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Annotation of 43BSDReno/kerberosIV/krb/read_service_key.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * $Source: /usr/src/kerberosIV/krb/RCS/read_service_key.c,v $
                      3:  * $Author: kfall $
                      4:  *
                      5:  * Copyright 1985, 1986, 1987, 1988 by the Massachusetts Institute
                      6:  * of Technology.
                      7:  *
                      8:  * For copying and distribution information, please see the file
                      9:  * <mit-copyright.h>.
                     10:  */
                     11: 
                     12: #ifndef lint
                     13: static char *rcsid_read_service_key_c =
                     14: "$Id: read_service_key.c,v 4.10 90/06/25 20:57:14 kfall Exp $";
                     15: #endif /* lint */
                     16: 
                     17: #include <mit-copyright.h>
                     18: #include <des.h>
                     19: #include <krb.h>
                     20: #include <stdio.h>
                     21: #include <strings.h>
                     22: 
                     23: /*
                     24:  * The private keys for servers on a given host are stored in a
                     25:  * "srvtab" file (typically "/etc/srvtab").  This routine extracts
                     26:  * a given server's key from the file.
                     27:  *
                     28:  * read_service_key() takes the server's name ("service"), "instance",
                     29:  * and "realm" and a key version number "kvno", and looks in the given
                     30:  * "file" for the corresponding entry, and if found, returns the entry's
                     31:  * key field in "key".
                     32:  * 
                     33:  * If "instance" contains the string "*", then it will match
                     34:  * any instance, and the chosen instance will be copied to that
                     35:  * string.  For this reason it is important that the there is enough
                     36:  * space beyond the "*" to receive the entry.
                     37:  *
                     38:  * If "kvno" is 0, it is treated as a wild card and the first
                     39:  * matching entry regardless of the "vno" field is returned.
                     40:  *
                     41:  * This routine returns KSUCCESS on success, otherwise KFAILURE.
                     42:  *
                     43:  * The format of each "srvtab" entry is as follows:
                     44:  *
                     45:  * Size                        Variable                Field in file
                     46:  * ----                        --------                -------------
                     47:  * string              serv                    server name
                     48:  * string              inst                    server instance
                     49:  * string              realm                   server realm
                     50:  * 1 byte              vno                     server key version #
                     51:  * 8 bytes             key                     server's key
                     52:  * ...                 ...                     ...
                     53:  */
                     54: 
                     55: 
                     56: /*ARGSUSED */
                     57: read_service_key(service,instance,realm,kvno,file,key)
                     58:     char *service;              /* Service Name */
                     59:     char *instance;             /* Instance name or "*" */
                     60:     char *realm;                /* Realm */
                     61:     int kvno;                   /* Key version number */
                     62:     char *file;                 /* Filename */
                     63:     char *key;                  /* Pointer to key to be filled in */
                     64: {
                     65:     char serv[SNAME_SZ];
                     66:     char inst[INST_SZ];
                     67:     char rlm[REALM_SZ];
                     68:     unsigned char vno;          /* Key version number */
                     69:     int wcard;
                     70: 
                     71:     int stab, open();
                     72: 
                     73:     if ((stab = open(file, 0, 0)) < NULL)
                     74:         return(KFAILURE);
                     75: 
                     76:     wcard = (instance[0] == '*') && (instance[1] == '\0');
                     77: 
                     78:     while(getst(stab,serv,SNAME_SZ) > 0) { /* Read sname */
                     79:         (void) getst(stab,inst,INST_SZ); /* Instance */
                     80:         (void) getst(stab,rlm,REALM_SZ); /* Realm */
                     81:         /* Vers number */
                     82:         if (read(stab,(char *)&vno,1) != 1)
                     83:             return(KFAILURE);
                     84:         /* Key */
                     85:         if (read(stab,key,8) != 8)
                     86:             return(KFAILURE);
                     87:         /* Is this the right service */
                     88:         if (strcmp(serv,service))
                     89:             continue;
                     90:         /* How about instance */
                     91:         if (!wcard && strcmp(inst,instance))
                     92:             continue;
                     93:         if (wcard)
                     94:             (void) strncpy(instance,inst,INST_SZ);
                     95:         /* Is this the right realm */
                     96: #ifdef ATHENA_COMPAT
                     97:        /* XXX For backward compatibility:  if keyfile says "Athena"
                     98:           and caller wants "ATHENA.MIT.EDU", call it a match */
                     99:         if (strcmp(rlm,realm) &&
                    100:            (strcmp(rlm,"Athena") ||
                    101:             strcmp(realm,"ATHENA.MIT.EDU")))
                    102:            continue;
                    103: #else /* ! ATHENA_COMPAT */
                    104:         if (strcmp(rlm,realm)) 
                    105:            continue;
                    106: #endif /* ATHENA_COMPAT */
                    107: 
                    108:         /* How about the key version number */
                    109:         if (kvno && kvno != (int) vno)
                    110:             continue;
                    111: 
                    112:         (void) close(stab);
                    113:         return(KSUCCESS);
                    114:     }
                    115: 
                    116:     /* Can't find the requested service */
                    117:     (void) close(stab);
                    118:     return(KFAILURE);
                    119: }

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