cregit-Linux how code gets into the kernel

Release 4.10 tools/testing/selftests/nsfs/pidns.c


#define _GNU_SOURCE
#include <sched.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/prctl.h>
#include <sys/wait.h>


#define pr_err(fmt, ...) \
		({ \
                        fprintf(stderr, "%s:%d:" fmt ": %m\n", \
                                __func__, __LINE__, ##__VA_ARGS__); \
                        1; \
                })


#define NSIO	0xb7

#define NS_GET_USERNS   _IO(NSIO, 0x1)

#define NS_GET_PARENT   _IO(NSIO, 0x2)


#define __stack_aligned__	__attribute__((aligned(16)))

struct cr_clone_arg {
	
char stack[128] __stack_aligned__;
	
char stack_ptr[0];
};


static int child(void *args) { prctl(PR_SET_PDEATHSIG, SIGKILL); while (1) sleep(1); exit(0); }

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int main(int argc, char *argv[]) { char *ns_strs[] = {"pid", "user"}; char path[] = "/proc/0123456789/ns/pid"; struct cr_clone_arg ca; struct stat st1, st2; int ns, pns, i; pid_t pid; pid = clone(child, ca.stack_ptr, CLONE_NEWUSER | CLONE_NEWPID | SIGCHLD, NULL); if (pid < 0) return pr_err("clone"); for (i = 0; i < 2; i++) { snprintf(path, sizeof(path), "/proc/%d/ns/%s", pid, ns_strs[i]); ns = open(path, O_RDONLY); if (ns < 0) return pr_err("Unable to open %s", path); pns = ioctl(ns, NS_GET_PARENT); if (pns < 0) return pr_err("Unable to get a parent pidns"); snprintf(path, sizeof(path), "/proc/self/ns/%s", ns_strs[i]); if (stat(path, &st2)) return pr_err("Unable to stat %s", path); if (fstat(pns, &st1)) return pr_err("Unable to stat the parent pidns"); if (st1.st_ino != st2.st_ino) return pr_err("NS_GET_PARENT returned a wrong namespace"); if (ioctl(pns, NS_GET_PARENT) >= 0 || errno != EPERM) return pr_err("Don't get EPERM");; } kill(pid, SIGKILL); wait(NULL); return 0; }

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Total377100.00%1100.00%
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