/*
 * Copyright 2001-2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <string.h>
#include "lber.h"
#include "ldap.h"
#include "ldap-int.h"
#include <sys/types.h>
#include <strings.h>
#include "sec.h"

/* text is the challenge, key is the password, digest is an allocated
   buffer (min 16 chars) which will contain the resulting digest */
void hmac_md5(unsigned char *text, int text_len, unsigned char *key,
        int key_len, unsigned char *digest)
{
        MD5_CTX context;
        unsigned char k_ipad[65];
        unsigned char k_opad[65];
        unsigned char tk[16];
        int i;

        if (key_len > 64){
                MD5_CTX tctx;

                (void) MD5Init(&tctx);
                (void) MD5Update(&tctx, key, key_len);
                (void) MD5Final(tk, &tctx);
                key = tk;
                key_len = 16;
        }

        bzero(k_ipad, sizeof (k_ipad));
        bzero(k_opad, sizeof (k_opad));
        bcopy(key, k_ipad, key_len);
        bcopy(key, k_opad, key_len);

        for (i=0; i<64; i++){
                k_ipad[i] ^= 0x36;
                k_opad[i] ^= 0x5c;
        }

        /* Perform inner MD5 */
        (void) MD5Init(&context);
        (void) MD5Update(&context, k_ipad, 64);
        (void) MD5Update(&context, text, text_len);
        (void) MD5Final(digest, &context);

        /* Perform outer MD5 */
        (void) MD5Init(&context);
        (void) MD5Update(&context, k_opad, 64);
        (void) MD5Update(&context, digest, 16);

        (void) MD5Final(digest, &context);

        return;
}

int ldap_sasl_cram_md5_bind_s(
        LDAP *ld,
        char *dn,
        struct berval *cred,
        LDAPControl **serverctrls,
        LDAPControl **clientctrls )
{
        int res;
        struct berval *challenge = NULL;
        struct berval resp;
        unsigned char digest[16];
        char *theHDigest;

        if (dn == NULL){
                return (LDAP_PARAM_ERROR);
        }

        bzero(digest, sizeof (digest));

        if ((res = ldap_sasl_bind_s(ld, NULL, LDAP_SASL_CRAM_MD5, NULL, serverctrls, clientctrls, &challenge))
                != LDAP_SASL_BIND_IN_PROGRESS){
                return (res);
        }
        if (challenge == NULL){
                return (LDAP_PARAM_ERROR);
        }

        LDAPDebug (LDAP_DEBUG_TRACE, "SASL challenge: %s\n", challenge->bv_val, 0, 0);

        hmac_md5((unsigned char *)challenge->bv_val, challenge->bv_len,
                                         (unsigned char *)cred->bv_val, cred->bv_len,  digest);
        ber_bvfree(challenge);
        challenge = NULL;

        theHDigest = hexa_print(digest, 16);
        if (theHDigest == NULL){
                return (LDAP_NO_MEMORY);
        }

        resp.bv_len = (strlen(dn) + 32 + 1);
        if ((resp.bv_val = (char *)malloc(resp.bv_len+1)) == NULL) {
                return(LDAP_NO_MEMORY);
        }

        sprintf(resp.bv_val, "%s %s", dn, theHDigest);
        free(theHDigest);

        LDAPDebug (LDAP_DEBUG_TRACE, "SASL response: %s\n", resp.bv_val, 0, 0);
        res = ldap_sasl_bind_s(ld, NULL, LDAP_SASL_CRAM_MD5, &resp, serverctrls, clientctrls, &challenge);

        free(resp.bv_val);
        return (res);
}