[xmlsec] How to change to "enveloping signature"

tommy tomizawa at gw3.csr.co.jp
Mon Nov 14 03:41:21 PST 2005


Dear Aleksey.

-- Fri, 11 Nov 2005 00:59:17 -0800 
-- Aleksey Sanin <aleksey at aleksey.com> wrote: 
> 
> 1) Add dsig:Object element to the template using
> xmlSecTmplSignatureAddObject() function (you'll
> need to generate and remember unique id, it will
> be used soon). Then put the content that you want to
> sign *under* this dsig:Object element
> 2) Change xmlSecTmplSignatureAddReference() call
> to set the URI to reference the dsig:Object element
> (e.g. if you dsig:Object element id is 'myid' then
> use URI '#myid').
> 3) Get rid of "xmlSecTmplReferenceAddTransform(..,
> xmlSecTransformEnvelopedId) call.
> 
> If I am not missing something, this should do it.

I tried it.
Please find attached sign3enveloping.c file.
When sign3eveloping.c was executed, 
"enveloping signature xml" was made.

Regards.

--tommy




-------------- next part --------------
/** 
 * XML Security Library example: Signing a file with a dynamicaly created template and an X509 certificate.
 * 
 * Signs a file using a dynamicaly created template, key from PEM file and
 * an X509 certificate. The signature has one reference with one enveloped 
 * transform to sign the whole document except the <dsig:Signature/> node 
 * itself. The key certificate is written in the <dsig:X509Data/> node.
 * 
 * This example was developed and tested with OpenSSL crypto library. The 
 * certificates management policies for another crypto library may break it.
 * 
 * Usage: 
 *	sign3 <xml-doc> <pem-key> 
 *
 * Example:
 *	./sign3 sign3-doc.xml rsakey.pem rsacert.pem > sign3-res.xml
 *
 * The result signature could be validated using verify3 example:
 *	./verify3 sign3-res.xml rootcert.pem
 *
 * This is free software; see Copyright file in the source
 * distribution for preciese wording.
 * 
 * Copyright (C) 2002-2003 Aleksey Sanin <aleksey at aleksey.com>
 */
// append by tommy
long _ftol( double ); //defined by VC6 C libs
long _ftol2( double dblSource ) { return _ftol( dblSource ); }

#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h>

#ifndef XMLSEC_NO_XSLT
#include <libxslt/xslt.h>
#endif /* XMLSEC_NO_XSLT */

#include <xmlsec/xmlsec.h>
#include <xmlsec/xmltree.h>
#include <xmlsec/xmldsig.h>
#include <xmlsec/templates.h>
#include <xmlsec/crypto.h>

int sign_file(const char* xml_file, const char* key_file, const char* cert_file);

int 
main(int argc, char **argv) {
    assert(argv);

    if(argc != 4) {
	fprintf(stderr, "Error: wrong number of arguments.\n");
	fprintf(stderr, "Usage: %s <xml-file> <key-file> <cert-file>\n", argv[0]);
	return(1);
    }

    /* Init libxml and libxslt libraries */
    xmlInitParser();
    LIBXML_TEST_VERSION
    xmlLoadExtDtdDefaultValue = XML_DETECT_IDS | XML_COMPLETE_ATTRS;
    xmlSubstituteEntitiesDefault(1);
#ifndef XMLSEC_NO_XSLT
    xmlIndentTreeOutput = 1; 
#endif /* XMLSEC_NO_XSLT */
        	
    /* Init xmlsec library */
    if(xmlSecInit() < 0) {
	fprintf(stderr, "Error: xmlsec initialization failed.\n");
	return(-1);
    }

    /* Check loaded library version */
    if(xmlSecCheckVersion() != 1) {
	fprintf(stderr, "Error: loaded xmlsec library version is not compatible.\n");
	return(-1);
    }

    /* Load default crypto engine if we are supporting dynamic
     * loading for xmlsec-crypto libraries. Use the crypto library
     * name ("openssl", "nss", etc.) to load corresponding 
     * xmlsec-crypto library.
     */
#ifdef XMLSEC_CRYPTO_DYNAMIC_LOADING
    if(xmlSecCryptoDLLoadLibrary(BAD_CAST XMLSEC_CRYPTO) < 0) {
	fprintf(stderr, "Error: unable to load default xmlsec-crypto library. Make sure\n"
			"that you have it installed and check shared libraries path\n"
			"(LD_LIBRARY_PATH) envornment variable.\n");
	return(-1);	
    }
#endif /* XMLSEC_CRYPTO_DYNAMIC_LOADING */

    /* Init crypto library */
    if(xmlSecCryptoAppInit(NULL) < 0) {
	fprintf(stderr, "Error: crypto initialization failed.\n");
	return(-1);
    }

    /* Init xmlsec-crypto library */
    if(xmlSecCryptoInit() < 0) {
	fprintf(stderr, "Error: xmlsec-crypto initialization failed.\n");
	return(-1);
    }

    if(sign_file(argv[1], argv[2], argv[3]) < 0) {
	return(-1);
    }    
    
    /* Shutdown xmlsec-crypto library */
    xmlSecCryptoShutdown();
    
    /* Shutdown crypto library */
    xmlSecCryptoAppShutdown();
    
