125 lines
4.2 KiB
C
125 lines
4.2 KiB
C
/*
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* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "krb_locl.h"
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RCSID("$Id: rd_priv.c,v 1.27 1999/12/02 16:58:43 joda Exp $");
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/* application include files */
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#include "krb-archaeology.h"
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/*
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* krb_rd_priv() decrypts and checks the integrity of an
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* AUTH_MSG_PRIVATE message. Given the message received, "in",
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* the length of that message, "in_length", the key "schedule"
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* and "key", and the network addresses of the
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* "sender" and "receiver" of the message, krb_rd_safe() returns
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* RD_AP_OK if the message is okay, otherwise some error code.
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*
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* The message data retrieved from "in" are returned in the structure
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* "m_data". The pointer to the application data
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* (m_data->app_data) refers back to the appropriate place in "in".
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*
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* See the file "mk_priv.c" for the format of the AUTH_MSG_PRIVATE
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* message. The structure containing the extracted message
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* information, MSG_DAT, is defined in "krb.h".
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*/
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int32_t
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krb_rd_priv(void *in, u_int32_t in_length,
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struct des_ks_struct *schedule, des_cblock *key,
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struct sockaddr_in *sender, struct sockaddr_in *receiver,
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MSG_DAT *m_data)
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{
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unsigned char *p = (unsigned char*)in;
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int little_endian;
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u_int32_t clen;
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struct timeval tv;
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u_int32_t src_addr;
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int delta_t;
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unsigned char pvno, type;
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pvno = *p++;
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if(pvno != KRB_PROT_VERSION)
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return RD_AP_VERSION;
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type = *p++;
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little_endian = type & 1;
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type &= ~1;
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p += krb_get_int(p, &clen, 4, little_endian);
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if(clen + 2 > in_length)
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return RD_AP_MODIFIED;
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des_pcbc_encrypt((des_cblock*)p, (des_cblock*)p, clen,
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schedule, key, DES_DECRYPT);
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p += krb_get_int(p, &m_data->app_length, 4, little_endian);
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if(m_data->app_length + 17 > in_length)
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return RD_AP_MODIFIED;
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m_data->app_data = p;
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p += m_data->app_length;
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m_data->time_5ms = *p++;
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p += krb_get_address(p, &src_addr);
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if (!krb_equiv(src_addr, sender->sin_addr.s_addr))
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return RD_AP_BADD;
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p += krb_get_int(p, (u_int32_t *)&m_data->time_sec, 4, little_endian);
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m_data->time_sec = lsb_time(m_data->time_sec, sender, receiver);
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gettimeofday(&tv, NULL);
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/* check the time integrity of the msg */
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delta_t = abs((int)((long) tv.tv_sec - m_data->time_sec));
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if (delta_t > CLOCK_SKEW)
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return RD_AP_TIME;
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if (krb_debug)
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krb_warning("delta_t = %d\n", (int) delta_t);
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/*
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* caller must check timestamps for proper order and
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* replays, since server might have multiple clients
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* each with its own timestamps and we don't assume
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* tightly synchronized clocks.
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*/
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return KSUCCESS;
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}
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