rd_safe.c revision 72445
155682Smarkm/* 272445Sassar * Copyright (c) 1997 - 2001 Kungliga Tekniska H�gskolan 355682Smarkm * (Royal Institute of Technology, Stockholm, Sweden). 455682Smarkm * All rights reserved. 555682Smarkm * 655682Smarkm * Redistribution and use in source and binary forms, with or without 755682Smarkm * modification, are permitted provided that the following conditions 855682Smarkm * are met: 955682Smarkm * 1055682Smarkm * 1. Redistributions of source code must retain the above copyright 1155682Smarkm * notice, this list of conditions and the following disclaimer. 1255682Smarkm * 1355682Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1455682Smarkm * notice, this list of conditions and the following disclaimer in the 1555682Smarkm * documentation and/or other materials provided with the distribution. 1655682Smarkm * 1755682Smarkm * 3. Neither the name of the Institute nor the names of its contributors 1855682Smarkm * may be used to endorse or promote products derived from this software 1955682Smarkm * without specific prior written permission. 2055682Smarkm * 2155682Smarkm * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 2255682Smarkm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2355682Smarkm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2455682Smarkm * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 2555682Smarkm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2655682Smarkm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2755682Smarkm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2855682Smarkm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2955682Smarkm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3055682Smarkm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3155682Smarkm * SUCH DAMAGE. 3255682Smarkm */ 3355682Smarkm 3455682Smarkm#include <krb5_locl.h> 3555682Smarkm 3672445SassarRCSID("$Id: rd_safe.c,v 1.23 2001/01/19 04:25:37 assar Exp $"); 3755682Smarkm 3855682Smarkmstatic krb5_error_code 3955682Smarkmverify_checksum(krb5_context context, 4055682Smarkm krb5_auth_context auth_context, 4155682Smarkm KRB_SAFE *safe) 4255682Smarkm{ 4355682Smarkm krb5_error_code ret; 4455682Smarkm u_char *buf; 4555682Smarkm size_t buf_size; 4655682Smarkm size_t len; 4755682Smarkm Checksum c; 4855682Smarkm krb5_crypto crypto; 4955682Smarkm 5055682Smarkm c = safe->cksum; 5155682Smarkm safe->cksum.cksumtype = 0; 5255682Smarkm safe->cksum.checksum.data = NULL; 5355682Smarkm safe->cksum.checksum.length = 0; 5455682Smarkm 5555682Smarkm 5655682Smarkm buf_size = length_KRB_SAFE(safe); 5755682Smarkm buf = malloc(buf_size); 5855682Smarkm 5955682Smarkm if (buf == NULL) { 6055682Smarkm ret = ENOMEM; 6155682Smarkm goto out; 6255682Smarkm } 6355682Smarkm 6455682Smarkm ret = encode_KRB_SAFE (buf + buf_size - 1, 6555682Smarkm buf_size, 6655682Smarkm safe, 6755682Smarkm &len); 6872445Sassar ret = krb5_crypto_init(context, auth_context->keyblock, 0, &crypto); 6972445Sassar if (ret) 7072445Sassar goto out; 7155682Smarkm ret = krb5_verify_checksum (context, 7255682Smarkm crypto, 7355682Smarkm KRB5_KU_KRB_SAFE_CKSUM, 7455682Smarkm buf + buf_size - len, 7555682Smarkm len, 7655682Smarkm &c); 7755682Smarkm krb5_crypto_destroy(context, crypto); 7855682Smarkmout: 7955682Smarkm safe->cksum = c; 8055682Smarkm free (buf); 8155682Smarkm return ret; 8255682Smarkm} 8355682Smarkm 8455682Smarkmkrb5_error_code 8555682Smarkmkrb5_rd_safe(krb5_context context, 8655682Smarkm krb5_auth_context auth_context, 8755682Smarkm const krb5_data *inbuf, 8855682Smarkm