1 /* 2 * perm.c - check user permission for at(1) 3 * Copyright (C) 1994 Thomas Koenig 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. The name of the author(s) may not be used to endorse or promote 11 * products derived from this software without specific prior written 12 * permission. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 /* System Headers */ 27 28 #include <sys/types.h> 29 #include <errno.h> 30 #include <pwd.h> 31 #include <stddef.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <unistd.h> 36 37 /* Local headers */ 38 39 #include "privs.h" 40 #include "at.h" 41 42 /* Macros */ 43 44 #define MAXUSERID 10 45 46 /* Structures and unions */ 47 48 49 /* File scope variables */ 50 51 static char rcsid[] = "$Id$"; 52 53 /* Function declarations */ 54 55 static int check_for_user(FILE *fp,const char *name); 56 57 /* Local functions */ 58 59 static int check_for_user(FILE *fp,const char *name) 60 { 61 char *buffer; 62 size_t len; 63 int found = 0; 64 65 len = strlen(name); 66 buffer = mymalloc(len+2); 67 68 while(fgets(buffer, len+2, fp) != NULL) 69 { 70 if ((strncmp(name, buffer, len) == 0) && 71 (buffer[len] == '\n')) 72 { 73 found = 1; 74 break; 75 } 76 } 77 fclose(fp); 78 free(buffer); 79 return found; 80 } 81 /* Global functions */ 82 int check_permission() 83 { 84 FILE *fp; 85 uid_t uid = geteuid(); 86 struct passwd *pentry; 87 88 if (uid==0) 89 return 1; 90 91 if ((pentry = getpwuid(uid)) == NULL) 92 { 93 perror("Cannot access user database"); 94 exit(EXIT_FAILURE); 95 } 96 97 PRIV_START 98 99 fp=fopen(PERM_PATH "at.allow","r"); 100 101 PRIV_END 102 103 if (fp != NULL) 104 { 105 return check_for_user(fp, pentry->pw_name); 106 } 107 else 108 { 109 110 PRIV_START 111 112 fp=fopen(PERM_PATH "at.deny", "r"); 113 114 PRIV_END 115 116 if (fp != NULL) 117 { 118 return !check_for_user(fp, pentry->pw_name); 119 } 120 perror("at.deny"); 121 } 122 return 0; 123 } 124