179 lines
5.8 KiB
C
179 lines
5.8 KiB
C
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/*
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* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska H<EFBFBD>gskolan
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the Kungliga Tekniska
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* H<EFBFBD>gskolan and its contributors.
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*
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* 4. 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_safe.c,v 1.24 1997/04/19 23:18:20 joda Exp $");
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/* application include files */
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#include "lsb_addr_comp.h"
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/* Generate two checksums in the given byteorder of the data, one
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* new-form and one old-form. It has to be done this way to be
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* compatible with the old version of des_quad_cksum.
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*/
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/* des_quad_chsum-type; 0 == unknown, 1 == new PL10++, 2 == old */
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int dqc_type = DES_QUAD_DEFAULT;
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void
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fixup_quad_cksum(void *start, size_t len, des_cblock *key,
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void *new_checksum, void *old_checksum, int little)
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{
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des_quad_cksum((des_cblock*)start, (des_cblock*)new_checksum, len, 2, key);
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if(HOST_BYTE_ORDER){
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if(little){
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memcpy(old_checksum, new_checksum, 16);
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}else{
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u_int32_t *tmp = (u_int32_t*)new_checksum;
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memcpy(old_checksum, new_checksum, 16);
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swap_u_16(old_checksum);
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swap_u_long(tmp[0]);
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swap_u_long(tmp[1]);
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swap_u_long(tmp[2]);
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swap_u_long(tmp[3]);
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}
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}else{
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if(little){
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u_int32_t *tmp = (u_int32_t*)new_checksum;
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swap_u_long(tmp[0]);
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swap_u_long(tmp[1]);
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swap_u_long(tmp[2]);
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swap_u_long(tmp[3]);
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memcpy(old_checksum, new_checksum, 16);
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}else{
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u_int32_t tmp[4];
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tmp[0] = ((u_int32_t*)new_checksum)[3];
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tmp[1] = ((u_int32_t*)new_checksum)[2];
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tmp[2] = ((u_int32_t*)new_checksum)[1];
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tmp[3] = ((u_int32_t*)new_checksum)[0];
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memcpy(old_checksum, tmp, 16);
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}
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}
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}
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/*
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* krb_rd_safe() checks the integrity of an AUTH_MSG_SAFE message.
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* Given the message received, "in", the length of that message,
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* "in_length", the "key" to compute the checksum with, and the
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* network addresses of the "sender" and "receiver" of the message,
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* krb_rd_safe() returns RD_AP_OK if message is okay, otherwise
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* some error code.
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*
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* The message data retrieved from "in" is returned in the structure
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* "m_data". The pointer to the application data (m_data->app_data)
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* refers back to the appropriate place in "in".
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*
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* See the file "mk_safe.c" for the format of the AUTH_MSG_SAFE
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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_safe(void *in, u_int32_t in_length, 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, *start;
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unsigned char pvno, type;
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int little_endian;
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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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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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if(type != AUTH_MSG_SAFE)
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return RD_AP_MSG_TYPE;
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start = p;
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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 + 31 > 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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delta_t = abs((int)((long) tv.tv_sec - m_data->time_sec));
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if (delta_t > CLOCK_SKEW) return RD_AP_TIME;
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/*
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* caller must check timestamps for proper order and replays, since
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* server might have multiple clients each with its own timestamps
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* and we don't assume tightly synchronized clocks.
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*/
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{
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unsigned char new_checksum[16];
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unsigned char old_checksum[16];
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fixup_quad_cksum(start, p - start, key,
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new_checksum, old_checksum, little_endian);
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if((dqc_type == DES_QUAD_GUESS || dqc_type == DES_QUAD_NEW) &&
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memcmp(new_checksum, p, 16) == 0)
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dqc_type = DES_QUAD_NEW;
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else if((dqc_type == DES_QUAD_GUESS || dqc_type == DES_QUAD_OLD) &&
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memcmp(old_checksum, p, 16) == 0)
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dqc_type = DES_QUAD_OLD;
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else
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return RD_AP_MODIFIED;
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}
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return KSUCCESS;
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}
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