ad92aa3575
TBR=nodir BUG=524256 Review URL: https://codereview.chromium.org/1324603002 Cr-Commit-Position: refs/heads/master@{#346335}
49 lines
1.1 KiB
Markdown
49 lines
1.1 KiB
Markdown
# Linux PID Namespace Support
|
|
|
|
The [LinuxSUIDSandbox](linux_suid_sandbox.md) currently relies on support for
|
|
the `CLONE_NEWPID` flag in Linux's
|
|
[clone() system call](http://www.kernel.org/doc/man-pages/online/pages/man2/clone.2.html).
|
|
You can check whether your system supports PID namespaces with the code below,
|
|
which must be run as root:
|
|
|
|
```c
|
|
#define _GNU_SOURCE
|
|
#include <unistd.h>
|
|
#include <sched.h>
|
|
#include <stdio.h>
|
|
#include <sys/wait.h>
|
|
|
|
#if !defined(CLONE_NEWPID)
|
|
#define CLONE_NEWPID 0x20000000
|
|
#endif
|
|
|
|
int worker(void* arg) {
|
|
const pid_t pid = getpid();
|
|
if (pid == 1) {
|
|
printf("PID namespaces are working\n");
|
|
} else {
|
|
printf("PID namespaces ARE NOT working. Child pid: %d\n", pid);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int main() {
|
|
if (getuid()) {
|
|
fprintf(stderr, "Must be run as root.\n");
|
|
return 1;
|
|
}
|
|
|
|
char stack[8192];
|
|
const pid_t child = clone(worker, stack + sizeof(stack), CLONE_NEWPID, NULL);
|
|
if (child == -1) {
|
|
perror("clone");
|
|
fprintf(stderr, "Clone failed. PID namespaces ARE NOT supported\n");
|
|
}
|
|
|
|
waitpid(child, NULL, 0);
|
|
|
|
return 0;
|
|
}
|
|
```
|