1 /* 2 * Copyright (c) 1999-2001 Proofpoint, Inc. and its suppliers. 3 * All rights reserved. 4 * 5 * By using this file, you agree to the terms and conditions set 6 * forth in the LICENSE file which can be found at the top level of 7 * the sendmail distribution. 8 * 9 */ 10 11 /* 12 ** This program checks to see if your version of seteuid works. 13 ** Compile it, make it set-user-ID root, and run it as yourself (NOT as 14 ** root). If it won't compile or outputs any MAYDAY messages, don't 15 ** define USESETEUID in conf.h. 16 ** 17 ** NOTE: It is not sufficient to have seteuid in your library. 18 ** You must also have saved uids that function properly. 19 ** 20 ** Compilation is trivial -- just "cc t_seteuid.c". Make it set-user-ID 21 ** root and then execute it as a non-root user. 22 */ 23 24 #include <sys/types.h> 25 #include <unistd.h> 26 #include <stdio.h> 27 #include <stdlib.h> 28 29 #ifndef lint 30 static char id[] = "@(#)$Id: t_seteuid.c,v 8.9 2013-11-22 20:52:01 ca Exp $"; 31 #endif 32 33 #ifdef __hpux 34 # define seteuid(e) setresuid(-1, e, -1) 35 #endif 36 37 static void 38 printuids(str, r, e) 39 char *str; 40 uid_t r, e; 41 { 42 printf("%s (should be %d/%d): r/euid=%d/%d\n", str, (int) r, (int) e, 43 (int) getuid(), (int) geteuid()); 44 } 45 46 int 47 main(argc, argv) 48 int argc; 49 char **argv; 50 { 51 int fail = 0; 52 uid_t realuid = getuid(); 53 54 printuids("initial uids", realuid, 0); 55 56 if (geteuid() != 0) 57 { 58 printf("SETUP ERROR: re-run set-user-ID root\n"); 59 exit(1); 60 } 61 62 if (getuid() == 0) 63 { 64 printf("SETUP ERROR: must be run by a non-root user\n"); 65 exit(1); 66 } 67 68 if (seteuid(1) < 0) 69 printf("seteuid(1) failure\n"); 70 printuids("after seteuid(1)", realuid, 1); 71 72 if (geteuid() != 1) 73 { 74 fail++; 75 printf("MAYDAY! Wrong effective uid\n"); 76 } 77 78 /* do activity here */ 79 80 if (seteuid(0) < 0) 81 { 82 fail++; 83 printf("seteuid(0) failure\n"); 84 } 85 printuids("after seteuid(0)", realuid, 0); 86 87 if (geteuid() != 0) 88 { 89 fail++; 90 printf("MAYDAY! Wrong effective uid\n"); 91 } 92 if (getuid() != realuid) 93 { 94 fail++; 95 printf("MAYDAY! Wrong real uid\n"); 96 } 97 printf("\n"); 98 99 if (seteuid(2) < 0) 100 { 101 fail++; 102 printf("seteuid(2) failure\n"); 103 } 104 printuids("after seteuid(2)", realuid, 2); 105 106 if (geteuid() != 2) 107 { 108 fail++; 109 printf("MAYDAY! Wrong effective uid\n"); 110 } 111 112 /* do activity here */ 113 114 if (seteuid(0) < 0) 115 { 116 fail++; 117 printf("seteuid(0) failure\n"); 118 } 119 printuids("after seteuid(0)", realuid, 0); 120 121 if (geteuid() != 0) 122 { 123 fail++; 124 printf("MAYDAY! Wrong effective uid\n"); 125 } 126 if (getuid() != realuid) 127 { 128 fail++; 129 printf("MAYDAY! Wrong real uid\n"); 130 } 131 132 if (fail) 133 { 134 printf("\nThis system cannot use seteuid\n"); 135 exit(1); 136 } 137 138 printf("\nIt is safe to define USESETEUID on this system\n"); 139 exit(0); 140 } 141