155682Smarkm/* 2178825Sdfr * Copyright (c) 1997 - 2005 Kungliga Tekniska H�gskolan 355682Smarkm * (Royal Institute of Technology, Stockholm, Sweden). 455682Smarkm * All rights reserved. 555682Smarkm * 655682Smarkm * Redistribution and use in source and binary forms, with or without 755682Smarkm * modification, are permitted provided that the following conditions 855682Smarkm * are met: 955682Smarkm * 1055682Smarkm * 1. Redistributions of source code must retain the above copyright 1155682Smarkm * notice, this list of conditions and the following disclaimer. 1255682Smarkm * 1355682Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1455682Smarkm * notice, this list of conditions and the following disclaimer in the 1555682Smarkm * documentation and/or other materials provided with the distribution. 1655682Smarkm * 1755682Smarkm * 3. Neither the name of the Institute nor the names of its contributors 1855682Smarkm * may be used to endorse or promote products derived from this software 1955682Smarkm * without specific prior written permission. 2055682Smarkm * 2155682Smarkm * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 2255682Smarkm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2355682Smarkm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2455682Smarkm * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 2555682Smarkm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2655682Smarkm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2755682Smarkm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2855682Smarkm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2955682Smarkm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3055682Smarkm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3155682Smarkm * SUCH DAMAGE. 3255682Smarkm */ 3355682Smarkm 3455682Smarkm#include "krb5_locl.h" 35178825Sdfr#include <dirent.h> 3655682Smarkm 37178825SdfrRCSID("$Id: kuserok.c 16048 2005-09-09 10:33:33Z lha $"); 3855682Smarkm 39178825Sdfr/* see if principal is mentioned in the filename access file, return 40178825Sdfr TRUE (in result) if so, FALSE otherwise */ 41178825Sdfr 42178825Sdfrstatic krb5_error_code 43178825Sdfrcheck_one_file(krb5_context context, 44178825Sdfr const char *filename, 45178825Sdfr struct passwd *pwd, 46178825Sdfr krb5_principal principal, 47178825Sdfr krb5_boolean *result) 48178825Sdfr{ 49178825Sdfr FILE *f; 50178825Sdfr char buf[BUFSIZ]; 51178825Sdfr krb5_error_code ret; 52178825Sdfr struct stat st; 53178825Sdfr 54178825Sdfr *result = FALSE; 55178825Sdfr 56178825Sdfr f = fopen (filename, "r"); 57178825Sdfr if (f == NULL) 58178825Sdfr return errno; 59178825Sdfr 60178825Sdfr /* check type and mode of file */ 61178825Sdfr if (fstat(fileno(f), &st) != 0) { 62178825Sdfr fclose (f); 63178825Sdfr return errno; 64178825Sdfr } 65178825Sdfr if (S_ISDIR(st.st_mode)) { 66178825Sdfr fclose (f); 67178825Sdfr return EISDIR; 68178825Sdfr } 69178825Sdfr if (st.st_uid != pwd->pw_uid && st.st_uid != 0) { 70178825Sdfr fclose (f); 71178825Sdfr return EACCES; 72178825Sdfr } 73178825Sdfr if ((st.st_mode & (S_IWGRP | S_IWOTH)) != 0) { 74178825Sdfr fclose (f); 75178825Sdfr return