_t holeSize = PAGE_SIZE;
135     ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
136     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, dataSize, PROT_READ | PROT_WRITE, &region, holeSize));
137 
138     uint8_t data[dataSize];
139     FillData(data, dataSize);
140     memcpy(region, data, dataSize);
141 
142     constexpr off_t dataStart = holeSize;
143     constexpr off_t dataEnd = dataStart + dataSize;
144 
145     // The sequence of seeks below looks something like this:
146     //
147     // [    ][data][data][    ]
148     // --^                          lseek(99, SEEK_SET)
149     //   ------^                    lseek(dataStart, SEEK_CUR)
150     // ------^                      lseek(0, SEEK_DATA)
151     //       ------------^          lseek(dataStart, SEEK_HOLE)
152     //                      ^--     lseek(-99, SEEK_END)
153     //                ^------       lseek(-dataStart, SEEK_CUR)
154     const struct {
155         // lseek() parameters
156         off_t offset;
157         int whence;
158         // Expected lseek() return value
159         off_t ret;
160     } seeks[] = {
161         {99, SEEK_SET, 99},         {dataStart, SEEK_CUR, dataStart + 99},
162         {0, SEEK_DATA, dataStart},  {dataStart, SEEK_HOLE, dataEnd},
163         {-99, SEEK_END, size - 99}, {-dataStart, SEEK_CUR, dataEnd - 99},
164     };
165     for (const auto& cfg : seeks) {
166         errno = 0;
167         ASSERT_TRUE(ashmem_valid(fd));
168         auto off = lseek(fd, cfg.offset, cfg.whence);
169         ASSERT_EQ(cfg.ret, off) << "lseek(" << cfg.offset << ", " << cfg.whence << ") failed"
170                                 << (errno ? ": " : "") << (errno ? strerror(errno) : "");
171 
172         if (off >= dataStart && off < dataEnd) {
173             off_t dataOff = off - dataStart;
174             ssize_t readSize = dataSize - dataOff;
175             uint8_t buf[readSize];
176 
177             ASSERT_EQ(readSize, TEMP_FAILURE_RETRY(read(fd, buf, readSize)));
178             EXPECT_EQ(0, memcmp(buf, data + dataOff, readSize));
179         }
180     }
181 
182     EXPECT_EQ(0, munmap(region, dataSize));
183 }
184 
TEST(AshmemTest,ProtTest)185 TEST(AshmemTest, ProtTest) {
186     unique_fd fd;
187     constexpr size_t size = PAGE_SIZE;
188     void *region;
189 
190     ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ));
191     TestProtDenied(fd, size, PROT_WRITE);
192     TestProtIs(fd, PROT_READ);
193     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ, &region));
194     EXPECT_EQ(0, munmap(region, size));
195 
196     ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_WRITE));
197     TestProtDenied(fd, size, PROT_READ);
198     TestProtIs(fd, PROT_WRITE);
199     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_WRITE, &region));
200     EXPECT_EQ(0, munmap(region, size));
201 
202     ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
203     TestProtIs(fd, PROT_READ | PROT_WRITE);
204     ASSERT_EQ(0, ashmem_set_prot_region(fd, PROT_READ));
205     errno = 0;
206     ASSERT_EQ(-1, ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE))
207         << "kernel shouldn't allow adding protection bits";
208     EXPECT_EQ(EINVAL, errno);
209     TestProtIs(fd, PROT_READ);
210     TestProtDenied(fd, size, PROT_WRITE);
211 }
212 
TEST(AshmemTest,ForkProtTest)213 TEST(AshmemTest, ForkProtTest) {
214     unique_fd fd;
215     constexpr size_t size = PAGE_SIZE;
216 
217     int protFlags[] = { PROT_READ, PROT_WRITE };
218     for (size_t i = 0; i < arraysize(protFlags); i++) {
219         ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
220         ASSERT_EXIT(
221             {
222                 if (!ashmem_valid(fd)) {
223                     _exit(3);
224                 } else if (ashmem_set_prot_region(fd, protFlags[i]) >= 0) {
225                     _exit(0);
226                 } else {
227                     _exit(1);
228                 }
229             },
230             ::testing::ExitedWithCode(0), "");
231         ASSERT_NO_FATAL_FAILURE(TestProtDenied(fd, size, protFlags[1-i]));
232     }
233 }
234 
TEST(AshmemTest,ForkMultiRegionTest)235 TEST(AshmemTest, ForkMultiRegionTest) {
236     constexpr size_t size = PAGE_SIZE;
237     uint8_t data[size];
238     FillData(data, size);
239 
240     constexpr int nRegions = 16;
241     unique_fd fd[nRegions];
242     for (int i = 0; i < nRegions; i++) {
243         ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd[i], PROT_READ | PROT_WRITE));
244         void *region;
245         ASSERT_NO_FATAL_FAILURE(TestMmap(fd[i], size, PROT_READ | PROT_WRITE, &region));
246         memcpy(region, &data, size);
247         ASSERT_EQ(0, memcmp(region, &data, size));
248         EXPECT_EQ(0, munmap(region, size));
249     }
250 
251     ASSERT_EXIT({
252         for (int i = 0; i < nRegions; i++) {
253             if (!ashmem_valid(fd[i])) {
254                 _exit(3);
255             }
256             void *region = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd[i], 0);
257             if (region == MAP_FAILED) {
258                 _exit(1);
259             }
260             if (memcmp(region, &data, size) != 0) {
261                 munmap(region, size);
262                 _exit(2);
263             }
264             memset(region, 0, size);
265             munmap(region, size);
266         }
267         _exit(0);
268     }, ::testing::ExitedWithCode(0), "");
269 
270     memset(&data, 0, size);
271     for (int i = 0; i < nRegions; i++) {
272         void *region;
273         ASSERT_NO_FATAL_FAILURE(TestMmap(fd[i], size, PROT_READ | PROT_WRITE, &region));
274         ASSERT_EQ(0, memcmp(region, &data, size));
275         EXPECT_EQ(0, munmap(region, size));
276     }
277 }
278