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0e23f538 TJ |
1 | /* |
2 | The software in this package is distributed under the GNU General | |
3 | Public License version 2 (with a special exception described below). | |
4 | ||
5 | A copy of GNU General Public License (GPL) is included in this distribution, | |
6 | in the file COPYING.GPL. | |
7 | ||
8 | As a special exception, if other files instantiate templates or use macros | |
9 | or inline functions from this file, or you compile this file and link it | |
10 | with other works to produce a work based on this file, this file | |
11 | does not by itself cause the resulting work to be covered | |
12 | by the GNU General Public License. | |
13 | ||
14 | However the source code for this file must still be made available | |
15 | in accordance with section (3) of the GNU General Public License. | |
16 | ||
17 | This exception does not invalidate any other reasons why a work based | |
18 | on this file might be covered by the GNU General Public License. | |
19 | */ | |
0a654ec0 TJ |
20 | /*************************************************************************** |
21 | * Copyright (C) 2008 by Intra2net AG - Thomas Jarosch * | |
0a654ec0 TJ |
22 | ***************************************************************************/ |
23 | #include <sys/types.h> | |
24 | #include <unistd.h> | |
5efd35b1 | 25 | #include <stdlib.h> |
0a654ec0 TJ |
26 | #include <pwd.h> |
27 | #include <grp.h> | |
28 | ||
29 | #include <string> | |
30 | #include <stdexcept> | |
1eb904be | 31 | #include "daemonfunc.hpp" |
6a93d84a TJ |
32 | #include "stringfunc.hxx" |
33 | #include "filefunc.hxx" | |
34 | ||
a287a306 TJ |
35 | |
36 | namespace I2n | |
6a93d84a | 37 | { |
1eb904be | 38 | namespace Daemon |
6a93d84a | 39 | { |
0a654ec0 TJ |
40 | |
41 | using namespace std; | |
42 | ||
43 | /** | |
44 | * Fork into the background. | |
45 | */ | |
6a93d84a | 46 | void daemonize() |
0a654ec0 | 47 | { |
90246b4a TJ |
48 | int pid=fork(); |
49 | ||
50 | if (pid < 0) | |
51 | { | |
52 | throw runtime_error("fork() failed"); | |
53 | } | |
54 | if (pid > 0) | |
55 | { | |
56 | // parent process | |
57 | exit (0); | |
58 | } | |
59 | // pid==0 -> child process: continue | |
0a654ec0 TJ |
60 | } |
61 | ||
62 | /** | |
09684efc | 63 | * Drop root privileges |
0a654ec0 TJ |
64 | * @param username User to become. Don't change user if empty |
65 | * @param group Group to become. Don't change group if empty | |
90246b4a TJ |
66 | * @param get_group_from_user Get group GID from user information if group is empty. |
67 | * @return true if all is fine, false otherwise | |
0a654ec0 | 68 | */ |
90246b4a TJ |
69 | bool drop_root_privileges(const std::string &username, |
70 | const std::string &group, bool get_group_from_user) | |
0a654ec0 | 71 | { |
90246b4a TJ |
72 | if (!group.empty()) |
73 | { | |
74 | Group my_group(group); | |
75 | if (!my_group.is_valid()) | |
76 | return false; | |
77 | ||
78 | if (setgid((my_group.Gid))) | |
79 | return false; | |
80 | } | |
81 | ||
82 | if (!username.empty()) | |
83 | { | |
84 | User my_user(username); | |
85 | if (!my_user.is_valid()) | |
86 | return false; | |
87 | ||
88 | if (get_group_from_user && group.empty()) | |
89 | { | |
90 | if (setgid((my_user.Gid))) | |
91 | return false; | |
92 | } | |
93 | ||
dcd37d35 | 94 | // Initialize additional groups the user is a member of |
a6238e63 | 95 | if (initgroups(username.c_str(), getgid()) == -1) |
dcd37d35 TJ |
96 | return false; |
97 | ||
90246b4a TJ |
98 | if (setuid(my_user.Uid)) |
99 | return false; | |
100 | } | |
e43beb91 TJ |
101 | |
102 | return true; | |
6a93d84a TJ |
103 | } |
104 | ||
492f4a6d PG |
105 | static const char *const EXE_DELETED_MARKER = " (deleted)"; |
106 | ||
107 | /** @brief Remove the deletion marker from a binary name, if applicable. | |
108 | * | |
109 | * @param exe Binary name as obtained from ``/proc/$PID/exe``. | |
110 | * | |
111 | * @return The input binary name with a trailing `` (deleted)`` removed. | |
112 | * | |
113 | * From proc(5): | |
114 | * | |
115 | * /proc/[pid]/exe | |
116 | * […] If the pathname has been unlinked, the symbolic link will | |
117 | * contain the string '(deleted)' appended to the original pathname. | |
