Files
heimdal/lib/gssapi/verify_mic.c
Assar Westerlund 420b334bba adapt to krb5 changes
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@1935 ec53bebd-3082-4978-b11e-865c3cabbd6b
1997-06-29 08:40:23 +00:00

92 lines
2.4 KiB
C

#include "gssapi_locl.h"
RCSID("$Id$");
OM_uint32 gss_verify_mic
(OM_uint32 * minor_status,
const gss_ctx_id_t context_handle,
const gss_buffer_t message_buffer,
const gss_buffer_t token_buffer,
gss_qop_t * qop_state
)
{
u_char *p;
size_t len;
struct md5 md5;
u_char hash[16], seq_data[8];
des_key_schedule schedule;
des_cblock key;
des_cblock zero;
int32_t seq_number;
p = token_buffer->value;
len = GSS_KRB5_MECHANISM->length + 28;
if (
token_buffer->length < len
|| memcmp (p, "\x60\x07\x06\x05", 4) != 0
|| memcmp (p + 4, GSS_KRB5_MECHANISM->elements,
GSS_KRB5_MECHANISM->length) != 0)
return GSS_S_BAD_MECH;
if (memcmp (p + 4 + GSS_KRB5_MECHANISM->length, "\x01\x01", 2) != 0)
return GSS_S_DEFECTIVE_TOKEN;
p += 6 + GSS_KRB5_MECHANISM->length;
if (memcmp (p, "\x00\x00", 2) != 0)
return GSS_S_BAD_SIG;
p += 2;
if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
return GSS_S_BAD_MIC;
p += 4;
p += 16;
/* verify checksum */
md5_init (&md5);
md5_update (&md5, p - 24, 8);
md5_update (&md5, message_buffer->value,
message_buffer->length);
md5_finito (&md5, hash);
memset (&zero, 0, sizeof(zero));
memcpy (&key, context_handle->auth_context->key.keyvalue.data,
sizeof(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) {
memset (key, 0, sizeof(key));
memset (schedule, 0, sizeof(schedule));
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) ? 0 : 0xFF,
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);
return GSS_S_COMPLETE;
}