cf635440ff
These are the start of a lot of work to clean up the FreeBSD eBones code. these changes include, but are not limited to: - Create prototypes for all the library routines - Make all the libraries compile clean with -Wall set - Fix numerous small bugs shown up in the above process - Prepare the code for libdes's removal to secure/ - add register, registerd and make_keypair to the make Lots more will follow in days to come. OK'ed by: rgrimes
279 lines
8.8 KiB
C
279 lines
8.8 KiB
C
/*
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* Copyright 1987, 1988 by the Massachusetts Institute of Technology.
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* For copying and distribution information, please see the file
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* <Copyright.MIT>.
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*
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* from: recvauth.c,v 4.4 90/03/10 19:03:08 jon Exp $";
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* $Id: recvauth.c,v 1.3 1995/07/18 16:39:38 mark Exp $
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*/
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#if 0
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#ifndef lint
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static char rcsid[] =
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"$Id: recvauth.c,v 1.3 1995/07/18 16:39:38 mark Exp $";
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#endif lint
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#endif
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <syslog.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <strings.h>
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#include <krb.h>
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#define KRB_SENDAUTH_VERS "AUTHV0.1" /* MUST be KRB_SENDAUTH_VLEN
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chars */
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/*
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* If the protocol changes, you will need to change the version string
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* and make appropriate changes in krb_sendauth.c
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* be sure to support old versions of krb_sendauth!
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*/
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/*
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* krb_recvauth() reads (and optionally responds to) a message sent
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* using krb_sendauth(). The "options" argument is a bit-field of
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* selected options (see "sendauth.c" for options description).
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* The only option relevant to krb_recvauth() is KOPT_DO_MUTUAL
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* (mutual authentication requested). The "fd" argument supplies
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* a file descriptor to read from (and write to, if mutual authenti-
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* cation is requested).
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*
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* Part of the received message will be a Kerberos ticket sent by the
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* client; this is read into the "ticket" argument. The "service" and
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* "instance" arguments supply the server's Kerberos name. If the
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* "instance" argument is the string "*", it is treated as a wild card
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* and filled in during the krb_rd_req() call (see read_service_key()).
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*
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* The "faddr" and "laddr" give the sending (client) and receiving
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* (local server) network addresses. ("laddr" may be left NULL unless
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* mutual authentication is requested, in which case it must be set.)
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*
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* The authentication information extracted from the message is returned
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* in "kdata". The "filename" argument indicates the file where the
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* server's key can be found. (It is passed on to krb_rd_req().) If
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* left null, the default "/etc/srvtab" will be used.
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*
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* If mutual authentication is requested, the session key schedule must
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* be computed in order to reply; this schedule is returned in the
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* "schedule" argument. A string containing the application version
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* number from the received message is returned in "version", which
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* should be large enough to hold a KRB_SENDAUTH_VLEN-character string.
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*
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* See krb_sendauth() for the format of the received client message.
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*
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* This routine supports another client format, for backward
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* compatibility, consisting of:
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*
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* Size Variable Field
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* ---- -------- -----
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*
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* string tmp_buf, tkt_len length of ticket, in
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* ascii
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*
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* char ' ' (space char) separator
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*
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* tkt_len ticket->dat the ticket
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*
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* This old-style version does not support mutual authentication.
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*
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* krb_recvauth() first reads the protocol version string from the
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* given file descriptor. If it doesn't match the current protocol
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* version (KRB_SENDAUTH_VERS), the old-style format is assumed. In
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* that case, the string of characters up to the first space is read
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* and interpreted as the ticket length, then the ticket is read.
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*
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* If the first string did match KRB_SENDAUTH_VERS, krb_recvauth()
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* next reads the application protocol version string. Then the
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* ticket length and ticket itself are read.
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*
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* The ticket is decrypted and checked by the call to krb_rd_req().
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* If no mutual authentication is required, the result of the
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* krb_rd_req() call is retured by this routine. If mutual authenti-
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* cation is required, a message in the following format is returned
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* on "fd":
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*
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* Size Variable Field
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* ---- -------- -----
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*
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* 4 bytes tkt_len length of ticket or -1
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* if error occurred
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*
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* priv_len tmp_buf "private" message created
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* by krb_mk_priv() which
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* contains the incremented
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* checksum sent by the client
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* encrypted in the session
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* key. (This field is not
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* present in case of error.)
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*
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* If all goes well, KSUCCESS is returned; otherwise KFAILURE or some
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* other error code is returned.
