1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
// Copyright 2018 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <errno.h>
#include <nss.h>
#include <pthread.h>
#include <pwd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <syslog.h>
#include <unistd.h>
#include <fstream>
#include <compat.h>
#include <oslogin_utils.h>
using oslogin_utils::BufferManager;
using oslogin_utils::MutexLock;
using oslogin_utils::NssCache;
// File paths for the nss cache file.
static const char kDefaultFilePath[] = K_DEFAULT_FILE_PATH;
static const char kDefaultBackupFilePath[] = K_DEFAULT_BACKUP_FILE_PATH;
// Local NSS Cache size. This affects the maximum number of passwd entries per
// http request.
static const uint64_t kNssCacheSize = 2048;
// Passwd buffer size. We are guaranteed that a single OS Login user will not
// exceed 32k.
static const uint64_t kPasswdBufferSize = 32768;
static NssCache nss_cache(kNssCacheSize);
static pthread_mutex_t cache_mutex = PTHREAD_MUTEX_INITIALIZER;
int main(int argc, char* argv[]) {
int error_code = 0;
// Temporary buffer to hold passwd entries before writing.
char buffer[kPasswdBufferSize];
struct passwd pwd;
// Perform the writes under a global lock.
MutexLock ml(&cache_mutex);
nss_cache.Reset();
// Check if there is a cache already.
struct stat stat_buf;
bool backup = !stat(kDefaultFilePath, &stat_buf);
if (backup) {
// Write a backup file first, in case lookup fails.
error_code = rename(kDefaultFilePath, kDefaultBackupFilePath);
if (error_code) {
openlog("nss_cache_oslogin", LOG_PID, LOG_USER);
syslog(LOG_ERR, "Could not create backup file.");
closelog();
return error_code;
}
}
std::ofstream cache_file(kDefaultFilePath);
if (cache_file.fail()) {
openlog("nss_cache_oslogin", LOG_PID, LOG_USER);
syslog(LOG_ERR, "Failed to open file %s.", kDefaultFilePath);
closelog();
return -1;
}
chown(kDefaultFilePath, 0, 0);
chmod(kDefaultFilePath, S_IRUSR | S_IWUSR | S_IROTH);
while (!nss_cache.OnLastPage() || nss_cache.HasNextPasswd()) {
BufferManager buffer_manager(buffer, kPasswdBufferSize);
if (!nss_cache.NssGetpwentHelper(&buffer_manager, &pwd, &error_code)) {
break;
}
cache_file << pwd.pw_name << ":" << pwd.pw_passwd << ":" << pwd.pw_uid
<< ":" << pwd.pw_gid << ":" << pwd.pw_gecos << ":" << pwd.pw_dir
<< ":" << pwd.pw_shell << "\n";
}
cache_file.close();
// Check for errors.
if (error_code) {
openlog("nss_cache_oslogin", LOG_PID, LOG_USER);
if (error_code == ERANGE) {
syslog(LOG_ERR, "Received unusually large passwd entry.");
} else if (error_code == EINVAL) {
syslog(LOG_ERR, "Encountered malformed passwd entry.");
} else {
syslog(LOG_ERR, "Unknown error while retrieving passwd entry.");
}
// Restore the backup.
if (backup) {
if (rename(kDefaultBackupFilePath, kDefaultFilePath)) {
syslog(LOG_ERR, "Could not restore data from backup file.");
}
}
closelog();
}
// Remove the backup file on success.
if (!error_code && backup) {
remove(kDefaultBackupFilePath);
}
return error_code;
}
|