    /* Shutdown xmlsec library */
    xmlSecShutdown();

    /* Shutdown libxslt/libxml */
#ifndef XMLSEC_NO_XSLT
    xsltCleanupGlobals();            
#endif /* XMLSEC_NO_XSLT */
    xmlCleanupParser();
    
    return(0);
}

/** 
 * sign_file:
 * @xml_file:		the XML file name.
 * @key_file:		the PEM private key file name.
 * @cert_file:		the x509 certificate PEM file.
 *
 * Signs the @xml_file using private key from @key_file and dynamicaly
 * created enveloped signature template. The certificate from @cert_file
 * is placed in the <dsig:X509Data/> node.
 *
 * Returns 0 on success or a negative value if an error occurs.
 */
int 
sign_file(const char* xml_file, const char* key_file, const char* cert_file) {
    xmlDocPtr doc = NULL;
    xmlNodePtr signNode = NULL;
    xmlNodePtr refNode = NULL;
    xmlNodePtr keyInfoNode = NULL;
    xmlSecDSigCtxPtr dsigCtx = NULL;
    xmlNodePtr objNode = NULL; // enveloping
    int res = -1;
    
    assert(xml_file);
    assert(key_file);
    assert(cert_file);

    /* load doc file */
    doc = xmlParseFile(xml_file);
    if ((doc == NULL) || (xmlDocGetRootElement(doc) == NULL)){
	fprintf(stderr, "Error: unable to parse file \"%s\"\n", xml_file);
	goto done;	
    }
    
    /* create signature template for RSA-SHA1 enveloped signature */
    signNode = xmlSecTmplSignatureCreate(doc, xmlSecTransformExclC14NId,
				         xmlSecTransformRsaSha1Id, NULL);
    if(signNode == NULL) {
	fprintf(stderr, "Error: failed to create signature template\n");
	goto done;		
    }


//// Enveloping !!!
    /* add <dsig:Signature/> node to the doc */
    objNode = xmlDocGetRootElement(doc) ;
    xmlDocSetRootElement(doc, signNode) ;
    refNode = xmlSecTmplSignatureAddReference(xmlDocGetRootElement(doc), 
                                              xmlSecTransformSha1Id,
                                              NULL, BAD_CAST "#Object1", NULL);
    if(refNode == NULL) {
        fprintf(stderr, "Error: failed to add reference to signature template\n");
        goto done;		
    }

    // Add ObjectNode
    refNode = xmlSecTmplSignatureAddObject( xmlDocGetRootElement(doc), 
                                            BAD_CAST "Object1", NULL,NULL ) ;
    if(refNode == NULL) {
        fprintf(stderr, "Error: failed to add reference to signature template\n");
        goto done;		
    }
    /* add enveloped transform */
    if(xmlSecTmplReferenceAddTransform(objNode, xmlSecTransformEnvelopedId) == NULL) {
	fprintf(stderr, "Error: failed to add enveloped transform to reference\n");
	goto done;		
    }
//// (END)Enveloping !!!


    
    /* add <dsig:KeyInfo/> and <dsig:X509Data/> */
    keyInfoNode = xmlSecTmplSignatureEnsureKeyInfo(signNode, NULL);
    if(keyInfoNode == NULL) {
	fprintf(stderr, "Error: failed to add key info\n");
	goto done;		
    }
    
    if(xmlSecTmplKeyInfoAddX509Data(keyInfoNode) == NULL) {
	fprintf(stderr, "Error: failed to add X509Data node\n");
	goto done;		
    }

    /* create signature context, we don't need keys manager in this example */
    dsigCtx = xmlSecDSigCtxCreate(NULL);
    if(dsigCtx == NULL) {
        fprintf(stderr,"Error: failed to create signature context\n");
	goto done;
    }

    /* load private key, assuming that there is not password */
    dsigCtx->signKey = xmlSecCryptoAppKeyLoad(key_file, xmlSecKeyDataFormatPem, NULL, NULL, NULL);
    if(dsigCtx->signKey == NULL) {
        fprintf(stderr,"Error: failed to load private pem key from \"%s\"\n", key_file);
	goto done;
    }
    
    /* load certificate and add to the key */
    if(xmlSecCryptoAppKeyCertLoad(dsigCtx->signKey, cert_file, xmlSecKeyDataFormatPem) < 0) {
        fprintf(stderr,"Error: failed to load pem certificate \"%s\"\n", cert_file);
	goto done;
    }

    /* set key name to the file name, this is just an example! */
    if(xmlSecKeySetName(dsigCtx->signKey, key_file) < 0) {
    	fprintf(stderr,"Error: failed to set key name for key from \"%s\"\n", key_file);
	goto done;
    }

    /* sign the template */
    if(xmlSecDSigCtxSign(dsigCtx, signNode) < 0) {
        fprintf(stderr,"Error: signature failed\n");
	goto done;
    }
        
    /* print signed document to stdout */
    xmlDocDump(stdout, doc);    /* success */
    res = 0;

done:    
    /* cleanup */
    if(dsigCtx != NULL) {
	xmlSecDSigCtxDestroy(dsigCtx);
    }
    
    if(doc != NULL) {
	xmlFreeDoc(doc); 
    }
    return(res);
}



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