EACCES; 76178825Sdfr } 77178825Sdfr 78178825Sdfr while (fgets (buf, sizeof(buf), f) != NULL) { 79178825Sdfr krb5_principal tmp; 80178825Sdfr char *newline = buf + strcspn(buf, "\n"); 81178825Sdfr 82178825Sdfr if(*newline != '\n') { 83178825Sdfr int c; 84178825Sdfr c = fgetc(f); 85178825Sdfr if(c != EOF) { 86178825Sdfr while(c != EOF && c != '\n') 87178825Sdfr c = fgetc(f); 88178825Sdfr /* line was too long, so ignore it */ 89178825Sdfr continue; 90178825Sdfr } 91178825Sdfr } 92178825Sdfr *newline = '\0'; 93178825Sdfr ret = krb5_parse_name (context, buf, &tmp); 94178825Sdfr if (ret) 95178825Sdfr continue; 96178825Sdfr *result = krb5_principal_compare (context, principal, tmp); 97178825Sdfr krb5_free_principal (context, tmp); 98178825Sdfr if (*result) { 99178825Sdfr fclose (f); 100178825Sdfr return 0; 101178825Sdfr } 102178825Sdfr } 103178825Sdfr fclose (f); 104178825Sdfr return 0; 105178825Sdfr} 106178825Sdfr 107178825Sdfrstatic krb5_error_code 108178825Sdfrcheck_directory(krb5_context context, 109178825Sdfr const char *dirname, 110178825Sdfr struct passwd *pwd, 111178825Sdfr krb5_principal principal, 112178825Sdfr krb5_boolean *result) 113178825Sdfr{ 114178825Sdfr DIR *d; 115178825Sdfr struct dirent *dent; 116178825Sdfr char filename[MAXPATHLEN]; 117178825Sdfr krb5_error_code ret = 0; 118178825Sdfr struct stat st; 119178825Sdfr 120178825Sdfr *result = FALSE; 121178825Sdfr 122178825Sdfr if(lstat(dirname, &st) < 0) 123178825Sdfr return errno; 124178825Sdfr 125178825Sdfr if (!S_ISDIR(st.st_mode)) 126178825Sdfr return ENOTDIR; 127178825Sdfr 128178825Sdfr if (st.st_uid != pwd->pw_uid && st.st_uid != 0) 129178825Sdfr return EACCES; 130178825Sdfr if ((st.st_mode & (S_IWGRP | S_IWOTH)) != 0) 131178825Sdfr return EACCES; 132178825Sdfr 133178825Sdfr if((d = opendir(dirname)) == NULL) 134178825Sdfr return errno; 135178825Sdfr 136178825Sdfr#ifdef HAVE_DIRFD 137178825Sdfr { 138178825Sdfr int fd; 139178825Sdfr struct stat st2; 140178825Sdfr 141178825Sdfr fd = dirfd(d); 142178825Sdfr if(fstat(fd, &st2) < 0) { 143178825Sdfr closedir(d); 144178825Sdfr return errno; 145178825Sdfr } 146178825Sdfr if(st.st_dev != st2.st_dev || st.st_ino != st2.st_ino) { 147178825Sdfr closedir(d); 148178825Sdfr return EACCES; 149178825Sdfr } 150178825Sdfr } 151178825Sdfr#endif 152178825Sdfr 153178825Sdfr while((dent = readdir(d)) != NULL) { 154178825Sdfr if(strcmp(dent->d_name, ".") == 0 || 155178825Sdfr strcmp(dent->d_name, "..") == 0 || 156178825Sdfr dent->d_name[0] == '#' || /* emacs autosave */ 157178825Sdfr dent->d_name[strlen(dent->d_name) - 1] == '~') /* emacs backup */ 158178825Sdfr continue; 159178825Sdfr snprintf(filename, sizeof(filename), "%s/%s", dirname, dent->d_name); 160178825Sdfr ret = check_one_file(context, filename, pwd, principal, result); 161178825Sdfr if(ret == 0 && *result == TRUE) 162178825Sdfr break; 163178825Sdfr ret = 0; /* don't propagate errors upstream */ 164178825Sdfr } 165178825Sdfr closedir(d); 166178825Sdfr return ret; 167178825Sdfr} 168178825Sdfr 169178825Sdfrstatic krb5_boolean 170178825Sdfrmatch_local_principals(krb5_context context, 171178825Sdfr krb5_principal principal, 172178825Sdfr const