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 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 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 "at.h" 44 #include "perm.h" 45 #include "privs.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 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 if ((buffer = malloc(len+2)) == NULL) 67 errx(EXIT_FAILURE, "virtual memory exhausted"); 68 69 while(fgets(buffer, len+2, fp) != NULL) 70 { 71 if ((strncmp(name, buffer, len) == 0) && 72 (buffer[len] == '\n')) 73 { 74 found = 1; 75 break; 76 } 77 } 78 fclose(fp); 79 free(buffer); 80 return found; 81 } 82 /* Global functions */ 83 int check_permission(void) 84 { 85 FILE *fp; 86 uid_t uid = geteuid(); 87 struct passwd *pentry; 88 89 if (uid==0) 90 return 1; 91 92 if ((pentry = getpwuid(uid)) == NULL) 93 err(EXIT_FAILURE, "cannot access user database"); 94 95 PRIV_START 96 97 fp=fopen(PERM_PATH "at.allow","r"); 98 99 PRIV_END 100 101 if (fp != NULL) 102 { 103 return check_for_user(fp, pentry->pw_name); 104 } 105 else if (errno == ENOENT) 106 { 107 108 PRIV_START 109 110 fp=fopen(PERM_PATH "at.deny", "r"); 111 112 PRIV_END 113 114 if (fp != NULL) 115 { 116 return !check_for_user(fp, pentry->pw_name); 117 } 118 else if (errno != ENOENT) 119 warn("at.deny"); 120 } 121 else 122 warn("at.allow"); 123 return 0; 124 } 125