cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

setns-sysvipc.c (2954B)

      1/*
      2 * Copyright © 2019 Alexey Dobriyan <adobriyan@gmail.com>
      3 *
      4 * Permission to use, copy, modify, and distribute this software for any
      5 * purpose with or without fee is hereby granted, provided that the above
      6 * copyright notice and this permission notice appear in all copies.
      7 *
      8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     15 */
     16/*
     17 * Test that setns(CLONE_NEWIPC) points to new /proc/sysvipc content even
     18 * if old one is in dcache.
     19 */
     20#undef NDEBUG
     21#include <assert.h>
     22#include <errno.h>
     23#include <stdio.h>
     24#include <sched.h>
     25#include <signal.h>
     26#include <stdlib.h>
     27#include <string.h>
     28#include <unistd.h>
     29#include <sys/types.h>
     30#include <sys/stat.h>
     31#include <fcntl.h>
     32#include <sys/ipc.h>
     33#include <sys/shm.h>
     34
     35static pid_t pid = -1;
     36
     37static void f(void)
     38{
     39	if (pid > 0) {
     40		kill(pid, SIGTERM);
     41	}
     42}
     43
     44int main(void)
     45{
     46	int fd[2];
     47	char _ = 0;
     48	int nsfd;
     49
     50	atexit(f);
     51
     52	/* Check for priviledges and syscall availability straight away. */
     53	if (unshare(CLONE_NEWIPC) == -1) {
     54		if (errno == ENOSYS || errno == EPERM) {
     55			return 4;
     56		}
     57		return 1;
     58	}
     59	/* Distinguisher between two otherwise empty IPC namespaces. */
     60	if (shmget(IPC_PRIVATE, 1, IPC_CREAT) == -1) {
     61		return 1;
     62	}
     63
     64	if (pipe(fd) == -1) {
     65		return 1;
     66	}
     67
     68	pid = fork();
     69	if (pid == -1) {
     70		return 1;
     71	}
     72
     73	if (pid == 0) {
     74		if (unshare(CLONE_NEWIPC) == -1) {
     75			return 1;
     76		}
     77
     78		if (write(fd[1], &_, 1) != 1) {
     79			return 1;
     80		}
     81
     82		pause();
     83
     84		return 0;
     85	}
     86
     87	if (read(fd[0], &_, 1) != 1) {
     88		return 1;
     89	}
     90
     91	{
     92		char buf[64];
     93		snprintf(buf, sizeof(buf), "/proc/%u/ns/ipc", pid);
     94		nsfd = open(buf, O_RDONLY);
     95		if (nsfd == -1) {
     96			return 1;
     97		}
     98	}
     99
    100	/* Reliably pin dentry into dcache. */
    101	(void)open("/proc/sysvipc/shm", O_RDONLY);
    102
    103	if (setns(nsfd, CLONE_NEWIPC) == -1) {
    104		return 1;
    105	}
    106
    107	kill(pid, SIGTERM);
    108	pid = 0;
    109
    110	{
    111		char buf[4096];
    112		ssize_t rv;
    113		int fd;
    114
    115		fd = open("/proc/sysvipc/shm", O_RDONLY);
    116		if (fd == -1) {
    117			return 1;
    118		}
    119
    120#define S32 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n"
    121#define S64 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n"
    122		rv = read(fd, buf, sizeof(buf));
    123		if (rv == strlen(S32)) {
    124			assert(memcmp(buf, S32, strlen(S32)) == 0);
    125		} else if (rv == strlen(S64)) {
    126			assert(memcmp(buf, S64, strlen(S64)) == 0);
    127		} else {
    128			assert(0);
    129		}
    130	}
    131
    132	return 0;
    133}