char *luser) 173178825Sdfr{ 174178825Sdfr krb5_error_code ret; 175178825Sdfr krb5_realm *realms, *r; 176178825Sdfr krb5_boolean result = FALSE; 177178825Sdfr 178178825Sdfr /* multi-component principals can never match */ 179178825Sdfr if(krb5_principal_get_comp_string(context, principal, 1) != NULL) 180178825Sdfr return FALSE; 181178825Sdfr 182178825Sdfr ret = krb5_get_default_realms (context, &realms); 183178825Sdfr if (ret) 184178825Sdfr return FALSE; 185178825Sdfr 186178825Sdfr for (r = realms; *r != NULL; ++r) { 187178825Sdfr if(strcmp(krb5_principal_get_realm(context, principal), 188178825Sdfr *r) != 0) 189178825Sdfr continue; 190178825Sdfr if(strcmp(krb5_principal_get_comp_string(context, principal, 0), 191178825Sdfr luser) == 0) { 192178825Sdfr result = TRUE; 193178825Sdfr break; 194178825Sdfr } 195178825Sdfr } 196178825Sdfr krb5_free_host_realm (context, realms); 197178825Sdfr return result; 198178825Sdfr} 199178825Sdfr 200178825Sdfr/** 20155682Smarkm * Return TRUE iff `principal' is allowed to login as `luser'. 20255682Smarkm */ 20355682Smarkm 204178825Sdfrkrb5_boolean KRB5_LIB_FUNCTION 20555682Smarkmkrb5_kuserok (krb5_context context, 20655682Smarkm krb5_principal principal, 20755682Smarkm const char *luser) 20855682Smarkm{ 209178825Sdfr char *buf; 210178825Sdfr size_t buflen; 21155682Smarkm struct passwd *pwd; 21255682Smarkm krb5_error_code ret; 213178825Sdfr krb5_boolean result = FALSE; 21455682Smarkm 215178825Sdfr krb5_boolean found_file = FALSE; 216178825Sdfr 217178825Sdfr#ifdef POSIX_GETPWNAM_R 218178825Sdfr char pwbuf[2048]; 219178825Sdfr struct passwd pw; 220178825Sdfr 221178825Sdfr if(getpwnam_r(luser, &pw, pwbuf, sizeof(pwbuf), &pwd) != 0) 222178825Sdfr return FALSE; 223178825Sdfr#else 224178825Sdfr pwd = getpwnam (luser); 225178825Sdfr#endif 226120945Snectar if (pwd == NULL) 227120945Snectar return FALSE; 228120945Snectar 229178825Sdfr#define KLOGIN "/.k5login" 230178825Sdfr buflen = strlen(pwd->pw_dir) + sizeof(KLOGIN) + 2; /* 2 for .d */ 231178825Sdfr buf = malloc(buflen); 232178825Sdfr if(buf == NULL) 23355682Smarkm return FALSE; 234178825Sdfr /* check user's ~/.k5login */ 235178825Sdfr strlcpy(buf, pwd->pw_dir, buflen); 236178825Sdfr strlcat(buf, KLOGIN, buflen); 237178825Sdfr ret = check_one_file(context, buf, pwd, principal, &result); 23855682Smarkm 239178825Sdfr if(ret == 0 && result == TRUE) { 240178825Sdfr free(buf); 241178825Sdfr return TRUE; 242178825Sdfr } 24355682Smarkm 244178825Sdfr if(ret != ENOENT) 245178825Sdfr found_file = TRUE; 24655682Smarkm 247178825Sdfr strlcat(buf, ".d", buflen); 248178825Sdfr ret = check_directory(context, buf, pwd, principal, &result); 249178825Sdfr free(buf); 250178825Sdfr if(ret == 0 && result == TRUE) 251178825Sdfr return TRUE; 25255682Smarkm 253178825Sdfr if(ret != ENOENT && ret != ENOTDIR) 254178825Sdfr found_file = TRUE; 25555682Smarkm 256178825Sdfr /* finally if no files exist, allow all principals matching 257178825Sdfr <localuser>@<LOCALREALM> */ 258178825Sdfr if(found_file == FALSE) 259178825Sdfr return match_local_principals(context, principal, luser); 260178825Sdfr 26155682Smarkm return FALSE; 26255682Smarkm} 263