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 * $FreeBSD: src/usr.bin/at/perm.c,v 1.9.2.1 2001/08/02 00:55:58 obrien Exp $ 26 * $DragonFly: src/usr.bin/at/perm.c,v 1.4 2004/09/20 13:11:54 joerg Exp $ 27 */ 28 29 /* System Headers */ 30 31 #include <sys/types.h> 32 #include <err.h> 33 #include <errno.h> 34 #include <pwd.h> 35 #include <stddef.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 41 /* Local headers */ 42 43 #include "perm.h" 44 #include "privs.h" 45 #include "at.h" 46 47 /* Macros */ 48 49 #define MAXUSERID 10 50 51 /* Structures and unions */ 52 53 /* Function declarations */ 54 55 static int check_for_user(FILE *fp, const char *name); 56 57 /* Local functions */ 58 59 static int 60 check_for_user(FILE *fp, const char *name) 61 { 62 char *buffer; 63 size_t len; 64 int found = 0; 65 66 len = strlen(name); 67 if ((buffer = malloc(len+2)) == NULL) 68 errx(EXIT_FAILURE, "virtual memory exhausted"); 69 70 while(fgets(buffer, len+2, fp) != NULL) 71 { 72 if ((strncmp(name, buffer, len) == 0) && 73 (buffer[len] == '\n')) 74 { 75 found = 1; 76 break; 77 } 78 } 79 fclose(fp); 80 free(buffer); 81 return found; 82 } 83 84 /* Global functions */ 85 int 86 check_permission(void) 87 { 88 FILE *fp; 89 uid_t uid = geteuid(); 90 struct passwd *pentry; 91 92 if (uid==0) 93 return 1; 94 95 if ((pentry = getpwuid(uid)) == NULL) 96 err(EXIT_FAILURE, "cannot access user database"); 97 98 PRIV_START 99 100 fp = fopen(PERM_PATH "at.allow","r"); 101 102 PRIV_END 103 104 if (fp != NULL) 105 { 106 return check_for_user(fp, pentry->pw_name); 107 } 108 else if (errno == ENOENT) 109 { 110 111 PRIV_START 112 113 fp = fopen(PERM_PATH "at.deny", "r"); 114 115 PRIV_END 116 117 if (fp != NULL) 118 { 119 return !check_for_user(fp, pentry->pw_name); 120 } 121 else if (errno != ENOENT) 122 warn("at.deny"); 123 } 124 else 125 warn("at.allow"); 126 return 0; 127 } 128