/* * Copyright 1987, 1988 by the Massachusetts Institute of Technology. * For copying and distribution information, please see the file * . * * kuserok: check if a kerberos principal has * access to a local account * * from: kuserok.c,v 4.5 89/01/23 09:25:21 jtkohl Exp $ * $Id: kuserok.c,v 1.1.1.1 1994/09/30 14:50:02 csgr Exp $ */ #ifndef lint static char rcsid[] = "$Id: kuserok.c,v 1.1.1.1 1994/09/30 14:50:02 csgr Exp $"; #endif lint #include #include #include #include #include #include #include #include #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". */ #ifdef ATHENA_COMPAT #include /* * The parmtable defines the keywords we will recognize with their * default values, and keeps a pointer to the found value. The found * value should be filled in with strsave(), since FreeParameterSet() * will release memory for all non-NULL found strings. * *** NOTE WELL! *** * * The table below is very nice, but we cannot hard-code a default for the * realm: we have to get the realm via krb_get_lrealm(). Even though the * default shows as "from krb_get_lrealm, below", it gets changed in * kuserok to whatever krb_get_lrealm() tells us. That code assumes that * the realm will be the entry number in the table below, so if you * change the order of the entries below, you have to change the * #definition of REALM_SCRIPT to reflect it. */ #define REALM_SUBSCRIPT 1 parmtable kparm[] = { /* keyword default found value */ {"user", "", (char *) NULL}, {"realm", "see krb_get_lrealm, below", (char *) NULL}, {"instance", "", (char *) NULL}, }; #define KPARMS kparm,PARMCOUNT(kparm) #endif ATHENA_COMPAT 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; #ifdef ATHENA_COMPAT char local_realm[REALM_SZ]; #endif ATHENA_COMPAT /* 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); } #ifdef ATHENA_COMPAT /* Accept old-style .klogin files */ /* * change the default realm from the hard-coded value to the * accepted realm that Kerberos specifies. */ rc = krb_get_lrealm(local_realm, 1); if (rc == KSUCCESS) kparm[REALM_SUBSCRIPT].defvalue = local_realm; else return (rc); /* check each line */ while ((isok != OK) && (rc = fGetParameterSet(fp, KPARMS)) != PS_EOF) { switch (rc) { case PS_BAD_KEYWORD: case PS_SYNTAX: while (((gobble = fGetChar(fp)) != EOF) && (gobble != '\n')); break; case PS_OKAY: isok = (ParmCompare(KPARMS, "user", kdata->pname) || ParmCompare(KPARMS, "instance", kdata->pinst) || ParmCompare(KPARMS, "realm", kdata->prealm)); break; default: break; } FreeParameterSet(kparm, PARMCOUNT(kparm)); } /* reset the stream for parsing new-style names, if necessary */ rewind(fp); #endif ATHENA_COMPAT /* 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) || strncmp(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); }