1/*
2 * Copyright (C) 2007 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#define TRACE_TAG SYNC
18
19#include "sysdeps.h"
20#include "file_sync_service.h"
21
22#include <dirent.h>
23#include <errno.h>
24#include <linux/xattr.h>
25#include <stdio.h>
26#include <stdlib.h>
27#include <string.h>
28#include <sys/stat.h>
29#include <sys/types.h>
30#include <sys/xattr.h>
31#include <unistd.h>
32#include <utime.h>
33
34#include <android-base/file.h>
35#include <android-base/stringprintf.h>
36#include <android-base/strings.h>
37#include <private/android_filesystem_config.h>
38#include <private/android_logger.h>
39#include <selinux/android.h>
40
41#include "adb.h"
42#include "adb_io.h"
43#include "adb_trace.h"
44#include "adb_utils.h"
45#include "security_log_tags.h"
46#include "sysdeps/errno.h"
47
48using android::base::StringPrintf;
49
50static bool should_use_fs_config(const std::string& path) {
51    // TODO: use fs_config to configure permissions on /data too.
52    return !android::base::StartsWith(path, "/data/");
53}
54
55static bool update_capabilities(const char* path, uint64_t capabilities) {
56    if (capabilities == 0) {
57        // Ensure we clean up in case the capabilities weren't 0 in the past.
58        removexattr(path, XATTR_NAME_CAPS);
59        return true;
60    }
61
62    vfs_cap_data cap_data = {};
63    cap_data.magic_etc = VFS_CAP_REVISION_2 | VFS_CAP_FLAGS_EFFECTIVE;
64    cap_data.data[0].permitted = (capabilities & 0xffffffff);
65    cap_data.data[0].inheritable = 0;
66    cap_data.data[1].permitted = (capabilities >> 32);
67    cap_data.data[1].inheritable = 0;
68    return setxattr(path, XATTR_NAME_CAPS, &cap_data, sizeof(cap_data), 0) != -1;
69}
70
71static bool secure_mkdirs(const std::string& path) {
72    uid_t uid = -1;
73    gid_t gid = -1;
74    unsigned int mode = 0775;
75    uint64_t capabilities = 0;
76
77    if (path[0] != '/') return false;
78
79    std::vector<std::string> path_components = android::base::Split(path, "/");
80    std::string partial_path;
81    for (const auto& path_component : path_components) {
82        if (partial_path.back() != OS_PATH_SEPARATOR) partial_path += OS_PATH_SEPARATOR;
83        partial_path += path_component;
84
85        if (should_use_fs_config(partial_path)) {
86            fs_config(partial_path.c_str(), 1, nullptr, &uid, &gid, &mode, &capabilities);
87        }
88        if (adb_mkdir(partial_path.c_str(), mode) == -1) {
89            if (errno != EEXIST) {
90                return false;
91            }
92        } else {
93            if (chown(partial_path.c_str(), uid, gid) == -1) return false;
94
95            // Not all filesystems support setting SELinux labels. http://b/23530370.
96            selinux_android_restorecon(partial_path.c_str(), 0);
97
98            if (!update_capabilities(partial_path.c_str(), capabilities)) return false;
99        }
100    }
101    return true;
102}
103
104static bool do_lstat_v1(int s, const char* path) {
105    syncmsg msg = {};
106    msg.stat_v1.id = ID_LSTAT_V1;
107
108    struct stat st = {};
109    lstat(path, &st);
110    msg.stat_v1.mode = st.st_mode;
111    msg.stat_v1.size = st.st_size;
112    msg.stat_v1.time = st.st_mtime;
113    return WriteFdExactly(s, &msg.stat_v1, sizeof(msg.stat_v1));
114}
115
116static bool do_stat_v2(int s, uint32_t id, const char* path) {
117    syncmsg msg = {};
118    msg.stat_v2.id = id;
119
120    decltype(&stat) stat_fn;
121    if (id == ID_STAT_V2) {
122        stat_fn = stat;
123    } else {
124        stat_fn = lstat;
125    }
126
127    struct stat st = {};
128    int rc = stat_fn(path, &st);
129    if (rc == -1) {
130        msg.stat_v2.error = errno_to_wire(errno);
131    } else {
132        msg.stat_v2.dev = st.st_dev;
133        msg.stat_v2.ino = st.st_ino;
134        msg.stat_v2.mode = st.st_mode;
135        msg.stat_v2.nlink = st.st_nlink;
136        msg.stat_v2.uid = st.st_uid;
137        msg.stat_v2.gid = st.st_gid;
138        msg.stat_v2.size = st.st_size;
