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/*
* Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb5_locl.h"
static krb5_error_code
verify_checksum(krb5_context context,
krb5_auth_context auth_context,
KRB_SAFE *safe)
{
krb5_error_code ret;
u_char *buf;
size_t buf_size;
size_t len = 0;
Checksum c;
krb5_crypto crypto;
krb5_keyblock *key;
c = safe->cksum;
safe->cksum.cksumtype = 0;
safe->cksum.checksum.data = NULL;
safe->cksum.checksum.length = 0;
ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, safe, &len, ret);
if(ret)
return ret;
if(buf_size != len)
krb5_abortx(context, "internal error in ASN.1 encoder");
if (auth_context->remote_subkey)
key = auth_context->remote_subkey;
else if (auth_context->local_subkey)
key = auth_context->local_subkey;
else
key = auth_context->keyblock;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
goto out;
ret = krb5_verify_checksum (context,
crypto,
KRB5_KU_KRB_SAFE_CKSUM,
buf + buf_size - len,
len,
&c);
krb5_crypto_destroy(context, crypto);
out:
safe->cksum = c;
free (buf);
return ret;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_safe(krb5_context context,
krb5_auth_context auth_context,
const krb5_data *inbuf,
krb5_data *outbuf,
krb5_replay_data *outdata)
{
krb5_error_code ret;
KRB_SAFE safe;
size_t len;
krb5_data_zero(outbuf);
if ((auth_context->flags &
(KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)))
{
if (outdata == NULL) {
krb5_set_error_message(context, KRB5_RC_REQUIRED,
N_("rd_safe: need outdata "
"to return data", ""));
return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
}
/* if these fields are not present in the safe-part, silently
return zero */
memset(outdata, 0, sizeof(*outdata));
}
ret = decode_KRB_SAFE (inbuf->data, inbuf->length, &safe, &len);
if (ret)
return ret;
if (safe.pvno != 5) {
ret = KRB5KRB_AP_ERR_BADVERSION;
krb5_clear_error_message (context);
goto failure;
}
if (safe.msg_type != krb_safe) {
ret = KRB5KRB_AP_ERR_MSG_TYPE;
krb5_clear_error_message (context);
goto failure;
}
if (!krb5_checksum_is_keyed(context, safe.cksum.cksumtype)
|| !krb5_checksum_is_collision_proof(context, safe.cksum.cksumtype)) {
ret = KRB5KRB_AP_ERR_INAPP_CKSUM;
krb5_clear_error_message (context);
goto failure;
}
/* check sender address */
if (safe.safe_body.s_address
&& auth_context->remote_address
&& !krb5_address_compare (context,
auth_context->remote_address,
safe.safe_body.s_address)) {
ret = KRB5KRB_AP_ERR_BADADDR;
krb5_clear_error_message (context);
goto failure;
}
/* check receiver address */
if (safe.safe_body.r_address
&& auth_context->local_address
&& !krb5_address_compare (context,
auth_context->local_address,
safe.safe_body.r_address)) {
ret = KRB5KRB_AP_ERR_BADADDR;
krb5_clear_error_message (context);
goto failure;
}
/* check timestamp */
if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
krb5_timestamp sec;
krb5_timeofday (context, &sec);
if (safe.safe_body.timestamp == NULL ||
safe.safe_body.usec == NULL ||
labs(*safe.safe_body.timestamp - sec) > context->max_skew) {
ret = KRB5KRB_AP_ERR_SKEW;
krb5_clear_error_message (context);
goto failure;
}
}
/* XXX - check replay cache */
/* check sequence number. since MIT krb5 cannot generate a sequence
number of zero but instead generates no sequence number, we accept that
*/
if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
if ((safe.safe_body.seq_number == NULL
&& auth_context->remote_seqnumber != 0)
|| (safe.safe_body.seq_number != NULL
&& *safe.safe_body.seq_number !=
auth_context->remote_seqnumber)) {
ret = KRB5KRB_AP_ERR_BADORDER;
krb5_clear_error_message (context);
goto failure;
}
auth_context->remote_seqnumber++;
}
ret = verify_checksum (context, auth_context, &safe);
if (ret)
goto failure;
outbuf->length = safe.safe_body.user_data.length;
outbuf->data = malloc(outbuf->length);
if (outbuf->data == NULL && outbuf->length != 0) {
ret = krb5_enomem(context);
krb5_data_zero(outbuf);
goto failure;
}
memcpy (outbuf->data, safe.safe_body.user_data.data, outbuf->length);
if ((auth_context->flags &
(KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
if(safe.safe_body.timestamp)
outdata->timestamp = *safe.safe_body.timestamp;
if(safe.safe_body.usec)
outdata->usec = *safe.safe_body.usec;
if(safe.safe_body.seq_number)
outdata->seq = *safe.safe_body.seq_number;
}
failure:
free_KRB_SAFE (&safe);
return ret;
}
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