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/*
** Copyright 1998 - 1999 Double Precision, Inc. See COPYING for
** distribution information.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "authsasl.h"
#include "debug.h"
#if HAVE_HMACLIB
#include "../libhmac/hmac.h"
#include "cramlib.h"
static int nybble(int c)
{
if (c >= '0' && c <= '9') return (c-'0');
if (c >= 'a' && c <= 'f') return (c-'a'+10);
if (c >= 'A' && c <= 'F') return (c-'A'+10);
return (-1);
}
static int do_auth_verify_cram(struct hmac_hashinfo *hash,
const char *challenge, const char *response,
const char *hashsecret)
{
unsigned char *context;
unsigned i;
if (strlen(hashsecret) != hash->hh_L*4 ||
strlen(response) != hash->hh_L*2)
return (-1);
if ((context=malloc(hash->hh_L*3)) == 0) return (-1);
for (i=0; i<hash->hh_L*2; i++)
{
int a=nybble(hashsecret[i*2]), b=nybble(hashsecret[i*2+1]);
if (a < 0 || b < 0)
{
free(context);
return (-1);
}
context[i]= a*16 + b;
}
hmac_hashtext(hash, challenge, strlen(challenge),
context, context+hash->hh_L,
context+hash->hh_L*2);
for (i=0; i<hash->hh_L; i++)
{
int a=nybble(response[i*2]), b=nybble(response[i*2+1]);
if ( (unsigned char)(a*16+b) !=
context[hash->hh_L*2+i])
{
free(context);
return (-1);
}
}
free(context);
return (0);
}
int auth_verify_cram(struct hmac_hashinfo *hash,
const char *challenge, const char *response,
const char *hashsecret)
{
int rc;
rc = do_auth_verify_cram(hash, challenge, response, hashsecret);
dprintf(rc ? "cram validation failed" : "cram validation succeeded");
return rc;
}
int auth_get_cram(const char *authtype, char *authdata,
struct hmac_hashinfo **hmacptr,
char **user, char **challenge, char **response)
{
int i;
int challenge_l;
int response_l;
if (strncmp(authtype, "cram-", 5) ||
(*challenge=strtok(authdata, "\n")) == 0 ||
(*response=strtok(0, "\n")) == 0)
{
dprintf("cram: only supports authtype=cram-*");
errno=EPERM;
return (-1);
}
for (i=0; hmac_list[i]; i++)
if (strcmp(hmac_list[i]->hh_name, authtype+5) == 0)
break;
if (hmac_list[i] == 0
|| (challenge_l=authsasl_frombase64(*challenge)) < 0
|| (response_l=authsasl_frombase64(*response)) < 0)
{
dprintf("cram: unrecognised authtype or invalid base64 encoding");
errno=EACCES;
return (-1);
}
*hmacptr=hmac_list[i];
for (i=0; i<response_l; i++)
if ((*response)[i] == ' ')
break;
if (i >= response_l)
{
dprintf("cram: invalid base64 encoding");
errno=EACCES;
return (-1);
}
(*response)[i++]=0;
*user = *response;
(*response) += i;
response_l -= i;
/* Since base64decoded data is always lesser in size (at least),
** we can do the following:
*/
(*challenge)[challenge_l]=0;
(*response)[response_l]=0;
/* we rely on dprintf doing a "safe" print here */
dprintf("cram: decoded challenge/response, username '%s'", *user);
return (0);
}
#endif
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