139        msg.stat_v2.atime = st.st_atime;
140        msg.stat_v2.mtime = st.st_mtime;
141        msg.stat_v2.ctime = st.st_ctime;
142    }
143
144    return WriteFdExactly(s, &msg.stat_v2, sizeof(msg.stat_v2));
145}
146
147static bool do_list(int s, const char* path) {
148    dirent* de;
149
150    syncmsg msg;
151    msg.dent.id = ID_DENT;
152
153    std::unique_ptr<DIR, int(*)(DIR*)> d(opendir(path), closedir);
154    if (!d) goto done;
155
156    while ((de = readdir(d.get()))) {
157        std::string filename(StringPrintf("%s/%s", path, de->d_name));
158
159        struct stat st;
160        if (lstat(filename.c_str(), &st) == 0) {
161            size_t d_name_length = strlen(de->d_name);
162            msg.dent.mode = st.st_mode;
163            msg.dent.size = st.st_size;
164            msg.dent.time = st.st_mtime;
165            msg.dent.namelen = d_name_length;
166
167            if (!WriteFdExactly(s, &msg.dent, sizeof(msg.dent)) ||
168                    !WriteFdExactly(s, de->d_name, d_name_length)) {
169                return false;
170            }
171        }
172    }
173
174done:
175    msg.dent.id = ID_DONE;
176    msg.dent.mode = 0;
177    msg.dent.size = 0;
178    msg.dent.time = 0;
179    msg.dent.namelen = 0;
180    return WriteFdExactly(s, &msg.dent, sizeof(msg.dent));
181}
182
183// Make sure that SendFail from adb_io.cpp isn't accidentally used in this file.
184#pragma GCC poison SendFail
185
186static bool SendSyncFail(int fd, const std::string& reason) {
187    D("sync: failure: %s", reason.c_str());
188
189    syncmsg msg;
190    msg.data.id = ID_FAIL;
191    msg.data.size = reason.size();
192    return WriteFdExactly(fd, &msg.data, sizeof(msg.data)) && WriteFdExactly(fd, reason);
193}
194
195static bool SendSyncFailErrno(int fd, const std::string& reason) {
196    return SendSyncFail(fd, StringPrintf("%s: %s", reason.c_str(), strerror(errno)));
197}
198
199static bool handle_send_file(int s, const char* path, uid_t uid, gid_t gid, uint64_t capabilities,
200                             mode_t mode, std::vector<char>& buffer, bool do_unlink) {
201    syncmsg msg;
202    unsigned int timestamp = 0;
203
204    __android_log_security_bswrite(SEC_TAG_ADB_SEND_FILE, path);
205
206    int fd = adb_open_mode(path, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, mode);
207
208    if (posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE | POSIX_FADV_WILLNEED) <
209        0) {
210        D("[ Failed to fadvise: %d ]", errno);
211    }
212
213    if (fd < 0 && errno == ENOENT) {
214        if (!secure_mkdirs(android::base::Dirname(path))) {
215            SendSyncFailErrno(s, "secure_mkdirs failed");
216            goto fail;
217        }
218        fd = adb_open_mode(path, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, mode);
219    }
220    if (fd < 0 && errno == EEXIST) {
221        fd = adb_open_mode(path, O_WRONLY | O_CLOEXEC, mode);
222    }
223    if (fd < 0) {
224        SendSyncFailErrno(s, "couldn't create file");
225        goto fail;
226    } else {
227        if (fchown(fd, uid, gid) == -1) {
228            SendSyncFailErrno(s, "fchown failed");
229            goto fail;
230        }
231
232        // Not all filesystems support setting SELinux labels. http://b/23530370.
233        selinux_android_restorecon(path, 0);
234
235        // fchown clears the setuid bit - restore it if present.
236        // Ignore the result of calling fchmod. It's not supported
237        // by all filesystems, so we don't check for success. b/12441485
238        fchmod(fd, mode);
239    }
240
241    while (true) {
242        if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) goto fail;
243
244        if (msg.data.id != ID_DATA) {
245            if (msg.data.id == ID_DONE) {
246                timestamp = msg.data.size;
247                break;
248            }
249            SendSyncFail(s, "invalid data message");
250            goto abort;
251        }
252
253        if (msg.data.size > buffer.size()) {  // TODO: resize buffer?
