1 /*
2 * Copyright (C) 2015 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 <memory>
18 #include <string>
19 #include <vector>
20
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <linux/fiemap.h>
24 #include <linux/fs.h>
25 #include <mntent.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <sys/stat.h>
29 #include <sys/types.h>
30
31 #include <android-base/logging.h>
32 #include <android-base/unique_fd.h>
33
34 #include "FileDeviceUtils.h"
35
36 namespace {
37
38 struct Options {
39 std::vector<std::string> targets;
40 bool unlink{true};
41 };
42
43 constexpr uint32_t max_extents = 32;
44
45 bool read_command_line(int argc, const char* const argv[], Options& options);
46 void usage(const char* progname);
47 bool secdiscard_path(const std::string& path);
48 bool check_fiemap(const struct fiemap& fiemap, const std::string& path);
49 bool overwrite_with_zeros(int fd, off64_t start, off64_t length);
50
51 } // namespace
52
53 #ifndef F2FS_IOCTL_MAGIC
54 #define F2FS_IOCTL_MAGIC 0xf5
55 #endif
56
57 // F2FS-specific ioctl
58 // It requires the below kernel commit merged in v5.9-rc1.
59 // 9af846486d78 ("f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl")
60 // In android12-5.4,
61 // 7fc27297c44d ("Merge remote-tracking branch 'aosp/upstream-f2fs-stable-linux-5.4.y'
62 // into android12-5.4")
63 #ifndef F2FS_IOC_SEC_TRIM_FILE
64 struct f2fs_sectrim_range {
65 __u64 start;
66 __u64 len;
67 __u64 flags;
68 };
69 #define F2FS_IOC_SEC_TRIM_FILE _IOW(F2FS_IOCTL_MAGIC, 20, struct f2fs_sectrim_range)
70 #define F2FS_TRIM_FILE_DISCARD 0x1
71 #define F2FS_TRIM_FILE_ZEROOUT 0x2
72 #endif
73
main(int argc,const char * const argv[])74 int main(int argc, const char* const argv[]) {
75 android::base::InitLogging(const_cast<char**>(argv));
76 Options options;
77 if (!read_command_line(argc, argv, options)) {
78 usage(argv[0]);
79 return -1;
80 }
81
82 for (auto const& target : options.targets) {
83 // F2FS-specific ioctl
84 // It requires the below kernel commit merged in v4.16-rc1.
85 // 1ad71a27124c ("f2fs: add an ioctl to disable GC for specific file")
86 // In android-4.4,
87 // 56ee1e817908 ("f2fs: updates on v4.16-rc1")
88 // In android-4.9,
89 // 2f17e34672a8 ("f2fs: updates on v4.16-rc1")
90 // In android-4.14,
91 // ce767d9a55bc ("f2fs: updates on v4.16-rc1")
92 #ifndef F2FS_IOC_SET_PIN_FILE
93 #define F2FS_IOC_SET_PIN_FILE _IOW(F2FS_IOCTL_MAGIC, 13, __u32)
94 #define F2FS_IOC_GET_PIN_FILE _IOR(F2FS_IOCTL_MAGIC, 14, __u32)
95 #endif
96 android::base::unique_fd fd(
97 TEMP_FAILURE_RETRY(open(target.c_str(), O_WRONLY | O_CLOEXEC, 0)));
98 if (fd == -1) {
99 LOG(ERROR) << "Secure discard open failed for: " << target;
100 continue;
101 }
102 __u32 set = 1;
103 ioctl(fd, F2FS_IOC_SET_PIN_FILE, &set);
104
105 LOG(DEBUG) << "Securely discarding '" << target << "' unlink=" << options.unlink;
106 struct f2fs_sectrim_range secRange;
107 secRange.start = 0;
108 secRange.len = -1; // until end of file
109 secRange.flags = F2FS_TRIM_FILE_DISCARD | F2FS_TRIM_FILE_ZEROOUT;
110 /*
111 * F2FS_IOC_SEC_TRIM_FILE is only supported by F2FS.
112 * 1. If device supports secure discard, it sends secure discard command on the file.
113 * 2. Otherwise, it sends discard command on the file.
114 * 3. Lastly, it overwrites zero data on it.
115 */
116 int ret = ioctl(fd, F2FS_IOC_SEC_TRIM_FILE, &secRange);
117 if (ret != 0) {
118 if (errno == EOPNOTSUPP) {
119 // If device doesn't support any type of discard, just overwrite zero data.
