+/*
+ * $Source: /mit/kerberos/src/lib/krb/RCS/mk_priv.c,v $
+ * $Author: jtkohl $
+ *
+ * Copyright 1986, 1987, 1988 by the Massachusetts Institute
+ * of Technology.
+ *
+ * For copying and distribution information, please see the file
+ * <mit-copyright.h>.
+ *
+ * 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
+ */
+
+#ifndef lint
+static char *rcsid_mk_priv_c=
+"$Header: mk_priv.c,v 4.13 89/03/22 14:48:59 jtkohl Exp $";
+#endif /* lint */
+
+#include <mit-copyright.h>
+
+/* system include files */
+#include <stdio.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
+ *
+#ifdef NOENCRYPTION
+ * 4 bytes c_length length of data
+#else
+ * 4 bytes c_length length of encrypted data
+ *
+ * ===================== begin 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
+#ifndef NOENCRYPTION
+ * (done by pcbc_encrypt())
+ *
+ * ======================= end encrypt ================================
+#endif
+ */
+
+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);
+
+#ifndef NOENCRYPTION
+ /* start for encrypted stuff */
+#endif
+ 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
+
+#ifdef NOENCRYPTION
+ /*
+ * All the data have been assembled, compute length
+ */
+#else
+ /*
+ * All the data have been assembled, compute length and encrypt
+ * starting with the length, data, and timestamps use the key as
+ * an ivec.
+ */
+#endif
+
+ 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, pad as needed, use key as ivec */
+ pcbc_encrypt((C_Block *) q,(C_Block *) q, (long) (p-q), schedule,
+ key, ENCRYPT);
+#endif /* NOENCRYPTION */
+
+ return (q - out + c_length); /* resulting size */
+}
projects / unix-history / commitdiff