118 | * | |
119 | * Which introduces an ambiguity if the path of the actual binary ends in | |
120 | * `` (deleted)``. | |
121 | */ | |
122 | static inline std::string | |
123 | strip_deleted_marker (const std::string &exe) | |
124 | { | |
125 | if (exe.size () <= sizeof (*EXE_DELETED_MARKER)) { | |
126 | /* This binary name can’t possibly contain a deleted marker. */ | |
127 | return exe; | |
128 | } | |
129 | ||
130 | const size_t found = exe.rfind (EXE_DELETED_MARKER); | |
131 | if (found == std::string::npos) { | |
132 | /* Input does not contain the deleted marker. */ | |
133 | return exe; | |
134 | } | |
135 | ||
136 | return exe.substr (0, found); | |
137 | } | |
138 | ||
6a93d84a TJ |
139 | /** |
140 | * @brief determine the pids for a given program | |
141 | * @param[in] name name (or full path) of the binary | |
142 | * @param[out] result the pids associated with the name. | |
143 | * @return @a true if the function performed without errors. | |
144 | * | |
145 | * Walk though the /proc/\<pid\>'s and search for the name. | |
146 | * | |
147 | * @note Since this function uses /proc, it's system specific. Currently: | |
148 | * Linux only! | |
149 | * | |
150 | * @todo check cmdline and stat in /proc/\<pid\> dir for the searched name. | |
151 | */ | |
152 | bool pid_of(const std::string& name, std::vector< pid_t >& result) | |
153 | { | |
90246b4a TJ |
154 | std::vector< std::string > entries; |
155 | std::vector< pid_t > fuzz1_result; | |
156 | std::vector< pid_t > fuzz2_result; | |
157 | result.clear(); | |
edd749de GE |
158 | |
159 | if (name.empty()) return false; | |
90246b4a | 160 | if (!get_dir("/proc", entries)) return false; |
edd749de | 161 | |
90246b4a TJ |
162 | for (std::vector< std::string >::const_iterator it= entries.begin(); |
163 | it != entries.end(); | |
164 | ++it) | |
165 | { | |
166 | pid_t pid; | |
167 | if (! string_to<pid_t>(*it, pid)) continue; | |
168 | std::string base_path= std::string("/proc/") + *it; | |
169 | std::string exe_path= base_path + "/exe"; | |
170 | I2n::Stat stat(exe_path, false); | |
171 | if (not stat or not stat.is_link()) continue; | |
172 | std::string real_exe= read_link(exe_path); | |
edd749de | 173 | if (!real_exe.empty()) |
90246b4a | 174 | { |
edd749de | 175 | // we got the path of the exe |
492f4a6d | 176 | if (real_exe == name || strip_deleted_marker (real_exe) == name) |
edd749de | 177 | { |
492f4a6d PG |
178 | result.push_back( pid ); |
179 | continue; | |
edd749de | 180 | } |
492f4a6d | 181 | |
edd749de GE |
182 | std::string proc_stat= read_file( base_path + "/stat"); |
183 | if (proc_stat.empty()) continue; // process vanished | |
492f4a6d | 184 | |
edd749de | 185 | //TODO some more fuzz tests here?! (cmdline, stat(us)) |
492f4a6d PG |
186 | |
187 | real_exe = basename (real_exe); | |
188 | if (real_exe == name || strip_deleted_marker (real_exe) == name) | |
edd749de | 189 | { |
492f4a6d PG |
190 | fuzz2_result.push_back(pid); |
191 | continue; | |
edd749de | 192 | } |
90246b4a | 193 | } |
edd749de | 194 | else |
90246b4a | 195 | { |
edd749de GE |
196 | // we haven't got the path of the exe |
197 | // this can happen e.g. with processes owned by other users | |
198 | // -> parse the commandline instead | |
199 | std::string cmdline = read_file(base_path + "/cmdline"); | |
200 | if (cmdline.empty()) continue; | |
201 | ||
202 | // in /proc/*/cmdline, the parameters are split by nullbytes, we only care for the first parameter | |
203 | if (cmdline.find('\0') != string::npos) | |
204 | cmdline.erase(cmdline.find('\0')); | |
205 | ||
206 | if (cmdline == name) | |
207 | { | |
208 | result.push_back( pid ); | |
209 | continue; | |
210 | } | |
211 | ||
212 | if (basename(cmdline) == name) | |
213 | { | |
214 | fuzz2_result.push_back(pid); | |
215 | continue; | |
216 | } | |
90246b4a TJ |
217 | } |
218 | } | |
219 | if (result.empty()) | |
220 | { | |
221 | result.swap(fuzz1_result); | |
222 | } | |
223 | if (result.empty()) | |
224 | { | |
225 | result.swap(fuzz2_result); | |
226 | } | |
227 | return true; | |
6a93d84a TJ |
228 | } // eo pidOf(const std::string&,std::vector< pid_t >&) |
229 | ||
230 | } | |
0a654ec0 | 231 | } |