/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * Code for dealing with X509.V3 extensions.
 */

#include "cert.h"
#include "secitem.h"
#include "secoid.h"
#include "secder.h"
#include "secasn1.h"
#include "certxutl.h"
#include "secerr.h"

SECStatus
CERT_FindCertExtensionByOID(CERTCertificate *cert, SECItem *oid,
			    SECItem *value)
{
    return (cert_FindExtensionByOID (cert->extensions, oid, value));
}
    

SECStatus
CERT_FindCertExtension(const CERTCertificate *cert, int tag, SECItem *value)
{
    return (cert_FindExtension (cert->extensions, tag, value));
}

static void
SetExts(void *object, CERTCertExtension **exts)
{
    CERTCertificate *cert = (CERTCertificate *)object;

    cert->extensions = exts;
    DER_SetUInteger (cert->arena, &(cert->version), SEC_CERTIFICATE_VERSION_3);
}

void *
CERT_StartCertExtensions(CERTCertificate *cert)
{
    return (cert_StartExtensions ((void *)cert, cert->arena, SetExts));
}

/* find the given extension in the certificate of the Issuer of 'cert' */
SECStatus
CERT_FindIssuerCertExtension(CERTCertificate *cert, int tag, SECItem *value)
{
    CERTCertificate *issuercert;
    SECStatus rv;

    issuercert = CERT_FindCertByName(cert->dbhandle, &cert->derIssuer);
    if ( issuercert ) {
	rv = cert_FindExtension(issuercert->extensions, tag, value);
	CERT_DestroyCertificate(issuercert);
    } else {
	rv = SECFailure;
    }
    
    return(rv);
}

/* find a URL extension in the cert or its CA
 * apply the base URL string if it exists
 */
char *
CERT_FindCertURLExtension(CERTCertificate *cert, int tag, int catag)
{
    SECStatus rv;
    SECItem urlitem = {siBuffer,0};
    SECItem baseitem = {siBuffer,0};
    SECItem urlstringitem = {siBuffer,0};
    SECItem basestringitem = {siBuffer,0};
    PLArenaPool *arena = NULL;
    PRBool hasbase;
    char *urlstring;
    char *str;
    int len;
    unsigned int i;
    
    urlstring = NULL;

    arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
    if ( ! arena ) {
	goto loser;
    }
    
    hasbase = PR_FALSE;
    
    rv = cert_FindExtension(cert->extensions, tag, &urlitem);
    if ( rv == SECSuccess ) {
	rv = cert_FindExtension(cert->extensions, SEC_OID_NS_CERT_EXT_BASE_URL,
				   &baseitem);
	if ( rv == SECSuccess ) {
	    hasbase = PR_TRUE;
	}
	
    } else if ( catag ) {
	/* if the cert doesn't have the extensions, see if the issuer does */
	rv = CERT_FindIssuerCertExtension(cert, catag, &urlitem);
	if ( rv != SECSuccess ) {
	    goto loser;
	}	    
	rv = CERT_FindIssuerCertExtension(cert, SEC_OID_NS_CERT_EXT_BASE_URL,
					 &baseitem);
	if ( rv == SECSuccess ) {
	    hasbase = PR_TRUE;
	}
    } else {
	goto loser;
    }

    rv = SEC_QuickDERDecodeItem(arena, &urlstringitem,
                                SEC_ASN1_GET(SEC_IA5StringTemplate), &urlitem);

    if ( rv != SECSuccess ) {
	goto loser;
    }
    if ( hasbase ) {
	rv = SEC_QuickDERDecodeItem(arena, &basestringitem,
                                    SEC_ASN1_GET(SEC_IA5StringTemplate),
                                    &baseitem);

	if ( rv != SECSuccess ) {
	    goto loser;
	}
    }
    
    len = urlstringitem.len + ( hasbase ? basestringitem.len : 0 ) + 1;
    
    str = urlstring = (char *)PORT_Alloc(len);
    if ( urlstring == NULL ) {
	goto loser;
    }
    
    /* copy the URL base first */
    if ( hasbase ) {

	/* if the urlstring has a : in it, then we assume it is an absolute
	 * URL, and will not get the base string pre-pended
	 */
	for ( i = 0; i < urlstringitem.len; i++ ) {
	    if ( urlstringitem.data[i] == ':' ) {
		goto nobase;
	    }
	}
	
	PORT_Memcpy(str, basestringitem.data, basestringitem.len);
	str += basestringitem.len;
	
    }

nobase:
    /* copy the rest (or all) of the URL */
    PORT_Memcpy(str, urlstringitem.data, urlstringitem.len);
    str += urlstringitem.len;
    
    *str = '\0';
    goto done;
    
loser:
    if ( urlstring ) {
	PORT_Free(urlstring);
    }
    
    urlstring = NULL;
done:
    if ( arena ) {
	PORT_FreeArena(arena, PR_FALSE);
    }
    if ( baseitem.data ) {
	PORT_Free(baseitem.data);
    }
    if ( urlitem.data ) {
	PORT_Free(urlitem.data);
    }

    return(urlstring);
}

/*
 * get the value of the Netscape Certificate Type Extension
 */
SECStatus
CERT_FindNSCertTypeExtension(CERTCertificate *cert, SECItem *retItem)
{

    return (CERT_FindBitStringExtension
	    (cert->extensions, SEC_OID_NS_CERT_EXT_CERT_TYPE, retItem));    
}


