1/* 2 * Copyright (c) 2014-2015 Dmitry V. Levin <ldv@altlinux.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28#ifdef HAVE_CONFIG_H 29# include "config.h" 30#endif 31#include <assert.h> 32#include <stdlib.h> 33#include <unistd.h> 34#include <fcntl.h> 35#include <sys/syscall.h> 36 37int 38main(void) 39{ 40#if (defined __NR_getuid || defined __NR_getxuid) \ 41 && defined(__NR_setuid) \ 42 && defined(__NR_getresuid) \ 43 && defined(__NR_setreuid) \ 44 && defined(__NR_setresuid) \ 45 && defined(__NR_fchown) \ 46 && defined(__NR_getgroups) 47 int uid; 48 int size; 49 int *list = 0; 50 51#ifndef __NR_getuid 52# define __NR_getuid __NR_getxuid 53#endif 54 uid = syscall(__NR_getuid); 55 56 (void) close(0); 57 if (open("/proc/sys/kernel/overflowuid", O_RDONLY) == 0) { 58 /* we trust the kernel */ 59 char buf[sizeof(int)*3]; 60 int n = read(0, buf, sizeof(buf) - 1); 61 if (n) { 62 buf[n] = '\0'; 63 n = atoi(buf); 64 if (uid == n) 65 return 77; 66 } 67 (void) close(0); 68 } 69 70 assert(syscall(__NR_setuid, uid) == 0); 71 { 72 /* 73 * uids returned by getresuid should be ignored 74 * to avoid 16bit vs 32bit issues. 75 */ 76 int r, e, s; 77 assert(syscall(__NR_getresuid, &r, &e, &s) == 0); 78 } 79 assert(syscall(__NR_setreuid, -1, -1L) == 0); 80 assert(syscall(__NR_setresuid, uid, -1, -1L) == 0); 81 assert(syscall(__NR_fchown, 1, -1, -1L) == 0); 82 assert((size = syscall(__NR_getgroups, 0, list)) >= 0); 83 assert(list = calloc(size + 1, sizeof(*list))); 84 assert(syscall(__NR_getgroups, size, list) == size); 85 return 0; 86#else 87 return 77; 88#endif 89} 90