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/*
* Copyright 1990,1991 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
* Sandia National Laboratories also makes no representations about the
* suitability of the modifications, or additions to this software for
* any purpose. It is provided "as is" without express or implied warranty.
*
* Note: The internal interfaces to this routine are subject to change
* and/or cleanup. You should only expect the interfaces to
* krb5_obtain_padata and krb5_verify_padata to have some chance of
* staying stable. [tytso:19920903.1544EDT]
*/
/*
* This file contains routines for establishing, verifying, and any other
* necessary functions, for utilizing the pre-authentication field of the
* kerberos kdc request, with various hardware/software verification devices.
*
* Note: At some point these functions may very well be split apart
* into different files.... [tytso:19920903.1618EDT]
*/
#include <stdio.h>
#include <time.h>
#include "k5-int.h"
#include <syslog.h>
static krb5_preauth_ops preauth_systems[] = {
{
0,
KRB5_PADATA_ENC_UNIX_TIME,
KRB5_PREAUTH_FLAGS_ENCRYPT,
get_unixtime_padata,
verify_unixtime_padata,
},
{
0,
KRB5_PADATA_ENC_SANDIA_SECURID,
KRB5_PREAUTH_FLAGS_ENCRYPT | KRB5_PREAUTH_FLAGS_HARDWARE,
get_securid_padata,
verify_securid_padata,
},
{ -1,}
};
static krb5_error_code find_preauthenticator
PROTOTYPE((int type, krb5_preauth_ops **Preauth_proc));
/*
* krb5_obtain_padata is a glue routine which when passed in
* a preauthentication type, client principal, and src_addr, returns
* preauthentication data contained in data to be passed onto the KDC.
*
* If problems occur then a non zero value is returned...
*
* Note: This is a first crack at what any preauthentication will need...
*/
krb5_error_code INTERFACE
krb5_obtain_padata(context, type, client, src_addr, encrypt_key, ret_data)
krb5_context context;
int type; /*IN: Preauth type */
krb5_principal client; /*IN: requestor */
krb5_address **src_addr; /*IN: array of ptrs to addresses */
krb5_keyblock *encrypt_key; /*IN: encryption key */
krb5_pa_data **ret_data; /*OUT: Returned padata */
{
krb5_error_code retval;
krb5_preauth_ops *p_system;
krb5_encrypt_block eblock;
krb5_data scratch;
krb5_pa_data *data;
if (!ret_data)
return EINVAL;
*ret_data = 0;
if (type == KRB5_PADATA_NONE )
return(0);
data = (krb5_pa_data *) malloc(sizeof(krb5_pa_data));
if (!data)
return ENOMEM;
data->length = 0;
data->contents = 0;
data->pa_type = type;
/* Find appropriate preauthenticator */
retval = find_preauthenticator(type, &p_system);
if (retval)
goto error_out;
retval = (*p_system->obtain)(context, client, src_addr, data );
if (retval)
goto error_out;
/* Check to see if we need to encrypt padata */
if (p_system->flags & KRB5_PREAUTH_FLAGS_ENCRYPT) {
/* If we dont have a encryption key we are out of luck */
if (!encrypt_key) {
retval = KRB5_PREAUTH_NO_KEY;
goto error_out;
}
krb5_use_keytype(context, &eblock, encrypt_key->keytype);
/* do any necessay key pre-processing */
retval = krb5_process_key(context, &eblock, encrypt_key);
if (retval)
goto error_out;
/*
* Set up scratch data and length for encryption
* Must allocate more space for checksum and confounder
* We also leave space for an uncrypted size field.
*/
scratch.length = krb5_encrypt_size(data->length,
eblock.crypto_entry) + 4;
if(!(scratch.data = malloc(scratch.length))){
(void) krb5_finish_key(context, &eblock);
retval = ENOMEM;
goto error_out;
}
scratch.data[0] = data->length >> 24;
scratch.data[1] = data->length >> 16;
scratch.data[2] = data->length >> 8;
scratch.data[3] = data->length;
/* Encrypt preauth data in encryption key */
if (retval = krb5_encrypt(context, (krb5_pointer) data->contents,
(char *) scratch.data + 4,
data->length, &eblock, 0)) {
(void) krb5_finish_key(context, &eblock);
free(scratch.data);
goto error_out;
}
(void) krb5_finish_key(context, &eblock);
free(data->contents);
data->length = scratch.length;
data->contents = (unsigned char *) scratch.data;
}
*ret_data = data;
return 0;
error_out:
free(data);
return retval;
}
/*
* krb5_verify_padata is a glue routine which when passed in
* the client, src_addr and padata verifies it with the appropriate
* verify function.
