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
|
/* Try to change effective UID. */
#define _GNU_SOURCE
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#define NOBODY 65534
#define NOBODY2 65533
int main(int argc, char ** argv)
{
// target UID is nobody, unless we're already nobody
uid_t start = geteuid();
uid_t target = start != NOBODY ? NOBODY : NOBODY2;
int result;
fprintf(stderr, "current EUID=%u, attempting EUID=%u\n", start, target);
result = seteuid(target);
// setuid(2) fails with EINVAL in user namespaces and EPERM if not root.
if (result == 0) {
printf("RISK\tsetuid(2) succeeded for EUID=%u\n", target);
return 1;
} else if (errno == EINVAL) {
printf("SAFE\tsetuid(2) failed as expected with EINVAL\n");
return 0;
}
printf("ERROR\tsetuid(2) failed unexpectedly with errno=%d\n", errno);
return 1;
}
|
