118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
/*
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Copyright (C) 1989 by the Massachusetts Institute of Technology
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Export of this software from the United States of America is assumed
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to require a specific license from the United States Government.
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It is the responsibility of any person or organization contemplating
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export to obtain such a license before exporting.
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WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
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distribute this software and its documentation for any purpose and
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without fee is hereby granted, provided that the above copyright
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notice appear in all copies and that both that copyright notice and
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this permission notice appear in supporting documentation, and that
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the name of M.I.T. not be used in advertising or publicity pertaining
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to distribution of the software without specific, written prior
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permission. M.I.T. makes no representations about the suitability of
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this software for any purpose. It is provided "as is" without express
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or implied warranty.
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*/
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#include "krb_locl.h"
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RCSID("$Id: read_service_key.c,v 1.11 1999/03/10 18:34:34 joda Exp $");
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/*
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* The private keys for servers on a given host are stored in a
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* "srvtab" file (typically "/etc/srvtab"). This routine extracts
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* a given server's key from the file.
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*
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* read_service_key() takes the server's name ("service"), "instance",
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* and "realm" and a key version number "kvno", and looks in the given
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* "file" for the corresponding entry, and if found, returns the entry's
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* key field in "key".
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*
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* If "instance" contains the string "*", then it will match
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* any instance, and the chosen instance will be copied to that
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* string. For this reason it is important that the there is enough
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* space beyond the "*" to receive the entry.
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*
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* If "kvno" is 0, it is treated as a wild card and the first
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* matching entry regardless of the "vno" field is returned.
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*
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* This routine returns KSUCCESS on success, otherwise KFAILURE.
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*
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* The format of each "srvtab" entry is as follows:
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*
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* Size Variable Field in file
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* ---- -------- -------------
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* string serv server name
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* string inst server instance
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* string realm server realm
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* 1 byte vno server key version #
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* 8 bytes key server's key
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* ... ... ...
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*/
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int
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read_service_key(const char *service, /* Service Name */
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char *instance, /* Instance name or "*" */
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const char *realm, /* Realm */
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int kvno, /* Key version number */
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const char *file, /* Filename */
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void *key) /* Pointer to key to be filled in */
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{
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char serv[SNAME_SZ];
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char inst[INST_SZ];
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char rlm[REALM_SZ];
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unsigned char vno; /* Key version number */
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int wcard;
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int stab;
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if ((stab = open(file, O_RDONLY, 0)) < 0)
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return(KFAILURE);
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wcard = (instance[0] == '*') && (instance[1] == '\0');
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while (getst(stab,serv,SNAME_SZ) > 0) { /* Read sname */
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getst(stab,inst,INST_SZ); /* Instance */
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getst(stab,rlm,REALM_SZ); /* Realm */
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/* Vers number */
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if (read(stab, &vno, 1) != 1) {
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close(stab);
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return(KFAILURE);
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}
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/* Key */
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if (read(stab,key,8) != 8) {
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close(stab);
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return(KFAILURE);
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}
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/* Is this the right service */
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if (strcmp(serv,service))
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continue;
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/* How about instance */
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if (!wcard && strcmp(inst,instance))
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continue;
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if (wcard) {
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strcpy_truncate (instance, inst, INST_SZ);
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}
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/* Is this the right realm */
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if (strcmp(rlm,realm))
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continue;
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/* How about the key version number */
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if (kvno && kvno != (int) vno)
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continue;
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close(stab);
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return(KSUCCESS);
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}
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/* Can't find the requested service */
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close(stab);
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return(KFAILURE);
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}
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