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*/
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#ifndef max
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#define max(a,b) (((a) > (b)) ? (a) : (b))
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#endif /* max */
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int
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krb_recvauth(long options, int fd, KTEXT ticket, char *service, char *instance,
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struct sockaddr_in *faddr, struct sockaddr_in *laddr, AUTH_DAT *kdata,
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char *filename, des_key_schedule schedule, char *version)
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{
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int i, cc, old_vers = 0;
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char krb_vers[KRB_SENDAUTH_VLEN + 1]; /* + 1 for the null terminator */
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char *cp = NULL;
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int rem;
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long tkt_len, priv_len;
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u_long cksum;
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u_char tmp_buf[MAX_KTXT_LEN+max(KRB_SENDAUTH_VLEN+1,21)];
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/* read the protocol version number */
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if (krb_net_read(fd, krb_vers, KRB_SENDAUTH_VLEN) !=
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KRB_SENDAUTH_VLEN)
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return(errno);
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krb_vers[KRB_SENDAUTH_VLEN] = '\0';
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/* check version string */
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if (strcmp(krb_vers,KRB_SENDAUTH_VERS)) {
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/* Assume the old version of sendkerberosdata: send ascii
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length, ' ', and ticket. */
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if (options & KOPT_DO_MUTUAL)
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return(KFAILURE); /* XXX can't do old style with mutual auth */
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old_vers = 1;
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/* copy what we have read into tmp_buf */
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(void) bcopy(krb_vers, (char *) tmp_buf, KRB_SENDAUTH_VLEN);
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/* search for space, and make it a null */
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for (i = 0; i < KRB_SENDAUTH_VLEN; i++)
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if (tmp_buf[i]== ' ') {
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tmp_buf[i] = '\0';
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/* point cp to the beginning of the real ticket */
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cp = (char *) &tmp_buf[i+1];
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break;
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}
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if (i == KRB_SENDAUTH_VLEN)
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/* didn't find the space, keep reading to find it */
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for (; i<20; i++) {
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if (read(fd, (char *)&tmp_buf[i], 1) != 1) {
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return(KFAILURE);
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}
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if (tmp_buf[i] == ' ') {
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tmp_buf[i] = '\0';
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/* point cp to the beginning of the real ticket */
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cp = (char *) &tmp_buf[i+1];
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break;
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}
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}
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tkt_len = (long) atoi((char *) tmp_buf);
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/* sanity check the length */
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if ((i==20)||(tkt_len<=0)||(tkt_len>MAX_KTXT_LEN))
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return(KFAILURE);
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if (i < KRB_SENDAUTH_VLEN) {
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/* since we already got the space, and part of the ticket,
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we read fewer bytes to get the rest of the ticket */
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if (krb_net_read(fd, (char *)(tmp_buf+KRB_SENDAUTH_VLEN),
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(int) (tkt_len - KRB_SENDAUTH_VLEN + 1 + i))
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!= (int)(tkt_len - KRB_SENDAUTH_VLEN + 1 + i))
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return(errno);
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} else {
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if (krb_net_read(fd, (char *)(tmp_buf+i), (int)tkt_len) !=
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(int) tkt_len)
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return(errno);
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}
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ticket->length = tkt_len;
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/* copy the ticket into the struct */
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(void) bcopy(cp, (char *) ticket->dat, ticket->length);
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} else {
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/* read the application version string */
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if (krb_net_read(fd, version, KRB_SENDAUTH_VLEN) !=
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KRB_SENDAUTH_VLEN)
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return(errno);
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version[KRB_SENDAUTH_VLEN] = '\0';
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/* get the length of the ticket */
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if (krb_net_read(fd, (char *)&tkt_len, sizeof(tkt_len)) !=
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sizeof(tkt_len))
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return(errno);
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/* sanity check */
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ticket->length = ntohl((unsigned long)tkt_len);
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if ((ticket->length <= 0) || (ticket->length > MAX_KTXT_LEN)) {
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if (options & KOPT_DO_MUTUAL) {
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rem = KFAILURE;
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goto mutual_fail;
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} else
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return(KFAILURE); /* XXX there may still be junk on the fd? */
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}
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/* read the ticket */
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if (krb_net_read(fd, (char *) ticket->dat, ticket->length)
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!= ticket->length)
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return(errno);
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}
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/*
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* now have the ticket. decrypt it to get the authenticated
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* data.
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*/
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rem = krb_rd_req(ticket,service,instance,faddr->sin_addr.s_addr,
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kdata,filename);
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if (old_vers) return(rem); /* XXX can't do mutual with old client */
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/* if we are doing mutual auth, compose a response */
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if (options & KOPT_DO_MUTUAL) {
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if (rem != KSUCCESS)
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/* the krb_rd_req failed */
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goto mutual_fail;
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/* add one to the (formerly) sealed checksum, and re-seal it
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for return to the client */
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cksum = kdata->checksum + 1;
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cksum = htonl(cksum);
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#ifndef NOENCRYPTION
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key_sched((des_cblock *)kdata->session,schedule);
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#endif
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priv_len = krb_mk_priv((unsigned char *)&cksum,
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tmp_buf,
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(unsigned long) sizeof(cksum),
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schedule,
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kdata->session,
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laddr,
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faddr);
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if (priv_len < 0) {
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/* re-sealing failed; notify the client */
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rem = KFAILURE; /* XXX */
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mutual_fail:
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priv_len = -1;
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tkt_len = htonl((unsigned long) priv_len);
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/* a length of -1 is interpreted as an authentication
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failure by the client */
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if ((cc = krb_net_write(fd, (char *)&tkt_len, sizeof(tkt_len)))
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!= sizeof(tkt_len))
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return(cc);
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return(rem);
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} else {
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/* re-sealing succeeded, send the private message */
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tkt_len = htonl((unsigned long)priv_len);
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if ((cc = krb_net_write(fd, (char *)&tkt_len, sizeof(tkt_len)))
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!= sizeof(tkt_len))
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return(cc);
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if ((cc = krb_net_write(fd, (char *)tmp_buf, (int) priv_len))
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!= (int) priv_len)
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return(cc);
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}
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}
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return(rem);
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}
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