/*
 * get the value of a string type extension
 */
char *
CERT_FindNSStringExtension(CERTCertificate *cert, int oidtag)
{
    SECItem wrapperItem, tmpItem = {siBuffer,0};
    SECStatus rv;
    PLArenaPool *arena = NULL;
    char *retstring = NULL;
    
    wrapperItem.data = NULL;
    tmpItem.data = NULL;
    
    arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
    
    if ( ! arena ) {
	goto loser;
    }
    
    rv = cert_FindExtension(cert->extensions, oidtag,
			       &wrapperItem);
    if ( rv != SECSuccess ) {
	goto loser;
    }

    rv = SEC_QuickDERDecodeItem(arena, &tmpItem,
                            SEC_ASN1_GET(SEC_IA5StringTemplate), &wrapperItem);

    if ( rv != SECSuccess ) {
	goto loser;
    }

    retstring = (char *)PORT_Alloc(tmpItem.len + 1 );
    if ( retstring == NULL ) {
	goto loser;
    }
    
    PORT_Memcpy(retstring, tmpItem.data, tmpItem.len);
    retstring[tmpItem.len] = '\0';

loser:
    if ( arena ) {
	PORT_FreeArena(arena, PR_FALSE);
    }
    
    if ( wrapperItem.data ) {
	PORT_Free(wrapperItem.data);
    }

    return(retstring);
}

/*
 * get the value of the X.509 v3 Key Usage Extension
 */
SECStatus
CERT_FindKeyUsageExtension(CERTCertificate *cert, SECItem *retItem)
{

    return (CERT_FindBitStringExtension(cert->extensions,
					SEC_OID_X509_KEY_USAGE, retItem));    
}

/*
 * get the value of the X.509 v3 Key Usage Extension
 */
SECStatus
CERT_FindSubjectKeyIDExtension(CERTCertificate *cert, SECItem *retItem)
{

    SECStatus rv;
    SECItem encodedValue = {siBuffer, NULL, 0 };
    SECItem decodedValue = {siBuffer, NULL, 0 };

    rv = cert_FindExtension
	 (cert->extensions, SEC_OID_X509_SUBJECT_KEY_ID, &encodedValue);
    if (rv == SECSuccess) {
	PLArenaPool * tmpArena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
	if (tmpArena) {
	    rv = SEC_QuickDERDecodeItem(tmpArena, &decodedValue, 
	                                SEC_ASN1_GET(SEC_OctetStringTemplate), 
					&encodedValue);
	    if (rv == SECSuccess) {
	        rv = SECITEM_CopyItem(NULL, retItem, &decodedValue);
	    }
	    PORT_FreeArena(tmpArena, PR_FALSE);
	} else {
	    rv = SECFailure;
	}
    }
    SECITEM_FreeItem(&encodedValue, PR_FALSE);
    return rv;
}

SECStatus
CERT_FindBasicConstraintExten(CERTCertificate *cert,
			      CERTBasicConstraints *value)
{
    SECItem encodedExtenValue;
    SECStatus rv;

    encodedExtenValue.data = NULL;
    encodedExtenValue.len = 0;

    rv = cert_FindExtension(cert->extensions, SEC_OID_X509_BASIC_CONSTRAINTS,
			    &encodedExtenValue);
    if ( rv != SECSuccess ) {
	return (rv);
    }

    rv = CERT_DecodeBasicConstraintValue (value, &encodedExtenValue);
    
    /* free the raw extension data */
    PORT_Free(encodedExtenValue.data);
    encodedExtenValue.data = NULL;
    
    return(rv);
}

CERTAuthKeyID *
CERT_FindAuthKeyIDExten (PLArenaPool *arena, CERTCertificate *cert)
{
    SECItem encodedExtenValue;
    SECStatus rv;
    CERTAuthKeyID *ret;
    
    encodedExtenValue.data = NULL;
    encodedExtenValue.len = 0;

    rv = cert_FindExtension(cert->extensions, SEC_OID_X509_AUTH_KEY_ID,
			    &encodedExtenValue);
    if ( rv != SECSuccess ) {
	return (NULL);
    }

    ret = CERT_DecodeAuthKeyID (arena, &encodedExtenValue);

    PORT_Free(encodedExtenValue.data);
    encodedExtenValue.data = NULL;
    
    return(ret);
}

SECStatus
CERT_CheckCertUsage(CERTCertificate *cert, unsigned char usage)
{
    SECItem keyUsage;
    SECStatus rv;

    /* There is no extension, v1 or v2 certificate */
    if (cert->extensions == NULL) {
	return (SECSuccess);
    }
    
    keyUsage.data = NULL;

    /* This code formerly ignored the Key Usage extension if it was
    ** marked non-critical.  That was wrong.  Since we do understand it,
    ** we are obligated to honor it, whether or not it is critical.
    */
    rv = CERT_FindKeyUsageExtension(cert, &keyUsage);
    if (rv == SECFailure) {
        rv = (PORT_GetError () == SEC_ERROR_EXTENSION_NOT_FOUND) ?
	    SECSuccess : SECFailure;
    } else if (!(keyUsage.data[0] & usage)) {
	PORT_SetError (SEC_ERROR_CERT_USAGES_INVALID);
	rv = SECFailure;
    }
    PORT_Free (keyUsage.data);
    return (rv);
}