450 lines
12 KiB
C
450 lines
12 KiB
C
/*
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* Copyright (c) 1997 - 2004 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 "gsskrb5_locl.h"
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#ifdef HEIM_WEAK_CRYPTO
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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 gsskrb5_ctx 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, *seq;
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size_t len;
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EVP_MD_CTX *md5;
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u_char hash[16];
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EVP_CIPHER_CTX des_ctx;
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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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size_t i;
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uint32_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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int cmp;
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int token_len;
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if (IS_DCE_STYLE(context_handle)) {
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token_len = 22 + 8 + 15; /* 45 */
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} else {
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token_len = input_message_buffer->length;
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}
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p = input_message_buffer->value;
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ret = _gsskrb5_verify_header (&p,
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token_len,
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"\x02\x01",
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GSS_KRB5_MECHANISM);
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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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memset (&zero, 0, sizeof(zero));
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for (i = 0; i < sizeof(deskey); ++i)
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deskey[i] ^= 0xf0;
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EVP_CIPHER_CTX_init(&des_ctx);
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EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, deskey, zero, 0);
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EVP_Cipher(&des_ctx, p, p, input_message_buffer->length - len);
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EVP_CIPHER_CTX_cleanup(&des_ctx);
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memset (&schedule, 0, sizeof(schedule));
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}
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if (IS_DCE_STYLE(context_handle)) {
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padlength = 0;
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} else {
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/* check pad */
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ret = _gssapi_verify_pad(input_message_buffer,
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input_message_buffer->length - len,
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&padlength);
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if (ret)
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return ret;
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}
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md5 = EVP_MD_CTX_create();
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EVP_DigestInit_ex(md5, EVP_md5(), NULL);
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EVP_DigestUpdate(md5, p - 24, 8);
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EVP_DigestUpdate(md5, p, input_message_buffer->length - len);
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EVP_DigestFinal_ex(md5, hash, NULL);
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EVP_MD_CTX_destroy(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_unchecked (&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 (ct_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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HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
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p -= 16;
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EVP_CIPHER_CTX_init(&des_ctx);
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EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0);
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EVP_Cipher(&des_ctx, p, p, 8);
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EVP_CIPHER_CTX_cleanup(&des_ctx);
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memset (deskey, 0, sizeof(deskey));
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memset (&schedule, 0, sizeof(schedule));
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seq = p;
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_gsskrb5_decode_om_uint32(seq, &seq_number);
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if (context_handle->more_flags & LOCAL)
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cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
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else
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cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
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if (cmp != 0) {
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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return GSS_S_BAD_MIC;
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}
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ret = _gssapi_msg_order_check(context_handle->order, seq_number);
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if (ret) {
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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return ret;
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}
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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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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#endif
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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 gsskrb5_ctx context_handle,
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krb5_context context,
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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;
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size_t len;
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u_char *seq;
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krb5_data seq_data;
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u_char cksum[20];
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uint32_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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int token_len;
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if (IS_DCE_STYLE(context_handle)) {
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token_len = 34 + 8 + 15; /* 57 */
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} else {
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token_len = input_message_buffer->length;
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}
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p = input_message_buffer->value;
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ret = _gsskrb5_verify_header (&p,
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token_len,
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"\x02\x01",
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GSS_KRB5_MECHANISM);
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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 (ct_memcmp (p, "\x02\x00", 2) == 0) {
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cstate = 1;
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} else if (ct_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 (ct_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(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(context, crypto, KRB5_KU_USAGE_SEAL,
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p, input_message_buffer->length - len, &tmp);
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krb5_crypto_destroy(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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if (IS_DCE_STYLE(context_handle)) {
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padlength = 0;
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} else {
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/* check pad */
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ret = _gssapi_verify_pad(input_message_buffer,
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input_message_buffer->length - len,
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&padlength);
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if (ret)
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return ret;
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}
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/* verify sequence number */
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HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
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p -= 28;
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ret = krb5_crypto_init(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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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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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 (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 (context, crypto);
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if (ret) {
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*minor_status = ret;
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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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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*minor_status = 0;
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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return GSS_S_BAD_MIC;
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}
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seq = seq_data.data;
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_gsskrb5_decode_om_uint32(seq, &seq_number);
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if (context_handle->more_flags & LOCAL)
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cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
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else
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cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
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krb5_data_free (&seq_data);
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if (cmp != 0) {
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*minor_status = 0;
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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return GSS_S_BAD_MIC;
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}
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ret = _gssapi_msg_order_check(context_handle->order, seq_number);
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if (ret) {
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*minor_status = 0;
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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return ret;
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}
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HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
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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(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 (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 (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 GSSAPI_CALLCONV _gsskrb5_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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krb5_context context;
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OM_uint32 ret;
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gsskrb5_ctx ctx = (gsskrb5_ctx) context_handle;
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output_message_buffer->value = NULL;
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output_message_buffer->length = 0;
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if (qop_state != NULL)
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*qop_state = GSS_C_QOP_DEFAULT;
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GSSAPI_KRB5_INIT (&context);
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if (ctx->more_flags & IS_CFX)
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return _gssapi_unwrap_cfx (minor_status, ctx, context,
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input_message_buffer, output_message_buffer,
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conf_state, qop_state);
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HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
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ret = _gsskrb5i_get_token_key(ctx, context, &key);
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HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
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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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*minor_status = 0;
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switch (key->keytype) {
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case KRB5_ENCTYPE_DES_CBC_CRC :
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case KRB5_ENCTYPE_DES_CBC_MD4 :
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case KRB5_ENCTYPE_DES_CBC_MD5 :
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#ifdef HEIM_WEAK_CRYPTO
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ret = unwrap_des (minor_status, ctx,
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input_message_buffer, output_message_buffer,
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conf_state, qop_state, key);
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#else
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ret = GSS_S_FAILURE;
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#endif
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break;
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case KRB5_ENCTYPE_DES3_CBC_MD5 :
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case KRB5_ENCTYPE_DES3_CBC_SHA1 :
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ret = unwrap_des3 (minor_status, ctx, context,
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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 KRB5_ENCTYPE_ARCFOUR_HMAC_MD5:
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case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5_56:
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ret = _gssapi_unwrap_arcfour (minor_status, ctx, context,
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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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abort();
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break;
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}
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krb5_free_keyblock (context, key);
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return ret;
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}
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