*
* If problems occur then a non zero value is returned...
* else returns zero if padata verifies, and returns a "unique" id.
*
* Note: This is a first crack at what any preauthentication will need...
*/
krb5_error_code INTERFACE
krb5_verify_padata(context, data,client,src_addr, decrypt_key, req_id, flags)
krb5_context context;
krb5_pa_data *data; /*IN: padata */
krb5_principal client; /*IN: requestor */
krb5_address **src_addr; /*IN: array of ptrs to addresses */
krb5_keyblock *decrypt_key; /*IN: decryption key */
int * req_id; /*OUT: identifier */
int * flags; /*OUT: flags */
{
krb5_preauth_ops *p_system;
krb5_encrypt_block eblock;
krb5_data scratch;
int free_scratch = 0;
krb5_checksum cksum;
krb5_error_code retval;
if (!data)
return(EINVAL);
/* Find appropriate preauthenticator */
retval = find_preauthenticator((int) data->pa_type, &p_system);
if (retval)
return retval;
/* Check to see if we need to decrypt padata */
if (p_system->flags & KRB5_PREAUTH_FLAGS_ENCRYPT) {
/* If we dont have a decryption key we are out of luck */
if (!decrypt_key)
return(EINVAL);
krb5_use_keytype(context, &eblock, decrypt_key->keytype);
scratch.length = data->length;
if (!(scratch.data = (char *)malloc(scratch.length))) {
return(ENOMEM);
}
/* do any necessay key pre-processing */
retval = krb5_process_key(context, &eblock,decrypt_key);
if (retval) {
free(scratch.data);
return(retval);
}
/* Decrypt data */
retval = krb5_decrypt(context, (char *) data->contents + 4,
(krb5_pointer) scratch.data,
scratch.length - 4, &eblock, 0);
if (retval) {
(void) krb5_finish_key(context, &eblock);
free(scratch.data);
return(retval);
}
scratch.length = (((int) ((unsigned char *)data->contents)[0] << 24)
+ ((int) ((unsigned char *)data->contents)[1] << 16)
+ ((int) ((unsigned char *)data->contents)[2] << 8)
+ (int) ((unsigned char *)data->contents)[3]);
free_scratch++;
} else {
scratch.data = (char *) data->contents;
scratch.length = data->length;
}
retval = (*p_system->verify)(context, client, src_addr, &scratch);
if (free_scratch)
free(scratch.data);
if (retval)
return retval;
if (flags)
*flags = p_system->flags;
/* Generate a request id by crc32ing the (encrypted) preauth data. */
/* Note: The idea behind req_id is that it is dependant upon
the information in data. This could then be used for
replay detection. */
/* MUST malloc cksum.contents */
cksum.contents = (krb5_octet *)calloc(1,
krb5_checksum_size(context, CKSUMTYPE_CRC32));
if (!cksum.contents) return(1);
if (krb5_calculate_checksum(context, CKSUMTYPE_CRC32,
data->contents,
data->length,
0, /* seed is ignored */
0, /* seed length is ignored */
&cksum )) {
*req_id = 0;
} else {
/* Checksum length should be 32 bits, so truncation should never
take place */
if ( cksum.length > sizeof(*req_id)) cksum.length = sizeof(*req_id);
/* Offset req_id for 64 bit systems */
memcpy((char *)req_id + (sizeof(*req_id) - cksum.length),
cksum.contents,cksum.length);
}
free(cksum.contents);
return(0);
}
static krb5_error_code
find_preauthenticator(type, preauth)
int type;
krb5_preauth_ops **preauth;
{
krb5_preauth_ops *ap = preauth_systems;
while ((ap->type != -1) && (ap->type != type))
ap++;
if (ap->type == -1)
return(KRB5_PREAUTH_BAD_TYPE);
*preauth = ap;
return 0;
}
/*
* Format is: 8 bytes of random confounder,
* 1 byte version number (currently 0),
* 4 bytes: number of seconds since Jan 1, 1970, in MSB order.
