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
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/process_util.h"
#include <ctype.h>
#include <fcntl.h>
#include <memory>
#include <unistd.h>
#include <string>
#include <sys/types.h>
#include <sys/wait.h>
#include "base/eintr_wrapper.h"
#include "base/file_util.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "nsLiteralString.h"
#include "mozilla/UniquePtr.h"
#include "prenv.h"
#include "prmem.h"
/*
* On our platforms we use an arbitrary UID.
* This is generally the UID for user `nobody', albeit it is not
* always the case.
*/
# define CHILD_UNPRIVILEGED_UID 65534
# define CHILD_UNPRIVILEGED_GID 65534
namespace {
static mozilla::EnvironmentLog gProcessLog("MOZ_PROCESS_LOG");
} // namespace
namespace base {
class EnvironmentEnvp
{
public:
EnvironmentEnvp()
: mEnvp(PR_DuplicateEnvironment()) {}
explicit EnvironmentEnvp(const environment_map &em)
{
mEnvp = (char **)PR_Malloc(sizeof(char *) * (em.size() + 1));
if (!mEnvp) {
return;
}
char **e = mEnvp;
for (environment_map::const_iterator it = em.begin();
it != em.end(); ++it, ++e) {
std::string str = it->first;
str += "=";
str += it->second;
size_t len = str.length() + 1;
*e = static_cast<char*>(PR_Malloc(len));
memcpy(*e, str.c_str(), len);
}
*e = NULL;
}
~EnvironmentEnvp()
{
if (!mEnvp) {
return;
}
for (char **e = mEnvp; *e; ++e) {
PR_Free(*e);
}
PR_Free(mEnvp);
}
char * const *AsEnvp() { return mEnvp; }
void ToMap(environment_map &em)
{
if (!mEnvp) {
return;
}
em.clear();
for (char **e = mEnvp; *e; ++e) {
const char *eq;
if ((eq = strchr(*e, '=')) != NULL) {
std::string varname(*e, eq - *e);
em[varname.c_str()] = &eq[1];
}
}
}
private:
char **mEnvp;
};
class Environment : public environment_map
{
public:
Environment()
{
EnvironmentEnvp envp;
envp.ToMap(*this);
}
char * const *AsEnvp() {
mEnvp.reset(new EnvironmentEnvp(*this));
return mEnvp->AsEnvp();
}
void Merge(const environment_map &em)
{
for (const_iterator it = em.begin(); it != em.end(); ++it) {
(*this)[it->first] = it->second;
}
}
private:
std::auto_ptr<EnvironmentEnvp> mEnvp;
};
bool LaunchApp(const std::vector<std::string>& argv,
const file_handle_mapping_vector& fds_to_remap,
bool wait, ProcessHandle* process_handle) {
return LaunchApp(argv, fds_to_remap, environment_map(),
wait, process_handle);
}
bool LaunchApp(const std::vector<std::string>& argv,
const file_handle_mapping_vector& fds_to_remap,
const environment_map& env_vars_to_set,
bool wait, ProcessHandle* process_handle,
ProcessArchitecture arch) {
return LaunchApp(argv, fds_to_remap, env_vars_to_set,
PRIVILEGES_INHERIT,
wait, process_handle);
}
bool LaunchApp(const std::vector<std::string>& argv,
const file_handle_mapping_vector& fds_to_remap,
const environment_map& env_vars_to_set,
ChildPrivileges privs,
bool wait, ProcessHandle* process_handle,
ProcessArchitecture arch) {
mozilla::UniquePtr<char*[]> argv_cstr(new char*[argv.size() + 1]);
// Illegal to allocate memory after fork and before execvp
InjectiveMultimap fd_shuffle1, fd_shuffle2;
fd_shuffle1.reserve(fds_to_remap.size());
fd_shuffle2.reserve(fds_to_remap.size());
Environment env;
env.Merge(env_vars_to_set);
char * const *envp = env.AsEnvp();
if (!envp) {
DLOG(ERROR) << "FAILED to duplicate environment for: " << argv_cstr[0];
return false;
}
pid_t pid = fork();
if (pid < 0)
return false;
if (pid == 0) {
for (file_handle_mapping_vector::const_iterator
it = fds_to_remap.begin(); it != fds_to_remap.end(); ++it) {
fd_shuffle1.push_back(InjectionArc(it->first, it->second, false));
fd_shuffle2.push_back(InjectionArc(it->first, it->second, false));
}
if (!ShuffleFileDescriptors(&fd_shuffle1))
_exit(127);
CloseSuperfluousFds(fd_shuffle2);
for (size_t i = 0; i < argv.size(); i++)
argv_cstr[i] = const_cast<char*>(argv[i].c_str());
argv_cstr[argv.size()] = NULL;
SetCurrentProcessPrivileges(privs);
execve(argv_cstr[0], argv_cstr.get(), envp);
// if we get here, we're in serious trouble and should complain loudly
// NOTE: This is async signal unsafe; it could deadlock instead. (But
// only on debug builds; otherwise it's a signal-safe no-op.)
DLOG(ERROR) << "FAILED TO exec() CHILD PROCESS, path: " << argv_cstr[0];
_exit(127);
} else {
gProcessLog.print("==> process %d launched child process %d\n",
GetCurrentProcId(), pid);
if (wait)
HANDLE_EINTR(waitpid(pid, 0, 0));
if (process_handle)
*process_handle = pid;
}
return true;
}
bool LaunchApp(const CommandLine& cl,
bool wait, bool start_hidden,
ProcessHandle* process_handle) {
file_handle_mapping_vector no_files;
return LaunchApp(cl.argv(), no_files, wait, process_handle);
}
void SetCurrentProcessPrivileges(ChildPrivileges privs) {
if (privs == PRIVILEGES_INHERIT) {
return;
}
gid_t gid = CHILD_UNPRIVILEGED_GID;
uid_t uid = CHILD_UNPRIVILEGED_UID;
if (setgid(gid) != 0) {
DLOG(ERROR) << "FAILED TO setgid() CHILD PROCESS";
_exit(127);
}
if (setuid(uid) != 0) {
DLOG(ERROR) << "FAILED TO setuid() CHILD PROCESS";
_exit(127);
}
if (chdir("/") != 0)
gProcessLog.print("==> could not chdir()\n");
}
} // namespace base
|
