/*
 * Copyright (c) 2006 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden). 
 * All rights reserved. 
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 *
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 *
 * 3. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE. 
 */

#include "hx_locl.h"
RCSID("$Id$");

struct revoke_crl {
    char *path;
    time_t last_modfied;
    CRLCertificateList crl;
    int verified;
};

struct revoke_ocsp {
    char *path;
    time_t last_modfied;
    OCSPBasicOCSPResponse ocsp;
    int verified;
};


struct hx509_revoke_ctx_data {
    struct {
	struct revoke_crl *val;
	size_t len;
    } crls;
    struct {
	struct revoke_ocsp *val;
	size_t len;
    } ocsps;
};

int
hx509_revoke_init(hx509_context context, hx509_revoke_ctx *revoke)
{
    *revoke = calloc(1, sizeof(**revoke));
    if (*revoke == NULL)
	return ENOMEM;

    (*revoke)->crls.len = 0;
    (*revoke)->crls.val = NULL;
    (*revoke)->ocsps.len = 0;
    (*revoke)->ocsps.val = NULL;

    return 0;
}

void
hx509_revoke_free(hx509_revoke_ctx *revoke)
{
    size_t i ;

    for (i = 0; i < (*revoke)->crls.len; i++) {
	free((*revoke)->crls.val[i].path);
	free_CRLCertificateList(&(*revoke)->crls.val[i].crl);
    }
    for (i = 0; i < (*revoke)->ocsps.len; i++) {
	free((*revoke)->ocsps.val[i].path);
	free_OCSPBasicOCSPResponse(&(*revoke)->ocsps.val[i].ocsp);
    }
    free((*revoke)->crls.val);

    memset(*revoke, 0, sizeof(**revoke));
    free(*revoke);
    *revoke = NULL;
}

static int
verify_ocsp(hx509_context context,
	    OCSPBasicOCSPResponse *ocsp,
	    time_t time_now,
	    hx509_certs certs)
{
    heim_octet_string os;
    hx509_cert signer = NULL;
    hx509_query q;
    int ret;
	
    _hx509_query_clear(&q);
	
    switch(ocsp->tbsResponseData.responderID.element) {
    case choice_OCSPResponderID_byName:
	q.match = HX509_QUERY_MATCH_SUBJECT_NAME;
	q.subject_name = &ocsp->tbsResponseData.responderID.u.byName;
	break;
    case choice_OCSPResponderID_byKey:
	ret = EINVAL;
	goto out;
    }
	
    os.data = ocsp->signature.data;
    os.length = ocsp->signature.length / 8;

    ret = hx509_certs_find(context, certs, &q, &signer);
    if (ret)
	goto out;

    ret = hx509_verify_signature(context,
				 signer, 
				 &ocsp->signatureAlgorithm,
				 &ocsp->tbsResponseData._save,
				 &os);
    if (ret)
	goto out;

    /* XXX verify signer is allowed to be OCSP signer */

out:
    if (signer)
	hx509_cert_free(signer);

    return ret;
}

/*
 *
 */

static int
load_ocsp(const char *path, time_t *t, OCSPBasicOCSPResponse *ocsp)
{
    size_t length, size;
    struct stat sb;
    void *data;
    int ret;

    memset(ocsp, 0, sizeof(*ocsp));

    ret = _hx509_map_file(path, &data, &length, &sb);
    if (ret)
	return ret;

    *t = sb.st_mtime;

    ret = decode_OCSPBasicOCSPResponse(data, length, ocsp, &size);
    _hx509_unmap_file(data, length);
    if (ret)
	return ret;

    /* check signature is aligned */
    if (ocsp->signature.length & 7) {
	free_OCSPBasicOCSPResponse(ocsp);
	return EINVAL;
    }
    return 0;
}

int
hx509_revoke_add_ocsp(hx509_context context,
		      hx509_revoke_ctx revoke,
		      const char *path)
{
    OCSPBasicOCSPResponse ocsp;
    void *data;
    int ret;
    size_t i;

    if (strncmp(path, "FILE:", 5) != 0)
	return EINVAL;

    path += 5;

    for (i = 0; i < revoke->ocsps.len; i++) {
	if (strcmp(revoke->ocsps.val[0].path, path) == 0)
	    return 0;
    }

    data = realloc(revoke->ocsps.val, 
		   (revoke->ocsps.len + 1) * sizeof(revoke->ocsps.val[0]));
    if (data == NULL)
	return ENOMEM;

    revoke->ocsps.val = data;

    memset(&revoke->ocsps.val[revoke->ocsps.len], 0, 
	   sizeof(revoke->ocsps.val[0]));

    revoke->ocsps.val[revoke->ocsps.len].path = strdup(path);
    if (revoke->ocsps.val[revoke->ocsps.len].path == NULL)
	return ENOMEM;

