1 /* 2 * Copyright (c) 1999-2001 Sendmail, 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 28 #ifndef lint 29 static char id[] = "@(#)$Id: t_seteuid.c,v 8.8 2001/09/23 03:35:41 ca Exp $"; 30 #endif /* ! lint */ 31 32 #ifdef __hpux 33 # define seteuid(e) setresuid(-1, e, -1) 34 #endif /* __hpux */ 35 36 static void 37 printuids(str, r, e) 38 char *str; 39 uid_t r, e; 40 { 41 printf("%s (should be %d/%d): r/euid=%d/%d\n", str, (int) r, (int) e, 42 (int) getuid(), (int) geteuid()); 43 } 44 45 int 46 main(argc, argv) 47 int argc; 48 char **argv; 49 { 50 int fail = 0; 51 uid_t realuid = getuid(); 52 53 printuids("initial uids", realuid, 0); 54 55 if (geteuid() != 0) 56 { 57 printf("SETUP ERROR: re-run set-user-ID root\n"); 58 exit(1); 59 } 60 61 if (getuid() == 0) 62 { 63 printf("SETUP ERROR: must be run by a non-root user\n"); 64 exit(1); 65 } 66 67 if (seteuid(1) < 0) 68 printf("seteuid(1) failure\n"); 69 printuids("after seteuid(1)", realuid, 1); 70 71 if (geteuid() != 1) 72 { 73 fail++; 74 printf("MAYDAY! Wrong effective uid\n"); 75 } 76 77 /* do activity here */ 78 79 if (seteuid(0) < 0) 80 { 81 fail++; 82 printf("seteuid(0) failure\n"); 83 } 84 printuids("after seteuid(0)", realuid, 0); 85 86 if (geteuid() != 0) 87 { 88 fail++; 89 printf("MAYDAY! Wrong effective uid\n"); 90 } 91 if (getuid() != realuid) 92 { 93 fail++; 94 printf("MAYDAY! Wrong real uid\n"); 95 } 96 printf("\n"); 97 98 if (seteuid(2) < 0) 99 { 100 fail++; 101 printf("seteuid(2) failure\n"); 102 } 103 printuids("after seteuid(2)", realuid, 2); 104 105 if (geteuid() != 2) 106 { 107 fail++; 108 printf("MAYDAY! Wrong effective uid\n"); 109 } 110 111 /* do activity here */ 112 113 if (seteuid(0) < 0) 114 { 115 fail++; 116 printf("seteuid(0) failure\n"); 117 } 118 printuids("after seteuid(0)", realuid, 0); 119 120 if (geteuid() != 0) 121 { 122 fail++; 123 printf("MAYDAY! Wrong effective uid\n"); 124 } 125 if (getuid() != realuid) 126 { 127 fail++; 128 printf("MAYDAY! Wrong real uid\n"); 129 } 130 131 if (fail) 132 { 133 printf("\nThis system cannot use seteuid\n"); 134 exit(1); 135 } 136 137 printf("\nIt is safe to define USESETEUID on this system\n"); 138 exit(0); 139 } 140