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
|
#include <sys/types.h>
#include <err.h>
#include <grp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifndef ABUILD_GROUP
#define ABUILD_GROUP "abuild"
#endif
static const char* valid_cmds[] = {
"/bin/adduser",
"/bin/addgroup",
"/sbin/apk",
NULL
};
const char *get_command_path(const char *cmd)
{
const char *p;
int i;
for (i = 0; valid_cmds[i] != NULL; i++) {
p = strrchr(valid_cmds[i], '/') + 1;
if (strcmp(p, cmd) == 0)
return valid_cmds[i];
}
return NULL;
}
int is_in_group(gid_t group)
{
int ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
gid_t *buf = malloc(ngroups_max * sizeof(gid_t));
int ngroups, ret = 0;
int i;
if (buf == NULL) {
perror("malloc");
return 0;
}
ngroups = getgroups(ngroups_max, buf);
for (i = 0; i < ngroups; i++) {
if (buf[i] == group)
break;
}
free(buf);
return i < ngroups;
}
int main(int argc, const char *argv[])
{
struct group *grent;
const char *cmd;
const char *path;
grent = getgrnam(ABUILD_GROUP);
if (grent == NULL)
errx(1, "%s: Group not found", ABUILD_GROUP);
if (!is_in_group(grent->gr_gid))
errx(1, "Not a member of group %s\n", ABUILD_GROUP);
cmd = strrchr(argv[0], '-');
if (cmd == NULL)
errx(1, "Calling command has no '-'");
cmd++;
path = get_command_path(cmd);
if (path == NULL)
errx(1, "%s: Not a valid subcommand", cmd);
argv[0] = path;
/* set our uid to root soo bbsuid --install works */
setuid(0);
execv(path, (char * const*)argv);
return 1;
}
|
