1 /*- 2 * perm.c - check user permission for at(1) 3 * 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (C) 1994 Thomas Koenig 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. The name of the author(s) may not be used to endorse or promote 14 * products derived from this software without specific prior written 15 * permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 /* System Headers */ 33 34 #include <sys/types.h> 35 #include <err.h> 36 #include <errno.h> 37 #include <pwd.h> 38 #include <stddef.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 /* Local headers */ 45 46 #include "at.h" 47 #include "perm.h" 48 #include "privs.h" 49 50 /* Macros */ 51 52 #define MAXUSERID 10 53 54 /* Structures and unions */ 55 56 /* Function declarations */ 57 58 static int check_for_user(FILE *fp,const char *name); 59 60 /* Local functions */ 61 62 static int check_for_user(FILE *fp,const char *name) 63 { 64 char *buffer; 65 size_t len; 66 int found = 0; 67 68 len = strlen(name); 69 if ((buffer = malloc(len+2)) == NULL) 70 errx(EXIT_FAILURE, "virtual memory exhausted"); 71 72 while(fgets(buffer, len+2, fp) != NULL) 73 { 74 if ((strncmp(name, buffer, len) == 0) && 75 (buffer[len] == '\n')) 76 { 77 found = 1; 78 break; 79 } 80 } 81 fclose(fp); 82 free(buffer); 83 return found; 84 } 85 /* Global functions */ 86 int 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