*/
int seeded = 0 ; /* Used by srand below */
krb5_error_code INTERFACE
get_unixtime_padata(context, client, src_addr, pa_data)
krb5_context context;
krb5_principal client;
krb5_address **src_addr;
krb5_pa_data *pa_data;
{
unsigned char *tmp;
krb5_error_code retval;
krb5_timestamp kdc_time;
int i;
pa_data->length = 13;
tmp = pa_data->contents = (unsigned char *) malloc(pa_data->length);
if (!tmp)
return(ENOMEM);
retval = krb5_timeofday(context, &kdc_time);
if (retval)
return retval;
if ( !seeded) {
seeded = kdc_time + getpid();
srand(seeded);
}
for (i=0; i < 8; i++)
*tmp++ = rand() & 255;
*tmp++ = 0;
*tmp++ = (kdc_time >> 24) & 255;
*tmp++ = (kdc_time >> 16) & 255;
*tmp++ = (kdc_time >> 8) & 255;
*tmp++ = kdc_time & 255;
return(0);
}
krb5_error_code INTERFACE
verify_unixtime_padata(context, client, src_addr, data)
krb5_context context;
krb5_principal client;
krb5_address **src_addr;
krb5_data *data;
{
unsigned char *tmp;
krb5_error_code retval;
krb5_timestamp currenttime, patime;
extern krb5_deltat krb5_clockskew;
#define in_clock_skew(date) (labs((date)-currenttime) < krb5_clockskew)
tmp = (unsigned char *) data->data;
if (tmp[8] != 0)
return KRB5_PREAUTH_FAILED;
patime = (int) tmp[9] << 24;
patime += (int) tmp[10] << 16;
patime += (int) tmp[11] << 8;
patime += tmp[12];
retval = krb5_timeofday(context, ¤ttime);
if (retval)
return retval;
if (!in_clock_skew(patime))
return KRB5_PREAUTH_FAILED;
return 0;
}
#ifdef KRBCONF_SECUREID
#include "sdcli.h"
#include "sdconf.c"
krb5_error_code INTERFACE
verify_securid_padata(client, src_addr, data)
krb5_principal client;
krb5_address **src_addr;
krb5_data *data;
{
extern perform_hw;
if (perform_hw) {
krb5_error_code retval;
char username[255];
struct SD_CLIENT sd;
memset((char *)&sd,0, sizeof (sd));
memset((char *) username, 0, sizeof(username));
memcpy((char *) username, krb5_princ_component(context, client,0)->data,
krb5_princ_component(context, client,0)->length);
/* If Instance then Append */
if (krb5_princ_size(context, client) > 1 ) {
if (strncmp(krb5_princ_realm(context, client)->data,
krb5_princ_component(context, client,1)->data,
krb5_princ_component(context, client,1)->length) ||
krb5_princ_realm(context, client)->length !=
krb5_princ_component(context, client,1)->length) {
strncat(username,"/",1);
strncat(username,krb5_princ_component(context, client,1)->data,
krb5_princ_component(context, client,1)->length);
}
}
if (retval = sd_check(data->data,username,&sd) != ACM_OK) {
syslog(LOG_INFO,
"%s - Invalid Securid Authentication Data sd_check Code %d",
username, retval);
return(KRB5_PREAUTH_FAILED);
}
return(0);
} else {
char *username = 0;
krb5_unparse_name(context, client,&username);
syslog(LOG_INFO,
"%s Provided Securid but this KDC does not support Securid",
username);
free(username);
return(KRB5_PREAUTH_FAILED);
}
}
#else
krb5_error_code INTERFACE
verify_securid_padata(context, client, src_addr, data)
krb5_context context;
krb5_principal client;
krb5_address **src_addr;
krb5_data *data;
{
char *username = 0;
krb5_unparse_name(context, client,&username);
syslog(LOG_INFO,
"%s Provided Securid but this KDC does not support Securid",
username);
free(username);
return(KRB5_PREAUTH_FAILED);
}
#endif
/*
static char *krb5_SecureId_prompt = "\nEnter Your SecurId Access Code Prepended with Your PIN\n (or a \'#\'if Your PIN is entered on the card keypad)\n or Type return <CR> if You Do NOT Use a SecurId Card: ";
*/
static char *krb5_SecureId_prompt = "\nEnter Your SecurId Access Code Prepended with Your PIN\n (or a \'#\'if Your PIN is entered on the card keypad): ";
krb5_error_code INTERFACE
get_securid_padata(context, client,src_addr,pa_data)
krb5_context context;
krb5_principal client;
krb5_address **src_addr;
krb5_pa_data *pa_data;
{
char temp[MAX_PREAUTH_SIZE];
int tempsize;
int retval = 0;
tempsize = sizeof(temp) - 1;
if (krb5_read_password(context, krb5_SecureId_prompt, 0, temp, &tempsize))
return(KRB5_PARSE_ILLCHAR);
temp[tempsize] = '\0';
if (temp[0] == '\0')
return(KRB5_PARSE_ILLCHAR);
pa_data->length = strlen(temp) + 1;
pa_data->contents = (krb5_octet *) calloc(1,pa_data->length);
if (pa_data->contents) {
memcpy(pa_data->contents,temp,pa_data->length);
retval = 0;
}
else retval = ENOMEM;
memset(temp,0,pa_data->length);
return(retval);
}
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