407 lines
11 KiB
C
407 lines
11 KiB
C
/*
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* Copyright (c) 1997 - 2001 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 "gssapi_locl.h"
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RCSID("$Id: unwrap.c,v 1.15 2001/01/29 02:08:58 assar Exp $");
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OM_uint32
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gss_krb5_getsomekey(const gss_ctx_id_t context_handle,
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krb5_keyblock **key)
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{
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/* XXX this is ugly, and probably incorrect... */
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krb5_keyblock *skey;
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krb5_auth_con_getlocalsubkey(gssapi_krb5_context,
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context_handle->auth_context,
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&skey);
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if(skey == NULL)
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krb5_auth_con_getremotesubkey(gssapi_krb5_context,
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context_handle->auth_context,
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&skey);
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if(skey == NULL)
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krb5_auth_con_getkey(gssapi_krb5_context,
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context_handle->auth_context,
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&skey);
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if(skey == NULL)
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return GSS_S_FAILURE;
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*key = skey;
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return 0;
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}
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static OM_uint32
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unwrap_des
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(OM_uint32 * minor_status,
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const gss_ctx_id_t context_handle,
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const gss_buffer_t input_message_buffer,
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gss_buffer_t output_message_buffer,
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int * conf_state,
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gss_qop_t * qop_state,
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krb5_keyblock *key
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)
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{
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u_char *p, *pad;
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size_t len;
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MD5_CTX md5;
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u_char hash[16], seq_data[8];
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des_key_schedule schedule;
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des_cblock deskey;
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des_cblock zero;
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int i;
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int32_t seq_number;
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size_t padlength;
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OM_uint32 ret;
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int cstate;
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p = input_message_buffer->value;
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ret = gssapi_krb5_verify_header (&p,
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input_message_buffer->length,
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"\x02\x01");
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if (ret)
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return ret;
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if (memcmp (p, "\x00\x00", 2) != 0)
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return GSS_S_BAD_SIG;
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p += 2;
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if (memcmp (p, "\x00\x00", 2) == 0) {
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cstate = 1;
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} else if (memcmp (p, "\xFF\xFF", 2) == 0) {
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cstate = 0;
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} else
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return GSS_S_BAD_MIC;
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p += 2;
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if(conf_state != NULL)
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*conf_state = cstate;
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if (memcmp (p, "\xff\xff", 2) != 0)
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return GSS_S_DEFECTIVE_TOKEN;
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p += 2;
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p += 16;
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len = p - (u_char *)input_message_buffer->value;
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if(cstate) {
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/* decrypt data */
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memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
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for (i = 0; i < sizeof(deskey); ++i)
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deskey[i] ^= 0xf0;
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des_set_key (&deskey, schedule);
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memset (&zero, 0, sizeof(zero));
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des_cbc_encrypt ((void *)p,
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(void *)p,
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input_message_buffer->length - len,
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schedule,
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&zero,
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DES_DECRYPT);
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memset (deskey, 0, sizeof(deskey));
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memset (schedule, 0, sizeof(schedule));
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}
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/* check pad */
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pad = (u_char *)input_message_buffer->value + input_message_buffer->length - 1;
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padlength = *pad;
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for (i = padlength; i > 0 && *pad == padlength; i--, pad--)
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;
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if (i != 0)
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return GSS_S_BAD_MIC;
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MD5_Init (&md5);
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MD5_Update (&md5, p - 24, 8);
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MD5_Update (&md5, p, input_message_buffer->length - len);
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MD5_Final (hash, &md5);
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memset (&zero, 0, sizeof(zero));
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memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
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des_set_key (&deskey, schedule);
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des_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
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schedule, &zero);
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if (memcmp (p - 8, hash, 8) != 0)
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return GSS_S_BAD_MIC;
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/* verify sequence number */
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krb5_auth_getremoteseqnumber (gssapi_krb5_context,
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context_handle->auth_context,
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&seq_number);
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seq_data[0] = (seq_number >> 0) & 0xFF;
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seq_data[1] = (seq_number >> 8) & 0xFF;
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seq_data[2] = (seq_number >> 16) & 0xFF;
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seq_data[3] = (seq_number >> 24) & 0xFF;
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memset (seq_data + 4,
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(context_handle->more_flags & LOCAL) ? 0xFF : 0,
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4);
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p -= 16;
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des_set_key (&deskey, schedule);
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des_cbc_encrypt ((void *)p, (void *)p, 8,
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schedule, (des_cblock *)hash, DES_DECRYPT);
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memset (deskey, 0, sizeof(deskey));
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memset (schedule, 0, sizeof(schedule));
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if (memcmp (p, seq_data, 8) != 0) {
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return GSS_S_BAD_MIC;
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}
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krb5_auth_setremoteseqnumber (gssapi_krb5_context,
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context_handle->auth_context,
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++seq_number);
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/* copy out data */
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output_message_buffer->length = input_message_buffer->length
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- len - padlength - 8;
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output_message_buffer->value = malloc(output_message_buffer->length);
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if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
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return GSS_S_FAILURE;
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memcpy (output_message_buffer->value,
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p + 24,
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output_message_buffer->length);
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return GSS_S_COMPLETE;
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}
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static OM_uint32
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unwrap_des3
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(OM_uint32 * minor_status,
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const gss_ctx_id_t context_handle,
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const gss_buffer_t input_message_buffer,
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gss_buffer_t output_message_buffer,
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int * conf_state,
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gss_qop_t * qop_state,
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krb5_keyblock *key
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)
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{
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u_char *p, *pad;
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size_t len;
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u_char seq[8];
