BSD 4_3_Reno development

[unix-history] / usr / src / kerberosIV / krb / kuserok.c

/*
* $Source: /usr/src/kerberosIV/krb/RCS/kuserok.c,v $
* $Author: kfall $
*
* Copyright 1987, 1988 by the Massachusetts Institute of Technology.
*
* For copying and distribution information, please see the file
* <mit-copyright.h>.
*
* kuserok: check if a kerberos principal has
* access to a local account
*/

#ifndef lint
static char rcsid_kuserok_c[] =
"$Header: /usr/src/kerberosIV/krb/RCS/kuserok.c,v 4.7 90/06/23 03:11:11 kfall Exp $";
#endif  lint

#include <mit-copyright.h>

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <des.h>
#include <krb.h>
#include <stdio.h>
#include <pwd.h>
#include <strings.h>

#define OK 0
#define NOTOK 1
#define MAX_USERNAME 10

/*
* Given a Kerberos principal "kdata", and a local username "luser",
* determine whether user is authorized to login according to the
* authorization file ("~luser/.klogin" by default).  Returns OK
* if authorized, NOTOK if not authorized.
*
* 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.
*
* The ATHENA_COMPAT code supports old-style Athena ~luser/.klogin
* file entries.  See the file "kparse.c".
*/

int
kuserok(kdata, luser)
   AUTH_DAT *kdata;
   char   *luser;
{
   struct stat sbuf;
   struct passwd *pwd;
   char pbuf[MAXPATHLEN];
   int isok = NOTOK, rc;
   FILE *fp;
   char kuser[MAX_USERNAME];
   char principal[ANAME_SZ], inst[INST_SZ], realm[REALM_SZ];
   char linebuf[BUFSIZ];
   char *newline;
   int gobble;

   /* no account => no access */
   if ((pwd = getpwnam(luser)) == NULL) {
       return(NOTOK);
   }
   (void) strcpy(pbuf, pwd->pw_dir);
   (void) strcat(pbuf, "/.klogin");

   if (access(pbuf, F_OK)) {    /* not accessible */
       /*
        * if he's trying to log in as himself, and there is no .klogin file,
        * let him.  To find out, call
        * krb_kntoln to convert the triple in kdata to a name which we can
        * string compare. 
        */
       if (!krb_kntoln(kdata, kuser) && (strcmp(kuser, luser) == 0)) {
           return(OK);
       }
   }
   /* open ~/.klogin */
   if ((fp = fopen(pbuf, "r")) == NULL) {
       return(NOTOK);
   }
   /*
    * security:  if the user does not own his own .klogin file,
    * do not grant access
    */
   if (fstat(fileno(fp), &sbuf)) {
       fclose(fp);
       return(NOTOK);
   }
   if (sbuf.st_uid != pwd->pw_uid) {
       fclose(fp);
       return(NOTOK);
   }

   /* check each line */
   while ((isok != OK) && (fgets(linebuf, BUFSIZ, fp) != NULL)) {
       /* null-terminate the input string */
       linebuf[BUFSIZ-1] = '\0';
       newline = NULL;
       /* nuke the newline if it exists */
       if (newline = index(linebuf, '\n'))
           *newline = '\0';
       rc = kname_parse(principal, inst, realm, linebuf);
       if (rc == KSUCCESS) {
           isok = (strncmp(kdata->pname, principal, ANAME_SZ) ||
                   strncmp(kdata->pinst, inst, INST_SZ) ||
                   strncasecmp(kdata->prealm, realm, REALM_SZ));
       }
       /* clean up the rest of the line if necessary */
       if (!newline)
           while (((gobble = getc(fp)) != EOF) && gobble != '\n');
   }
   fclose(fp);
   return(isok);
}