several new kerberos related libraries and applications to FreeBSD: o kgetcred(1) allows one to manually get a ticket for a particular service. o kf(1) securily forwards ticket to another host through an authenticated and encrypted stream. o kcc(1) is an umbrella program around klist(1), kswitch(1), kgetcred(1) and other user kerberos operations. klist and kswitch are just symlinks to kcc(1) now. o kswitch(1) allows you to easily switch between kerberos credentials if you're running KCM. o hxtool(1) is a certificate management tool to use with PKINIT. o string2key(1) maps a password into key. o kdigest(8) is a userland tool to access the KDC's digest interface. o kimpersonate(8) creates a "fake" ticket for a service. We also now install manpages for some lirbaries that were not installed before, libheimntlm and libhx509. - The new HEIMDAL version no longer supports Kerberos 4. All users are recommended to switch to Kerberos 5. - Weak ciphers are now disabled by default. To enable DES support (used by telnet(8)), use "allow_weak_crypto" option in krb5.conf. - libtelnet, pam_ksu and pam_krb5 are now compiled with error on warnings disabled due to the function they use (krb5_get_err_text(3)) being deprecated. I plan to work on this next. - Heimdal's KDC now require sqlite to operate. We use the bundled version and install it as libheimsqlite. If some other FreeBSD components will require it in the future we can rename it to libbsdsqlite and use for these components as well. - This is not a latest Heimdal version, the new one was released while I was working on the update. I will update it to 1.5.2 soon, as it fixes some important bugs and security issues.
304 lines
8.1 KiB
C
304 lines
8.1 KiB
C
/*
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* Copyright (c) 1997 - 2005 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "krb5_locl.h"
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#include <dirent.h>
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#ifndef _WIN32
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/* see if principal is mentioned in the filename access file, return
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TRUE (in result) if so, FALSE otherwise */
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static krb5_error_code
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check_one_file(krb5_context context,
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const char *filename,
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struct passwd *pwd,
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krb5_principal principal,
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krb5_boolean *result)
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{
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FILE *f;
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char buf[BUFSIZ];
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krb5_error_code ret;
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struct stat st;
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*result = FALSE;
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f = fopen (filename, "r");
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if (f == NULL)
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return errno;
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rk_cloexec_file(f);
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/* check type and mode of file */
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if (fstat(fileno(f), &st) != 0) {
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fclose (f);
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return errno;
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}
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if (S_ISDIR(st.st_mode)) {
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fclose (f);
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return EISDIR;
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}
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if (st.st_uid != pwd->pw_uid && st.st_uid != 0) {
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fclose (f);
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return EACCES;
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}
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if ((st.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
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fclose (f);
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return EACCES;
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}
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while (fgets (buf, sizeof(buf), f) != NULL) {
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krb5_principal tmp;
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char *newline = buf + strcspn(buf, "\n");
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if(*newline != '\n') {
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int c;
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c = fgetc(f);
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if(c != EOF) {
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while(c != EOF && c != '\n')
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c = fgetc(f);
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/* line was too long, so ignore it */
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continue;
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}
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}
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*newline = '\0';
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ret = krb5_parse_name (context, buf, &tmp);
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if (ret)
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continue;
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*result = krb5_principal_compare (context, principal, tmp);
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krb5_free_principal (context, tmp);
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if (*result) {
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fclose (f);
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return 0;
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}
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}
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fclose (f);
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return 0;
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}
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static krb5_error_code
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check_directory(krb5_context context,
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const char *dirname,
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struct passwd *pwd,
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krb5_principal principal,
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krb5_boolean *result)
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{
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DIR *d;
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struct dirent *dent;
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char filename[MAXPATHLEN];
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krb5_error_code ret = 0;
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struct stat st;
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*result = FALSE;
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if(lstat(dirname, &st) < 0)
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return errno;
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if (!S_ISDIR(st.st_mode))
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return ENOTDIR;
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if (st.st_uid != pwd->pw_uid && st.st_uid != 0)
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return EACCES;
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if ((st.st_mode & (S_IWGRP | S_IWOTH)) != 0)
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return EACCES;
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if((d = opendir(dirname)) == NULL)
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return errno;
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{
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int fd;
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struct stat st2;
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fd = dirfd(d);
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if(fstat(fd, &st2) < 0) {
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closedir(d);
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return errno;
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}
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if(st.st_dev != st2.st_dev || st.st_ino != st2.st_ino) {
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closedir(d);
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return EACCES;
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}
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}
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while((dent = readdir(d)) != NULL) {
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if(strcmp(dent->d_name, ".") == 0 ||
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strcmp(dent->d_name, "..") == 0 ||
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dent->d_name[0] == '#' || /* emacs autosave */
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dent->d_name[strlen(dent->d_name) - 1] == '~') /* emacs backup */
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continue;
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snprintf(filename, sizeof(filename), "%s/%s", dirname, dent->d_name);
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ret = check_one_file(context, filename, pwd, principal, result);
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if(ret == 0 && *result == TRUE)
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break;
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ret = 0; /* don't propagate errors upstream */