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krb5_data seq_data;
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u_char cksum[20];
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int i;
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int32_t seq_number;
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size_t padlength;
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OM_uint32 ret;
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int cstate;
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krb5_crypto crypto;
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Checksum csum;
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int cmp;
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p = input_message_buffer->value;
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ret = gssapi_krb5_verify_header (&p,
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input_message_buffer->length,
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"\x02\x01");
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if (ret)
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return ret;
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if (memcmp (p, "\x04\x00", 2) != 0) /* HMAC SHA1 DES3_KD */
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return GSS_S_BAD_SIG;
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p += 2;
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if (memcmp (p, "\x02\x00", 2) == 0) {
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cstate = 1;
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} else if (memcmp (p, "\xff\xff", 2) == 0) {
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cstate = 0;
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} else
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return GSS_S_BAD_MIC;
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p += 2;
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if(conf_state != NULL)
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*conf_state = cstate;
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if (memcmp (p, "\xff\xff", 2) != 0)
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return GSS_S_DEFECTIVE_TOKEN;
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p += 2;
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p += 28;
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len = p - (u_char *)input_message_buffer->value;
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if(cstate) {
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/* decrypt data */
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krb5_data tmp;
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ret = krb5_crypto_init(gssapi_krb5_context, key,
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ETYPE_DES3_CBC_NONE, &crypto);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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ret = krb5_decrypt(gssapi_krb5_context, crypto, KRB5_KU_USAGE_SEAL,
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p, input_message_buffer->length - len, &tmp);
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krb5_crypto_destroy(gssapi_krb5_context, crypto);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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assert (tmp.length == input_message_buffer->length - len);
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memcpy (p, tmp.data, tmp.length);
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krb5_data_free(&tmp);
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}
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/* check pad */
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pad = (u_char *)input_message_buffer->value + input_message_buffer->length - 1;
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padlength = *pad;
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for (i = padlength; i > 0 && *pad == padlength; i--, pad--)
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;
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if (i != 0)
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return GSS_S_BAD_MIC;
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/* verify sequence number */
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krb5_auth_getremoteseqnumber (gssapi_krb5_context,
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context_handle->auth_context,
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&seq_number);
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seq[0] = (seq_number >> 0) & 0xFF;
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seq[1] = (seq_number >> 8) & 0xFF;
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seq[2] = (seq_number >> 16) & 0xFF;
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seq[3] = (seq_number >> 24) & 0xFF;
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memset (seq + 4,
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(context_handle->more_flags & LOCAL) ? 0xFF : 0,
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4);
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p -= 28;
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ret = krb5_crypto_init(gssapi_krb5_context, key,
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ETYPE_DES3_CBC_NONE_IVEC, &crypto);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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{
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des_cblock ivec;
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memcpy(&ivec, p + 8, 8);
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ret = krb5_decrypt_ivec (gssapi_krb5_context,
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crypto,
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KRB5_KU_USAGE_SEQ,
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p, 8, &seq_data,
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&ivec);
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}
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krb5_crypto_destroy (gssapi_krb5_context, crypto);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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if (seq_data.length != 8) {
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krb5_data_free (&seq_data);
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return GSS_S_BAD_MIC;
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}
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cmp = memcmp (seq, seq_data.data, seq_data.length);
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krb5_data_free (&seq_data);
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if (cmp != 0) {
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return GSS_S_BAD_MIC;
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}
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krb5_auth_setremoteseqnumber (gssapi_krb5_context,
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context_handle->auth_context,
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++seq_number);
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/* verify checksum */
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memcpy (cksum, p + 8, 20);
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memcpy (p + 20, p - 8, 8);
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csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
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csum.checksum.length = 20;
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csum.checksum.data = cksum;
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ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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ret = krb5_verify_checksum (gssapi_krb5_context, crypto,
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KRB5_KU_USAGE_SIGN,
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p + 20,
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input_message_buffer->length - len + 8,
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&csum);
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krb5_crypto_destroy (gssapi_krb5_context, crypto);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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/* copy out data */
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output_message_buffer->length = input_message_buffer->length
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- len - padlength - 8;
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output_message_buffer->value = malloc(output_message_buffer->length);
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if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
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return GSS_S_FAILURE;
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memcpy (output_message_buffer->value,
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p + 36,
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output_message_buffer->length);
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return GSS_S_COMPLETE;
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}
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OM_uint32 gss_unwrap
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(OM_uint32 * minor_status,
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const gss_ctx_id_t context_handle,
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const gss_buffer_t input_message_buffer,
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gss_buffer_t output_message_buffer,
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int * conf_state,
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gss_qop_t * qop_state
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)
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{
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krb5_keyblock *key;
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OM_uint32 ret;
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krb5_keytype keytype;
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ret = gss_krb5_getsomekey(context_handle, &key);
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if (ret) {
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*minor_status = ret;
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return GSS_S_FAILURE;
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}
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krb5_enctype_to_keytype (gssapi_krb5_context, key->keytype, &keytype);
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switch (keytype) {
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case KEYTYPE_DES :
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ret = unwrap_des (minor_status, context_handle,
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input_message_buffer, output_message_buffer,
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conf_state, qop_state, key);
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break;
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case KEYTYPE_DES3 :
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ret = unwrap_des3 (minor_status, context_handle,
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input_message_buffer, output_message_buffer,
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conf_state, qop_state, key);
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break;
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default :
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*minor_status = KRB5_PROG_ETYPE_NOSUPP;
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ret = GSS_S_FAILURE;
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break;
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}
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krb5_free_keyblock (gssapi_krb5_context, key);
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return ret;
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}
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