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/* $OpenBSD: kuserok.c,v 1.6 1997/12/12 05:30:26 art Exp $ */
/* $KTH: kuserok.c,v 1.21 1997/04/01 08:18:35 joda Exp $ */
/*
* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Kungliga Tekniska
* Högskolan and its contributors.
*
* 4. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb_locl.h"
#define OK 0
#define NOTOK 1
#define MAX_USERNAME 10
/*
* Given a Kerberos principal and a local username, determine whether
* user is authorized to login according to the authorization file
* ("~luser/.klogin" by default). Returns OK if authorized, NOTOK if
* not authorized.
*
* IMPORTANT CHANGE: To eliminate the need of making a distinction
* between the 3 cases:
*
* 1. We can't verify that a .klogin file doesn't exist (no home dir).
* 2. It's there but we aren't allowed to read it.
* 3. We can read it and ~luser@LOCALREALM is (not) included.
*
* We instead make the assumption that luser@LOCALREALM is *always*
* included. Thus it is impossible to have an empty .klogin file and
* also to exclude luser@LOCALREALM from it. Root is treated differently
* since it's home should always be available.
*
* OLD STRATEGY:
* If there is no account for "luser" on the local machine, returns
* NOTOK. If there is no authorization file, and the given Kerberos
* name "kdata" translates to the same name as "luser" (using
* krb_kntoln()), returns OK. Otherwise, if the authorization file
* can't be accessed, returns NOTOK. Otherwise, the file is read for
* a matching principal name, instance, and realm. If one is found,
* returns OK, if none is found, returns NOTOK.
*
* The file entries are in the format:
*
* name.instance@realm
*
* one entry per line.
*
*/
int
krb_kuserok(char *name, char *instance, char *realm, char *luser)
{
struct passwd *pwd;
char lrealm[REALM_SZ];
FILE *f;
char line[1024];
char file[MAXPATHLEN];
struct stat st;
if (luser == NULL)
return NOTOK;
pwd = getpwnam(luser);
if(pwd == NULL)
return NOTOK;
if(krb_get_lrealm(lrealm, 1))
return NOTOK;
if(pwd->pw_uid != 0 &&
strcmp(name, luser) == 0 &&
strcmp(instance, "") == 0 &&
strcmp(realm, lrealm) == 0)
return OK;
snprintf(file, sizeof(file), "%s/.klogin", pwd->pw_dir);
f = fopen(file, "r");
if(f == NULL)
return NOTOK;
/* this is not a working test in filesystems like AFS and DFS */
if(fstat(fileno(f), &st) < 0){
fclose(f);
return NOTOK;
}
if(st.st_uid != pwd->pw_uid){
fclose(f);
return NOTOK;
}
while(fgets(line, sizeof(line), f)){
char fname[ANAME_SZ], finst[INST_SZ], frealm[REALM_SZ];
if(line[strlen(line) - 1] != '\n')
/* read till end of line */
while(1){
int c = fgetc(f);
if(c == '\n' || c == EOF)
break;
}
else
line[strlen(line) - 1] = 0;
if(kname_parse(fname, finst, frealm, line))
continue;
if(strcmp(name, fname))
continue;
if(strcmp(instance, finst))
continue;
if(frealm[0] == 0)
{
strncpy(frealm, lrealm, REALM_SZ);
frealm[REALM_SZ-1] = '\0';
}
if(strcmp(realm, frealm))
continue;
fclose(f);
return OK;
}
fclose(f);
return NOTOK;
}
/* compatibility interface */
int
kuserok(AUTH_DAT *auth, char *luser)
{
return krb_kuserok(auth->pname, auth->pinst, auth->prealm, luser);
}
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