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
|
/*
* Copyright (C) 2014-2018 Firejail Authors
*
* This file is part of firejail project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
//
// Firejail access database inplementation
//
// The database is a simple list of users allowed to run firejail SUID executable
// It is usually stored in /etc/firejail/firejail.users
// One username per line in the file
#include "../include/common.h"
#include <sys/types.h>
#include <pwd.h>
#define MAXBUF 4098
static inline char *get_fname(void) {
char *fname;
if (asprintf(&fname, "%s/firejail.users", SYSCONFDIR) == -1)
errExit("asprintf");
return fname;
}
// returns 1 if the user is found in the database or if the database was not created
int firejail_user_check(const char *name) {
assert(name);
// root allowed by default
if (strcmp(name, "root") == 0)
return 1;
// user nobody disabled by default
if (strcmp(name, "nobody") == 0) {
fprintf(stderr, "Error: user nobody is not allowed to run the sandbox\n");
exit(1);
}
// check file existence
char *fname = get_fname();
if (access(fname, F_OK)) {
free(fname);
return 1; // assume the user doesn't care about access checking
}
FILE *fp = fopen(fname, "r");
free(fname);
if (!fp)
return 0;
char buf[MAXBUF];
while (fgets(buf, MAXBUF, fp)) {
// lines starting with # are comments
if (*buf == '#')
continue;
// remove \n
char *ptr = strchr(buf, '\n');
if (ptr)
*ptr = '\0';
// compare
if (strcmp(buf, name) == 0) {
fclose(fp);
return 1;
}
}
fclose(fp);
return 0;
}
// add a user to the database
void firejail_user_add(const char *name) {
assert(name);
// is this a real user?
struct passwd *pw = getpwnam(name);
if (!pw) {
fprintf(stderr, "Error: user %s not found on this system.\n", name);
return;
}
// check the user is not already in the database
char *fname = get_fname();
assert(fname);
if (access(fname, F_OK) == 0) {
if (firejail_user_check(name)) {
printf("User %s already in the database\n", name);
return;
}
}
printf("%s created\n", fname);
FILE *fp = fopen(fname, "a+");
if (!fp) {
fprintf(stderr, "Error: cannot open %s\n", fname);
perror("fopen");
free(fname);
return;
}
free(fname);
fprintf(fp, "%s\n", name);
fclose(fp);
}
|