    ret = load_ocsp(path,
		   &revoke->ocsps.val[revoke->ocsps.len].last_modfied,
		   &revoke->ocsps.val[revoke->ocsps.len].ocsp);
    if (ret) {
	free(revoke->ocsps.val[revoke->ocsps.len].path);
	return ret;
    }

    revoke->ocsps.len++;


    if (ret)
	return ret;

    free_OCSPBasicOCSPResponse(&ocsp);

    return 0;
}

/*
 *
 */

static int
verify_crl(hx509_context context,
	   CRLCertificateList *crl,
	   time_t time_now,
	   hx509_certs certs)
{
    heim_octet_string os;
    hx509_cert signer;
    hx509_query q;
    time_t t;
    int ret;
	
    t = _hx509_Time2time_t(&crl->tbsCertList.thisUpdate);
    if (t > time_now)
	return HX509_CRL_USED_BEFORE_TIME;

    if (crl->tbsCertList.nextUpdate == NULL)
	return HX509_CRL_INVALID_FORMAT;

    t = _hx509_Time2time_t(crl->tbsCertList.nextUpdate);
    if (t < time_now)
	return HX509_CRL_USED_AFTER_TIME;

    _hx509_query_clear(&q);
	
    q.match = HX509_QUERY_MATCH_SUBJECT_NAME;
    q.subject_name = &crl->tbsCertList.issuer;
	
    ret = hx509_certs_find(context, certs, &q, &signer);
    if (ret)
	return ret;

    os.data = crl->signatureValue.data;
    os.length = crl->signatureValue.length / 8;

    ret = hx509_verify_signature(context,
				 signer, 
				 &crl->signatureAlgorithm,
				 &crl->tbsCertList._save,
				 &os);
    if (ret)
	goto out;

    /* XXX verify signer is allowed to be CRL signer */

out:
    hx509_cert_free(signer);

    return ret;
}

static int
load_crl(const char *path, time_t *t, CRLCertificateList *crl)
{
    size_t length, size;
    struct stat sb;
    void *data;
    int ret;

    memset(crl, 0, sizeof(*crl));

    ret = _hx509_map_file(path, &data, &length, &sb);
    if (ret)
	return ret;

    *t = sb.st_mtime;

    ret = decode_CRLCertificateList(data, length, crl, &size);
    _hx509_unmap_file(data, length);
    if (ret)
	return ret;

    /* check signature is aligned */
    if (crl->signatureValue.length & 7) {
	free_CRLCertificateList(crl);
	return EINVAL;
    }
    return 0;
}

int
hx509_revoke_add_crl(hx509_context context,
		     hx509_revoke_ctx revoke,
		     const char *path)
{
    void *data;
    size_t i;
    int ret;

    if (strncmp(path, "FILE:", 5) != 0)
	return EINVAL;
    
    path += 5;

    for (i = 0; i < revoke->crls.len; i++) {
	if (strcmp(revoke->crls.val[0].path, path) == 0)
	    return 0;
    }

    data = realloc(revoke->crls.val, 
		   (revoke->crls.len + 1) * sizeof(revoke->crls.val[0]));
    if (data == NULL)
	return ENOMEM;

    revoke->crls.val = data;

    memset(&revoke->crls.val[revoke->crls.len], 0, sizeof(revoke->crls.val[0]));

    revoke->crls.val[revoke->crls.len].path = strdup(path);
    if (revoke->crls.val[revoke->crls.len].path == NULL)
	return ENOMEM;

    ret = load_crl(path, 
		   &revoke->crls.val[revoke->crls.len].last_modfied,
		   &revoke->crls.val[revoke->crls.len].crl);
    if (ret) {
	free(revoke->crls.val[revoke->crls.len].path);
	return ret;
    }

    revoke->crls.len++;

    return ret;
}


int
hx509_revoke_verify(hx509_context context,
		    hx509_revoke_ctx revoke,
		    hx509_certs certs,
		    time_t now,
		    hx509_cert cert)
{
    const Certificate *c = _hx509_get_cert(cert);
    unsigned long i, j, k;
    int ret;

    for (i = 0; i < revoke->ocsps.len; i++) {
	struct revoke_ocsp *ocsp = &revoke->ocsps.val[i];
	struct stat sb;

	/* check this ocsp apply to this cert */

	/* check if there is a newer version of the file */
	ret = stat(ocsp->path, &sb);
	if (ret == 0 && ocsp->last_modfied != sb.st_mtime) {
	    OCSPBasicOCSPResponse o;

	    ret = load_ocsp(ocsp->path, &ocsp->last_modfied, &o);
	    if (ret == 0) {
		free_OCSPBasicOCSPResponse(&ocsp->ocsp);
		ocsp->ocsp = o;
		ocsp->verified = 0;
	    }
	}