120 secRange.flags = F2FS_TRIM_FILE_ZEROOUT;
121 ret = ioctl(fd, F2FS_IOC_SEC_TRIM_FILE, &secRange);
122 }
123 if (ret != 0 && errno != ENOTTY) {
124 PLOG(WARNING) << "F2FS_IOC_SEC_TRIM_FILE failed on " << target;
125 }
126 }
127 if (ret != 0) {
128 if (!secdiscard_path(target)) {
129 LOG(ERROR) << "Secure discard failed for: " << target;
130 }
131 }
132 if (options.unlink) {
133 if (unlink(target.c_str()) != 0 && errno != ENOENT) {
134 PLOG(ERROR) << "Unable to unlink: " << target;
135 }
136 }
137 set = 0;
138 ioctl(fd, F2FS_IOC_SET_PIN_FILE, &set);
139 }
140 return 0;
141 }
142
143 namespace {
144
read_command_line(int argc,const char * const argv[],Options & options)145 bool read_command_line(int argc, const char* const argv[], Options& options) {
146 for (int i = 1; i < argc; i++) {
147 if (!strcmp("--no-unlink", argv[i])) {
148 options.unlink = false;
149 } else if (!strcmp("--", argv[i])) {
150 for (int j = i + 1; j < argc; j++) {
151 if (argv[j][0] != '/') return false; // Must be absolute path
152 options.targets.emplace_back(argv[j]);
153 }
154 return options.targets.size() > 0;
155 } else {
156 return false; // Unknown option
157 }
158 }
159 return false; // "--" not found
160 }
161
usage(const char * progname)162 void usage(const char* progname) {
163 fprintf(stderr, "Usage: %s [--no-unlink] -- <absolute path> ...\n", progname);
164 }
165
166 // BLKSECDISCARD all content in "path", if it's small enough.
secdiscard_path(const std::string & path)167 bool secdiscard_path(const std::string& path) {
168 auto fiemap = android::vold::PathFiemap(path, max_extents);
169 if (!fiemap || !check_fiemap(*fiemap, path)) {
170 return false;
171 }
172 auto block_device = android::vold::BlockDeviceForPath(path);
173 if (block_device.empty()) {
174 return false;
175 }
176 android::base::unique_fd fs_fd(
177 TEMP_FAILURE_RETRY(open(block_device.c_str(), O_RDWR | O_LARGEFILE | O_CLOEXEC, 0)));
178 if (fs_fd == -1) {
179 PLOG(ERROR) << "Failed to open device " << block_device;
180 return false;
181 }
182 for (uint32_t i = 0; i < fiemap->fm_mapped_extents; i++) {
183 uint64_t range[2];
184 range[0] = fiemap->fm_extents[i].fe_physical;
185 range[1] = fiemap->fm_extents[i].fe_length;
186 if (ioctl(fs_fd.get(), BLKSECDISCARD, range) == -1) {
187 // Use zero overwrite as a fallback for BLKSECDISCARD
188 if (!overwrite_with_zeros(fs_fd.get(), range[0], range[1])) return false;
189 }
190 }
191 // Should wait for overwrites completion. Otherwise after unlink(),
192 // filesystem can allocate these blocks and IO can be reordered, resulting
193 // in making zero blocks to filesystem blocks.
194 fsync(fs_fd.get());
195 return true;
196 }
197
198 // Ensure that the FIEMAP covers the file and is OK to discard
check_fiemap(const struct fiemap & fiemap,const std::string & path)199 bool check_fiemap(const struct fiemap& fiemap, const std::string& path) {
200 auto mapped = fiemap.fm_mapped_extents;
201 if (!(fiemap.fm_extents[mapped - 1].fe_flags & FIEMAP_EXTENT_LAST)) {
202 LOG(ERROR) << "Extent " << mapped - 1 << " was not the last in " << path;
203 return false;
204 }
205 for (uint32_t i = 0; i < mapped; i++) {
206 auto flags = fiemap.fm_extents[i].fe_flags;
207 if (flags & (FIEMAP_EXTENT_UNKNOWN | FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_NOT_ALIGNED)) {
208 LOG(ERROR) << "Extent " << i << " has unexpected flags " << flags << ": " << path;
209 return false;
210 }
211 }
212 return true;
213 }
214
overwrite_with_zeros(int fd,off64_t start,off64_t length)215 bool overwrite_with_zeros(int fd, off64_t start, off64_t length) {
216 if (lseek64(fd, start, SEEK_SET) != start) {
217 PLOG(ERROR) << "Seek failed for zero overwrite";
218 return false;
219 }
220 char buf[BUFSIZ];
221 memset(buf, 0, sizeof(buf));
222 while (length > 0) {
223 size_t wlen = static_cast<size_t>(std::min(static_cast<off64_t>(sizeof(buf)), length));
224 auto written = write(fd, buf, wlen);
225 if (written < 1) {
226 PLOG(ERROR) << "Write of zeroes failed";
227 return false;
228 }
229 length -= written;
230 }
231 return true;
232 }
233
234 } // namespace
235