diff options
Diffstat (limited to 'crypto/heimdal/lib/gssapi/unwrap.c')
| -rw-r--r-- | crypto/heimdal/lib/gssapi/unwrap.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/crypto/heimdal/lib/gssapi/unwrap.c b/crypto/heimdal/lib/gssapi/unwrap.c new file mode 100644 index 0000000..45b1df1 --- /dev/null +++ b/crypto/heimdal/lib/gssapi/unwrap.c @@ -0,0 +1,190 @@ +/* + * Copyright (c) 1997, 1998 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 "gssapi_locl.h" + +RCSID("$Id: unwrap.c,v 1.10 1999/12/02 17:05:04 joda Exp $"); + +OM_uint32 +gss_krb5_getsomekey(const gss_ctx_id_t context_handle, + des_cblock *key) +{ + /* XXX this is ugly, and probably incorrect... */ + krb5_keyblock *skey; + krb5_auth_con_getlocalsubkey(gssapi_krb5_context, + context_handle->auth_context, + &skey); + if(skey == NULL) + krb5_auth_con_getremotesubkey(gssapi_krb5_context, + context_handle->auth_context, + &skey); + if(skey == NULL) + krb5_auth_con_getkey(gssapi_krb5_context, + context_handle->auth_context, + &skey); + if(skey == NULL) + return GSS_S_FAILURE; + memcpy(key, skey->keyvalue.data, sizeof(*key)); + krb5_free_keyblock(gssapi_krb5_context, skey); + return 0; +} + +OM_uint32 gss_unwrap + (OM_uint32 * minor_status, + const gss_ctx_id_t context_handle, + const gss_buffer_t input_message_buffer, + gss_buffer_t output_message_buffer, + int * conf_state, + gss_qop_t * qop_state + ) +{ + u_char *p, *pad; + size_t len; + struct md5 md5; + u_char hash[16], seq_data[8]; + des_key_schedule schedule; + des_cblock key; + des_cblock zero; + int i; + int32_t seq_number; + size_t padlength; + OM_uint32 ret; + int cstate; + + p = input_message_buffer->value; + ret = gssapi_krb5_verify_header (&p, + input_message_buffer->length, + "\x02\x01"); + if (ret) + return ret; + + if (memcmp (p, "\x00\x00", 2) != 0) + return GSS_S_BAD_SIG; + p += 2; + if (memcmp (p, "\x00\x00", 2) == 0) { + cstate = 1; + } else if (memcmp (p, "\xFF\xFF", 2) == 0) { + cstate = 0; + } else + return GSS_S_BAD_MIC; + p += 2; + if(conf_state != NULL) + *conf_state = cstate; + if (memcmp (p, "\xff\xff", 2) != 0) + return GSS_S_DEFECTIVE_TOKEN; + p += 2; + p += 16; + + len = p - (u_char *)input_message_buffer->value; + + if(cstate) { + /* decrypt data */ + gss_krb5_getsomekey(context_handle, &key); + for (i = 0; i < sizeof(key); ++i) + key[i] ^= 0xf0; + des_set_key (&key, schedule); + memset (&zero, 0, sizeof(zero)); + des_cbc_encrypt ((des_cblock *)p, + (des_cblock *)p, + input_message_buffer->length - len, + schedule, + &zero, + DES_DECRYPT); + + memset (key, 0, sizeof(key)); + memset (schedule, 0, sizeof(schedule)); + } + /* check pad */ + + pad = (u_char *)input_message_buffer->value + input_message_buffer->length - 1; + padlength = *pad; + + for (i = padlength; i > 0 && *pad == padlength; i--, pad--) + ; + if (i != 0) + return GSS_S_BAD_MIC; + + md5_init (&md5); + md5_update (&md5, p - 24, 8); + md5_update (&md5, p, input_message_buffer->length - len); + md5_finito (&md5, hash); + + memset (&zero, 0, sizeof(zero)); + gss_krb5_getsomekey(context_handle, &key); + des_set_key (&key, schedule); + des_cbc_cksum ((des_cblock *)hash, + (des_cblock *)hash, sizeof(hash), schedule, &zero); + if (memcmp (p - 8, hash, 8) != 0) + return GSS_S_BAD_MIC; + + /* verify sequence number */ + + krb5_auth_getremoteseqnumber (gssapi_krb5_context, + context_handle->auth_context, + &seq_number); + seq_data[0] = (seq_number >> 0) & 0xFF; + seq_data[1] = (seq_number >> 8) & 0xFF; + seq_data[2] = (seq_number >> 16) & 0xFF; + seq_data[3] = (seq_number >> 24) & 0xFF; + memset (seq_data + 4, + (context_handle->more_flags & LOCAL) ? 0xFF : 0, + 4); + + p -= 16; + des_set_key (&key, schedule); + des_cbc_encrypt ((des_cblock *)p, (des_cblock *)p, 8, + schedule, (des_cblock *)hash, DES_DECRYPT); + + memset (key, 0, sizeof(key)); + memset (schedule, 0, sizeof(schedule)); + + if (memcmp (p, seq_data, 8) != 0) { + return GSS_S_BAD_MIC; + } + + krb5_auth_setremoteseqnumber (gssapi_krb5_context, + context_handle->auth_context, + ++seq_number); + + /* copy out data */ + + output_message_buffer->length = input_message_buffer->length + - len - 8 - padlength; + output_message_buffer->value = malloc(output_message_buffer->length); + if(output_message_buffer->length != 0 && output_message_buffer->value == NULL) + return GSS_S_FAILURE; + memcpy (output_message_buffer->value, + p + 24, + output_message_buffer->length); + return GSS_S_COMPLETE; +} |
