420b334bba
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@1935 ec53bebd-3082-4978-b11e-865c3cabbd6b
133 lines
3.4 KiB
C
133 lines
3.4 KiB
C
#include "gssapi_locl.h"
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RCSID("$Id$");
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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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u_char *p, *pad;
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size_t len;
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struct md5 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 key;
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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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p = input_message_buffer->value;
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len = GSS_KRB5_MECHANISM->length + 28;
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if (
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input_message_buffer->length < len
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|| memcmp (p, "\x60\x07\x06\x05", 4) != 0
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|| memcmp (p + 4, GSS_KRB5_MECHANISM->elements,
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GSS_KRB5_MECHANISM->length) != 0)
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return GSS_S_BAD_MECH;
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if (memcmp (p + 4 + GSS_KRB5_MECHANISM->length, "\x02\x01", 2) != 0)
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return GSS_S_DEFECTIVE_TOKEN;
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p += 6 + GSS_KRB5_MECHANISM->length;
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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, "\x0\x00", 2) != 0)
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return GSS_S_BAD_MIC;
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p += 2;
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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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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_finito (&md5, hash);
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memset (&zero, 0, sizeof(zero));
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memcpy (&key, context_handle->auth_context->key.keyvalue.data,
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sizeof(key));
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des_set_key (&key, schedule);
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des_cbc_cksum ((des_cblock *)hash,
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(des_cblock *)hash, sizeof(hash), 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) ? 0 : 0xFF,
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4);
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p -= 16;
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des_set_key (&key, schedule);
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des_cbc_encrypt ((des_cblock *)p, (des_cblock *)p, 8,
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schedule, (des_cblock *)hash, DES_DECRYPT);
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memset (key, 0, sizeof(key));
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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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/* decrypt data */
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p += 16;
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memset (&zero, 0, sizeof(zero));
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memcpy (&key, context_handle->auth_context->key.keyvalue.data,
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sizeof(key));
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for (i = 0; i < sizeof(key); ++i)
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key[i] ^= 0xf0;
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des_set_key (&key, schedule);
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des_cbc_encrypt ((des_cblock *)p,
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(des_cblock *)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 (key, 0, sizeof(key));
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memset (schedule, 0, sizeof(schedule));
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/* check pad */
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pad = (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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/* copy out data */
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output_message_buffer->length = input_message_buffer->length
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- len - 8 - padlength;
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output_message_buffer->value = malloc(output_message_buffer->length);
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if(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 + 8,
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output_message_buffer->length);
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return GSS_S_COMPLETE;
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}
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