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