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
|
/*
* Sandbox helper for CUPS.
*
* Copyright © 2020-2024 by OpenPrinting.
* Copyright © 2007-2014 by Apple Inc.
*
* Licensed under Apache License v2.0. See the file "LICENSE" for more
* information.
*
* Usage:
*
* cups-exec /path/to/profile [-u UID] [-g GID] [-n NICE] /path/to/program argv0 argv1 ... argvN
*/
/*
* Include necessary headers...
*/
#include <cups/string-private.h>
#include <cups/file.h>
#include <unistd.h>
#include <fcntl.h>
#include <grp.h>
#include <sys/stat.h>
#ifdef HAVE_SANDBOX_H
# include <sandbox.h>
# ifndef SANDBOX_NAMED_EXTERNAL
# define SANDBOX_NAMED_EXTERNAL 0x0003
# endif /* !SANDBOX_NAMED_EXTERNAL */
# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif /* HAVE_SANDBOX_H */
/*
* Local functions...
*/
static void usage(void) _CUPS_NORETURN;
/*
* 'main()' - Apply sandbox profile and execute program.
*/
int /* O - Exit status */
main(int argc, /* I - Number of command-line args */
char *argv[]) /* I - Command-line arguments */
{
int i; /* Looping var */
const char *opt; /* Current option character */
uid_t uid = getuid(); /* UID */
gid_t gid = getgid(); /* GID */
int niceval = 0; /* Nice value */
#ifdef HAVE_SANDBOX_H
char *sandbox_error = NULL; /* Sandbox error, if any */
#endif /* HAVE_SANDBOX_H */
/*
* Parse command-line...
*/
for (i = 1; i < argc; i ++)
{
if (argv[i][0] == '-')
{
for (opt = argv[i] + 1; *opt; opt ++)
{
switch (*opt)
{
case 'g' : /* -g gid */
i ++;
if (i >= argc)
usage();
gid = (gid_t)strtoul(argv[i], NULL, 10);
break;
case 'n' : /* -n nice-value */
i ++;
if (i >= argc)
usage();
niceval = atoi(argv[i]);
break;
case 'u' : /* -g gid */
i ++;
if (i >= argc)
usage();
uid = (uid_t)strtoul(argv[i], NULL, 10);
break;
default :
fprintf(stderr, "cups-exec: Unknown option '-%c'.\n", *opt);
usage();
}
}
}
else
break;
}
/*
* Check that we have enough arguments...
*/
if ((i + 3) > argc)
{
fputs("cups-exec: Insufficient arguments.\n", stderr);
usage();
}
/*
* Make sure side and back channel FDs are non-blocking...
*/
fcntl(3, F_SETFL, O_NDELAY);
fcntl(4, F_SETFL, O_NDELAY);
/*
* Change UID, GID, and nice value...
*/
if (uid)
nice(niceval);
if (!getuid())
{
if (setgid(gid))
exit(errno + 100);
# if CUPS_SNAP
if (setgroups(0, NULL))
# else
if (setgroups(1, &gid))
# endif /* CUPS_SNAP */
exit(errno + 100);
if (uid && setuid(uid))
exit(errno + 100);
}
umask(077);
#ifdef HAVE_SANDBOX_H
/*
* Run in a separate security profile...
*/
if (strcmp(argv[i], "none") &&
sandbox_init(argv[i], SANDBOX_NAMED_EXTERNAL, &sandbox_error))
{
cups_file_t *fp; /* File */
char line[1024]; /* Line from file */
unsigned linenum = 0; /* Line number in file */
fprintf(stderr, "DEBUG: sandbox_init failed: %s (%s)\n", sandbox_error,
strerror(errno));
sandbox_free_error(sandbox_error);
if ((fp = cupsFileOpen(argv[i], "r")) != NULL)
{
while (cupsFileGets(fp, line, sizeof(line)))
{
linenum ++;
fprintf(stderr, "DEBUG: %4u %s\n", linenum, line);
}
cupsFileClose(fp);
}
return (100 + EINVAL);
}
#endif /* HAVE_SANDBOX_H */
/*
* Execute the program...
*/
execv(argv[i + 1], argv + i + 2);
/*
* If we get here, execv() failed...
*/
fprintf(stderr, "DEBUG: execv failed: %s\n", strerror(errno));
return (errno + 100);
}
/*
* 'usage()' - Show program usage.
*/
static void
usage(void)
{
fputs("Usage: cups-exec [-g gid] [-n nice-value] [-u uid] /path/to/profile /path/to/program argv0 argv1 ... argvN\n", stderr);
exit(1);
}
|