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}
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closedir(d);
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return ret;
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}
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#endif /* !_WIN32 */
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static krb5_boolean
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match_local_principals(krb5_context context,
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krb5_principal principal,
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const char *luser)
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{
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krb5_error_code ret;
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krb5_realm *realms, *r;
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krb5_boolean result = FALSE;
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/* multi-component principals can never match */
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if(krb5_principal_get_comp_string(context, principal, 1) != NULL)
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return FALSE;
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ret = krb5_get_default_realms (context, &realms);
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if (ret)
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return FALSE;
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for (r = realms; *r != NULL; ++r) {
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if(strcmp(krb5_principal_get_realm(context, principal),
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*r) != 0)
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continue;
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if(strcmp(krb5_principal_get_comp_string(context, principal, 0),
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luser) == 0) {
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result = TRUE;
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break;
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}
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}
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krb5_free_host_realm (context, realms);
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return result;
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}
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/**
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* This function takes the name of a local user and checks if
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* principal is allowed to log in as that user.
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*
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* The user may have a ~/.k5login file listing principals that are
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* allowed to login as that user. If that file does not exist, all
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* principals with a first component identical to the username, and a
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* realm considered local, are allowed access.
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*
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* The .k5login file must contain one principal per line, be owned by
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* user and not be writable by group or other (but must be readable by
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* anyone).
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*
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* Note that if the file exists, no implicit access rights are given
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* to user@@LOCALREALM.
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*
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* Optionally, a set of files may be put in ~/.k5login.d (a
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* directory), in which case they will all be checked in the same
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* manner as .k5login. The files may be called anything, but files
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* starting with a hash (#) , or ending with a tilde (~) are
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* ignored. Subdirectories are not traversed. Note that this directory
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* may not be checked by other Kerberos implementations.
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*
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* If no configuration file exists, match user against local domains,
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* ie luser@@LOCAL-REALMS-IN-CONFIGURATION-FILES.
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*
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* @param context Kerberos 5 context.
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* @param principal principal to check if allowed to login
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* @param luser local user id
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*
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* @return returns TRUE if access should be granted, FALSE otherwise.
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*
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* @ingroup krb5_support
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*/
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KRB5_LIB_FUNCTION krb5_boolean KRB5_LIB_CALL
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krb5_kuserok (krb5_context context,
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krb5_principal principal,
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const char *luser)
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{
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#ifndef _WIN32
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char *buf;
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size_t buflen;
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struct passwd *pwd = NULL;
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char *profile_dir = NULL;
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krb5_error_code ret;
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krb5_boolean result = FALSE;
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krb5_boolean found_file = FALSE;
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#ifdef POSIX_GETPWNAM_R
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char pwbuf[2048];
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struct passwd pw;
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if(getpwnam_r(luser, &pw, pwbuf, sizeof(pwbuf), &pwd) != 0)
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return FALSE;
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#else
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pwd = getpwnam (luser);
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#endif
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if (pwd == NULL)
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return FALSE;
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profile_dir = pwd->pw_dir;
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#define KLOGIN "/.k5login"
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buflen = strlen(profile_dir) + sizeof(KLOGIN) + 2; /* 2 for .d */
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buf = malloc(buflen);
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if(buf == NULL)
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return FALSE;
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/* check user's ~/.k5login */
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strlcpy(buf, profile_dir, buflen);
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strlcat(buf, KLOGIN, buflen);
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ret = check_one_file(context, buf, pwd, principal, &result);
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if(ret == 0 && result == TRUE) {
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free(buf);
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return TRUE;
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}
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if(ret != ENOENT)
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found_file = TRUE;
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strlcat(buf, ".d", buflen);
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ret = check_directory(context, buf, pwd, principal, &result);
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free(buf);
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if(ret == 0 && result == TRUE)
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return TRUE;
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if(ret != ENOENT && ret != ENOTDIR)
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found_file = TRUE;
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/* finally if no files exist, allow all principals matching
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<localuser>@<LOCALREALM> */
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if(found_file == FALSE)
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return match_local_principals(context, principal, luser);
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return FALSE;
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#else
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/* The .k5login file may be on a remote profile and we don't have
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access to the profile until we have a token handle for the
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user's credentials. */
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return match_local_principals(context, principal, luser);
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#endif
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}
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