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/*
* Copyright 1986, 1987, 1988 by the Massachusetts Institute
* of Technology.
* For copying and distribution information, please see the file
* <Copyright.MIT>.
*
* This routine constructs a Kerberos 'private msg', i.e.
* cryptographically sealed with a private session key.
*
* Note-- bcopy is used to avoid alignment problems on IBM RT.
*
* Note-- It's too bad that it did a long int compare on the RT before.
*
* Returns either < 0 ===> error, or resulting size of message
*
* Steve Miller Project Athena MIT/DEC
*
* from: mk_priv.c,v 4.13 89/03/22 14:48:59 jtkohl Exp $
* $FreeBSD$
*/
#if 0
#ifndef lint
static char rcsid[] =
"$FreeBSD$";
#endif /* lint */
#endif
/* system include files */
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/time.h>
/* application include files */
#include <des.h>
#include <krb.h>
#include <prot.h>
#include "lsb_addr_comp.h"
extern char *errmsg();
extern int errno;
extern int krb_debug;
/* static storage */
static u_long c_length;
static struct timeval msg_time;
static u_char msg_time_5ms;
static long msg_time_sec;
/*
* krb_mk_priv() constructs an AUTH_MSG_PRIVATE message. It takes
* some user data "in" of "length" bytes and creates a packet in "out"
* consisting of the user data, a timestamp, and the sender's network
* address.
#ifndef NOENCRYTION
* The packet is encrypted by pcbc_encrypt(), using the given
* "key" and "schedule".
#endif
* The length of the resulting packet "out" is
* returned.
*
* It is similar to krb_mk_safe() except for the additional key
* schedule argument "schedule" and the fact that the data is encrypted
* rather than appended with a checksum. Also, the protocol version
* number is "private_msg_ver", defined in krb_rd_priv.c, rather than
* KRB_PROT_VERSION, defined in "krb.h".
*
* The "out" packet consists of:
*
* Size Variable Field
* ---- -------- -----
*
* 1 byte private_msg_ver protocol version number
* 1 byte AUTH_MSG_PRIVATE | message type plus local
* HOST_BYTE_ORDER byte order in low bit
*
* 4 bytes c_length length of data
#ifndef NOENCRYPT
* we encrypt from here with pcbc_encrypt
#endif
*
* 4 bytes length length of user data
* length in user data
* 1 byte msg_time_5ms timestamp milliseconds
* 4 bytes sender->sin.addr.s_addr sender's IP address
*
* 4 bytes msg_time_sec or timestamp seconds with
* -msg_time_sec direction in sign bit
*
* 0<=n<=7 bytes pad to 8 byte multiple zeroes
*/
long krb_mk_priv(in,out,length,schedule,key,sender,receiver)
u_char *in; /* application data */
u_char *out; /* put msg here, leave room for
* header! breaks if in and out
* (header stuff) overlap */
u_long length; /* of in data */
Key_schedule schedule; /* precomputed key schedule */
C_Block key; /* encryption key for seed and ivec */
struct sockaddr_in *sender; /* sender address */
struct sockaddr_in *receiver; /* receiver address */
{
register u_char *p,*q;
static u_char *c_length_ptr;
extern int private_msg_ver; /* in krb_rd_priv.c */
/*
* get the current time to use instead of a sequence #, since
* process lifetime may be shorter than the lifetime of a session
* key.
*/
if (gettimeofday(&msg_time,(struct timezone *)0)) {
return -1;
}
msg_time_sec = (long) msg_time.tv_sec;
msg_time_5ms = msg_time.tv_usec/5000; /* 5ms quanta */
p = out;
*p++ = private_msg_ver;
*p++ = AUTH_MSG_PRIVATE | HOST_BYTE_ORDER;
/* calculate cipher length */
c_length_ptr = p;
p += sizeof(c_length);
q = p;
/* stuff input length */
bcopy((char *)&length,(char *)p,sizeof(length));
p += sizeof(length);
#ifdef NOENCRYPTION
/* make all the stuff contiguous for checksum */
#else
/* make all the stuff contiguous for checksum and encryption */
#endif
bcopy((char *)in,(char *)p,(int) length);
p += length;
/* stuff time 5ms */
bcopy((char *)&msg_time_5ms,(char *)p,sizeof(msg_time_5ms));
p += sizeof(msg_time_5ms);
/* stuff source address */
bcopy((char *)&sender->sin_addr.s_addr,(char *)p,
sizeof(sender->sin_addr.s_addr));
p += sizeof(sender->sin_addr.s_addr);
/*
* direction bit is the sign bit of the timestamp. Ok
* until 2038??
*/
/* For compatibility with broken old code, compares are done in VAX
byte order (LSBFIRST) */
if (lsb_net_ulong_less(sender->sin_addr.s_addr, /* src < recv */
receiver->sin_addr.s_addr)==-1)
msg_time_sec = -msg_time_sec;
else if (lsb_net_ulong_less(sender->sin_addr.s_addr,
receiver->sin_addr.s_addr)==0)
if (lsb_net_ushort_less(sender->sin_port,receiver->sin_port) == -1)
msg_time_sec = -msg_time_sec;
/* stuff time sec */
bcopy((char *)&msg_time_sec,(char *)p,sizeof(msg_time_sec));
p += sizeof(msg_time_sec);
/*
* All that for one tiny bit! Heaven help those that talk to
* themselves.
*/
#ifdef notdef
/*
* calculate the checksum of the length, address, sequence, and
* inp data
*/
cksum = quad_cksum(q,NULL,p-q,0,key);
if (krb_debug)
printf("\ncksum = %u",cksum);
/* stuff checksum */
bcopy((char *) &cksum,(char *) p,sizeof(cksum));
p += sizeof(cksum);
#endif
/*
* All the data have been assembled, compute length
*/
c_length = p - q;
c_length = ((c_length + sizeof(C_Block) -1)/sizeof(C_Block)) *
sizeof(C_Block);
/* stuff the length */
bcopy((char *) &c_length,(char *)c_length_ptr,sizeof(c_length));
#ifndef NOENCRYPTION
pcbc_encrypt((C_Block *)q,(C_Block *)q,(long)(p-q),schedule,(C_Block *)key,
ENCRYPT);
#endif /* NOENCRYPTION */
return (q - out + c_length); /* resulting size */
}
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