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/*
* lib/krb5/os/kuserok.c
*
* Copyright 1990,1993 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* krb5_kuserok()
*/
#include "k5-int.h"
#if !defined(_MSDOS) && !defined(_WIN32) && !defined(macintosh) /* Not yet for Windows */
#include <stdio.h>
#include <pwd.h>
#if defined(_AIX) && defined(_IBMR2)
#include <sys/access.h>
/* xlc has a bug with "const" */
#define getpwnam(user) getpwnam((char *)user)
#endif
#define MAX_USERNAME 10
/*
* Given a Kerberos principal "principal", and a local username "luser",
* determine whether user is authorized to login according to the
* authorization file ("~luser/.k5login" by default). Returns TRUE
* if authorized, FALSE if not authorized.
*
* If there is no account for "luser" on the local machine, returns
* FALSE. If there is no authorization file, and the given Kerberos
* name "server" translates to the same name as "luser" (using
* krb5_aname_to_lname()), returns TRUE. Otherwise, if the authorization file
* can't be accessed, returns FALSE. Otherwise, the file is read for
* a matching principal name, instance, and realm. If one is found,
* returns TRUE, if none is found, returns FALSE.
*
* The file entries are in the format produced by krb5_unparse_name(),
* one entry per line.
*
*/
krb5_boolean KRB5_CALLCONV
krb5_kuserok(context, principal, luser)
krb5_context context;
krb5_principal principal;
const char *luser;
{
struct stat sbuf;
struct passwd *pwd;
char pbuf[MAXPATHLEN];
krb5_boolean isok = FALSE;
FILE *fp;
char kuser[MAX_USERNAME];
char *princname;
char linebuf[BUFSIZ];
char *newline;
int gobble;
/* no account => no access */
if ((pwd = getpwnam(luser)) == NULL) {
return(FALSE);
}
(void) strcpy(pbuf, pwd->pw_dir);
(void) strcat(pbuf, "/.k5login");
if (access(pbuf, F_OK)) { /* not accessible */
/*
* if he's trying to log in as himself, and there is no .k5login file,
* let him. To find out, call
* krb5_aname_to_localname to convert the principal to a name
* which we can string compare.
*/
if (!(krb5_aname_to_localname(context, principal,
sizeof(kuser), kuser))
&& (strcmp(kuser, luser) == 0)) {
return(TRUE);
}
}
if (krb5_unparse_name(context, principal, &princname))
return(FALSE); /* no hope of matching */
/* open ~/.k5login */
if ((fp = fopen(pbuf, "r")) == NULL) {
free(princname);
return(FALSE);
}
/*
* For security reasons, the .k5login file must be owned either by
* the user himself, or by root. Otherwise, don't grant access.
*/
if (fstat(fileno(fp), &sbuf)) {
fclose(fp);
free(princname);
return(FALSE);
}
if ((sbuf.st_uid != pwd->pw_uid) && sbuf.st_uid) {
fclose(fp);
free(princname);
return(FALSE);
}
/* check each line */
while (!isok && (fgets(linebuf, BUFSIZ, fp) != NULL)) {
/* null-terminate the input string */
linebuf[BUFSIZ-1] = '\0';
newline = NULL;
/* nuke the newline if it exists */
if ((newline = strchr(linebuf, '\n')))
*newline = '\0';
if (!strcmp(linebuf, princname)) {
isok = TRUE;
continue;
}
/* clean up the rest of the line if necessary */
if (!newline)
while (((gobble = getc(fp)) != EOF) && gobble != '\n');
}
free(princname);
fclose(fp);
return(isok);
}
#else /* _MSDOS */
/*
* If the given Kerberos name "server" translates to the same name as "luser"
* (using * krb5_aname_to_lname()), returns TRUE.
*/
krb5_boolean KRB5_CALLCONV
krb5_kuserok(context, principal, luser)
krb5_context context;
krb5_principal principal;
const char *luser;
{
char kuser[50];
if (krb5_aname_to_localname(context, principal, sizeof(kuser), kuser))
return FALSE;
if (strcmp(kuser, luser) == 0)
return TRUE;
return FALSE;
}
#endif /* _MSDOS */
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