krb5_data *outbuf, 8955682Smarkm /*krb5_replay_data*/ void *outdata) 9055682Smarkm{ 9155682Smarkm krb5_error_code ret; 9255682Smarkm KRB_SAFE safe; 9355682Smarkm size_t len; 9455682Smarkm 9555682Smarkm ret = decode_KRB_SAFE (inbuf->data, inbuf->length, &safe, &len); 9655682Smarkm if (ret) 9755682Smarkm return ret; 9855682Smarkm if (safe.pvno != 5) { 9955682Smarkm ret = KRB5KRB_AP_ERR_BADVERSION; 10055682Smarkm goto failure; 10155682Smarkm } 10255682Smarkm if (safe.msg_type != krb_safe) { 10355682Smarkm ret = KRB5KRB_AP_ERR_MSG_TYPE; 10455682Smarkm goto failure; 10555682Smarkm } 10655682Smarkm if (!krb5_checksum_is_keyed(context, safe.cksum.cksumtype) 10755682Smarkm || !krb5_checksum_is_collision_proof(context, safe.cksum.cksumtype)) { 10855682Smarkm ret = KRB5KRB_AP_ERR_INAPP_CKSUM; 10955682Smarkm goto failure; 11055682Smarkm } 11155682Smarkm 11255682Smarkm /* check sender address */ 11355682Smarkm 11455682Smarkm if (safe.safe_body.s_address 11555682Smarkm && auth_context->remote_address 11655682Smarkm && !krb5_address_compare (context, 11755682Smarkm auth_context->remote_address, 11855682Smarkm safe.safe_body.s_address)) { 11955682Smarkm ret = KRB5KRB_AP_ERR_BADADDR; 12055682Smarkm goto failure; 12155682Smarkm } 12255682Smarkm 12355682Smarkm /* check receiver address */ 12455682Smarkm 12555682Smarkm if (safe.safe_body.r_address 12655682Smarkm && auth_context->local_address 12755682Smarkm && !krb5_address_compare (context, 12855682Smarkm auth_context->local_address, 12955682Smarkm safe.safe_body.r_address)) { 13055682Smarkm ret = KRB5KRB_AP_ERR_BADADDR; 13155682Smarkm goto failure; 13255682Smarkm } 13355682Smarkm 13455682Smarkm /* check timestamp */ 13555682Smarkm if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) { 13657416Smarkm krb5_timestamp sec; 13755682Smarkm 13855682Smarkm krb5_timeofday (context, &sec); 13955682Smarkm 14055682Smarkm if (safe.safe_body.timestamp == NULL || 14155682Smarkm safe.safe_body.usec == NULL || 14255682Smarkm abs(*safe.safe_body.timestamp - sec) > context->max_skew) { 14355682Smarkm ret = KRB5KRB_AP_ERR_SKEW; 14455682Smarkm goto failure; 14555682Smarkm } 14655682Smarkm } 14755682Smarkm /* XXX - check replay cache */ 14855682Smarkm 14972445Sassar /* check sequence number. since MIT krb5 cannot generate a sequence 15072445Sassar number of zero but instead generates no sequence number, we accept that 15172445Sassar */ 15272445Sassar 15355682Smarkm if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) { 15472445Sassar if ((safe.safe_body.seq_number == NULL 15572445Sassar && auth_context->remote_seqnumber != 0) 15672445Sassar || (safe.safe_body.seq_number != NULL 15772445Sassar && *safe.safe_body.seq_number != 15872445Sassar auth_context->remote_seqnumber)) { 15955682Smarkm ret = KRB5KRB_AP_ERR_BADORDER; 16055682Smarkm goto failure; 16155682Smarkm } 16272445Sassar auth_context->remote_seqnumber++; 16355682Smarkm } 16455682Smarkm 16555682Smarkm ret = verify_checksum (context, auth_context, &safe); 16655682Smarkm if (ret) 16755682Smarkm goto failure; 16855682Smarkm 16955682Smarkm outbuf->length = safe.safe_body.user_data.length; 17055682Smarkm outbuf->data = malloc(outbuf->length); 17155682Smarkm if (outbuf->data == NULL) { 17255682Smarkm ret = ENOMEM; 17355682Smarkm goto failure; 17455682Smarkm } 17555682Smarkm memcpy (outbuf->data, safe.safe_body.user_data.data, outbuf->length); 17655682Smarkm free_KRB_SAFE (&safe); 17755682Smarkm return 0; 17855682Smarkmfailure: 17955682Smarkm free_KRB_SAFE (&safe); 18055682Smarkm return ret; 18155682Smarkm} 182