254            SendSyncFail(s, "oversize data message");
255            goto abort;
256        }
257
258        if (!ReadFdExactly(s, &buffer[0], msg.data.size)) goto abort;
259
260        if (!WriteFdExactly(fd, &buffer[0], msg.data.size)) {
261            SendSyncFailErrno(s, "write failed");
262            goto fail;
263        }
264    }
265
266    adb_close(fd);
267
268    if (!update_capabilities(path, capabilities)) {
269        SendSyncFailErrno(s, "update_capabilities failed");
270        goto fail;
271    }
272
273    utimbuf u;
274    u.actime = timestamp;
275    u.modtime = timestamp;
276    utime(path, &u);
277
278    msg.status.id = ID_OKAY;
279    msg.status.msglen = 0;
280    return WriteFdExactly(s, &msg.status, sizeof(msg.status));
281
282fail:
283    // If there's a problem on the device, we'll send an ID_FAIL message and
284    // close the socket. Unfortunately the kernel will sometimes throw that
285    // data away if the other end keeps writing without reading (which is
286    // the case with old versions of adb). To maintain compatibility, keep
287    // reading and throwing away ID_DATA packets until the other side notices
288    // that we've reported an error.
289    while (true) {
290        if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) break;
291
292        if (msg.data.id == ID_DONE) {
293            break;
294        } else if (msg.data.id != ID_DATA) {
295            char id[5];
296            memcpy(id, &msg.data.id, sizeof(msg.data.id));
297            id[4] = '\0';
298            D("handle_send_fail received unexpected id '%s' during failure", id);
299            break;
300        }
301
302        if (msg.data.size > buffer.size()) {
303            D("handle_send_fail received oversized packet of length '%u' during failure",
304              msg.data.size);
305            break;
306        }
307
308        if (!ReadFdExactly(s, &buffer[0], msg.data.size)) break;
309    }
310
311abort:
312    if (fd >= 0) adb_close(fd);
313    if (do_unlink) adb_unlink(path);
314    return false;
315}
316
317#if defined(_WIN32)
318extern bool handle_send_link(int s, const std::string& path, std::vector<char>& buffer) __attribute__((error("no symlinks on Windows")));
319#else
320static bool handle_send_link(int s, const std::string& path, std::vector<char>& buffer) {
321    syncmsg msg;
322    unsigned int len;
323    int ret;
324
325    if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) return false;
326
327    if (msg.data.id != ID_DATA) {
328        SendSyncFail(s, "invalid data message: expected ID_DATA");
329        return false;
330    }
331
332    len = msg.data.size;
333    if (len > buffer.size()) { // TODO: resize buffer?
334        SendSyncFail(s, "oversize data message");
335        return false;
336    }
337    if (!ReadFdExactly(s, &buffer[0], len)) return false;
338
339    ret = symlink(&buffer[0], path.c_str());
340    if (ret && errno == ENOENT) {
341        if (!secure_mkdirs(android::base::Dirname(path))) {
342            SendSyncFailErrno(s, "secure_mkdirs failed");
343            return false;
344        }
345        ret = symlink(&buffer[0], path.c_str());
346    }
347    if (ret) {
348        SendSyncFailErrno(s, "symlink failed");
349        return false;
350    }
351
352    if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) return false;
353
354    if (msg.data.id == ID_DONE) {
355        msg.status.id = ID_OKAY;
356        msg.status.msglen = 0;
357        if (!WriteFdExactly(s, &msg.status, sizeof(msg.status))) return false;
358    } else {
359        SendSyncFail(s, "invalid data message: expected ID_DONE");
360        return false;
361    }
362
363    return true;
364}
365#endif
366
367static bool do_send(int s, const std::string& spec, std::vector<char>& buffer) {
368    // 'spec' is of the form "/some/path,0755". Break it up.
369    size_t comma = spec.find_last_of(',');
370    if (comma == std::string::npos) {
371        SendSyncFail(s, "missing , in ID_SEND");
372        return false;
373    }
374
375    std::string path = spec.substr(0, comma);
376
377    errno = 0;
378    mode_t mode = strtoul(spec.substr(comma + 1).c_str(), nullptr, 0);
379    if (errno != 0) {
380        SendSyncFail(s, "bad mode");
381        return false;
382    }
383
384    // Don't delete files before copying if they are not "regular" or symlinks.
385    struct stat st;
386    bool do_unlink = (lstat(path.c_str(), &st) == -1) || S_ISREG(st.st_mode) || S_ISLNK(st.st_mode);
387    if (do_unlink) {
388        adb_unlink(path.c_str());
389    }
390
391    if (S_ISLNK(mode)) {
392        return handle_send_link(s, path.c_str(), buffer);
393    }
394
395    // Copy user permission bits to "group" and "other" permissions.