	/* verify signature in ocsp if not already done */
	if (ocsp->verified == 0) {
	    ret = verify_ocsp(context, &ocsp->ocsp, now, certs);
	    if (ret)
		continue;
	    ocsp->verified = 1;
	}


	for (i = 0; i < ocsp->ocsp.tbsResponseData.responses.len; i++) {
	    heim_octet_string os;

	    ret = heim_integer_cmp(&ocsp->ocsp.tbsResponseData.responses.val[i].certID.serialNumber,
				   &c->tbsCertificate.serialNumber);
	    if (ret != 0)
		continue;
	    
	    /* verify issuer hashes hash */
	    ret = _hx509_verify_signature(NULL,
					  &ocsp->ocsp.tbsResponseData.responses.val[i].certID.hashAlgorithm,
					  &c->tbsCertificate.issuer._save,
					  &ocsp->ocsp.tbsResponseData.responses.val[i].certID.issuerNameHash);
	    if (ret != 0)
		continue;

	    os.data = c->tbsCertificate.subjectPublicKeyInfo.subjectPublicKey.data;
	    os.length = c->tbsCertificate.subjectPublicKeyInfo.subjectPublicKey.length / 8;

	    ret = _hx509_verify_signature(NULL,
					  &ocsp->ocsp.tbsResponseData.responses.val[i].certID.hashAlgorithm,
					  &os,
					  &ocsp->ocsp.tbsResponseData.responses.val[i].certID.issuerKeyHash);
	    if (ret != 0)
		continue;

	    switch (ocsp->ocsp.tbsResponseData.responses.val[i].certStatus.element) {
	    case choice_OCSPCertStatus_good:
		break;
	    case choice_OCSPCertStatus_revoked:
	    case choice_OCSPCertStatus_unknown:
		continue;
	    }

	    if (ocsp->ocsp.tbsResponseData.responses.val[i].thisUpdate < now)
		continue;

	    if (ocsp->ocsp.tbsResponseData.responses.val[i].nextUpdate) {
		if (*ocsp->ocsp.tbsResponseData.responses.val[i].nextUpdate < now)
		    continue;
	    } else
		/* Should force a refetch, but can we ? */;

	    return 0;
	}
    }

    for (i = 0; i < revoke->crls.len; i++) {
	struct revoke_crl *crl = &revoke->crls.val[i];
	struct stat sb;

	/* check if cert.issuer == crls.val[i].crl.issuer */
	ret = _hx509_name_cmp(&c->tbsCertificate.issuer, 
			      &crl->crl.tbsCertList.issuer);
	if (ret)
	    continue;

	ret = stat(crl->path, &sb);
	if (ret == 0 && crl->last_modfied != sb.st_mtime) {
	    CRLCertificateList c;

	    ret = load_crl(crl->path, &crl->last_modfied, &c);
	    if (ret == 0) {
		free_CRLCertificateList(&crl->crl);
		crl->crl = c;
		crl->verified = 0;
	    }
	}

	/* verify signature in crl if not already done */
	if (crl->verified == 0) {
	    ret = verify_crl(context, &crl->crl, now, certs);
	    if (ret)
		return ret;
	    crl->verified = 1;
	}
	
	if (crl->crl.tbsCertList.crlExtensions)
	    for (j = 0; j < crl->crl.tbsCertList.crlExtensions->len; j++)
		if (crl->crl.tbsCertList.crlExtensions->val[j].critical)
		    return HX509_CRL_UNKNOWN_EXTENSION;

	if (crl->crl.tbsCertList.revokedCertificates == NULL)
	    return 0;

	/* check if cert is in crl */
	for (j = 0; j < crl->crl.tbsCertList.revokedCertificates->len; j++) {
	    time_t t;

	    ret = heim_integer_cmp(&crl->crl.tbsCertList.revokedCertificates->val[j].userCertificate,
				   &c->tbsCertificate.serialNumber);
	    if (ret != 0)
		continue;

	    t = _hx509_Time2time_t(&crl->crl.tbsCertList.revokedCertificates->val[j].revocationDate);
	    if (t > now)
		continue;
	    
	    if (crl->crl.tbsCertList.revokedCertificates->val[j].crlEntryExtensions)
		for (k = 0; k < crl->crl.tbsCertList.revokedCertificates->val[j].crlEntryExtensions->len; k++)
		    if (crl->crl.tbsCertList.revokedCertificates->val[j].crlEntryExtensions->val[k].critical)
			return HX509_CRL_UNKNOWN_EXTENSION;
	    
	    return HX509_CRL_CERT_REVOKED;
	}
	return 0;
    }


    if (context->flags & HX509_CTX_VERIFY_MISSING_OK)
	return 0;
    return HX509_CRL_MISSING;
}