396    mode &= 0777;
397    mode |= ((mode >> 3) & 0070);
398    mode |= ((mode >> 3) & 0007);
399
400    uid_t uid = -1;
401    gid_t gid = -1;
402    uint64_t capabilities = 0;
403    if (should_use_fs_config(path)) {
404        unsigned int broken_api_hack = mode;
405        fs_config(path.c_str(), 0, nullptr, &uid, &gid, &broken_api_hack, &capabilities);
406        mode = broken_api_hack;
407    }
408    return handle_send_file(s, path.c_str(), uid, gid, capabilities, mode, buffer, do_unlink);
409}
410
411static bool do_recv(int s, const char* path, std::vector<char>& buffer) {
412    __android_log_security_bswrite(SEC_TAG_ADB_RECV_FILE, path);
413
414    int fd = adb_open(path, O_RDONLY | O_CLOEXEC);
415    if (fd < 0) {
416        SendSyncFailErrno(s, "open failed");
417        return false;
418    }
419
420    if (posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE) < 0) {
421        D("[ Failed to fadvise: %d ]", errno);
422    }
423
424    syncmsg msg;
425    msg.data.id = ID_DATA;
426    while (true) {
427        int r = adb_read(fd, &buffer[0], buffer.size() - sizeof(msg.data));
428        if (r <= 0) {
429            if (r == 0) break;
430            SendSyncFailErrno(s, "read failed");
431            adb_close(fd);
432            return false;
433        }
434        msg.data.size = r;
435        if (!WriteFdExactly(s, &msg.data, sizeof(msg.data)) || !WriteFdExactly(s, &buffer[0], r)) {
436            adb_close(fd);
437            return false;
438        }
439    }
440
441    adb_close(fd);
442
443    msg.data.id = ID_DONE;
444    msg.data.size = 0;
445    return WriteFdExactly(s, &msg.data, sizeof(msg.data));
446}
447
448static const char* sync_id_to_name(uint32_t id) {
449  switch (id) {
450    case ID_LSTAT_V1:
451      return "lstat_v1";
452    case ID_LSTAT_V2:
453      return "lstat_v2";
454    case ID_STAT_V2:
455      return "stat_v2";
456    case ID_LIST:
457      return "list";
458    case ID_SEND:
459      return "send";
460    case ID_RECV:
461      return "recv";
462    case ID_QUIT:
463        return "quit";
464    default:
465        return "???";
466  }
467}
468
469static bool handle_sync_command(int fd, std::vector<char>& buffer) {
470    D("sync: waiting for request");
471
472    ATRACE_CALL();
473    SyncRequest request;
474    if (!ReadFdExactly(fd, &request, sizeof(request))) {
475        SendSyncFail(fd, "command read failure");
476        return false;
477    }
478    size_t path_length = request.path_length;
479    if (path_length > 1024) {
480        SendSyncFail(fd, "path too long");
481        return false;
482    }
483    char name[1025];
484    if (!ReadFdExactly(fd, name, path_length)) {
485        SendSyncFail(fd, "filename read failure");
486        return false;
487    }
488    name[path_length] = 0;
489
490    std::string id_name = sync_id_to_name(request.id);
491    std::string trace_name = StringPrintf("%s(%s)", id_name.c_str(), name);
492    ATRACE_NAME(trace_name.c_str());
493
494    D("sync: %s('%s')", id_name.c_str(), name);
495    switch (request.id) {
496        case ID_LSTAT_V1:
497            if (!do_lstat_v1(fd, name)) return false;
498            break;
499        case ID_LSTAT_V2:
500        case ID_STAT_V2:
501            if (!do_stat_v2(fd, request.id, name)) return false;
502            break;
503        case ID_LIST:
504            if (!do_list(fd, name)) return false;
505            break;
506        case ID_SEND:
507            if (!do_send(fd, name, buffer)) return false;
508            break;
509        case ID_RECV:
510            if (!do_recv(fd, name, buffer)) return false;
511            break;
512        case ID_QUIT:
513            return false;
514        default:
515            SendSyncFail(fd, StringPrintf("unknown command %08x", request.id));
516            return false;
517    }
518
519    return true;
520}
521
522void file_sync_service(int fd, void*) {
523    std::vector<char> buffer(SYNC_DATA_MAX);
524
525    while (handle_sync_command(fd, buffer)) {
526    }
527
528    D("sync: done");
529    adb_close(fd);
530}
531