/**
* XML Security Library example: Encrypting XML file with a session key and dynamicaly created template.
*
* Encrypts XML file using a dynamicaly created template file and a session
* DES key (encrypted with an RSA key).
*
* Usage:
* ./encrypt3 <xml-doc> <rsa-pem-key-file>
*
* Example:
* ./encrypt3 encrypt3-doc.xml rsakey.pem > encrypt3-res.xml
*
* The result could be decrypted with decrypt3 example:
* ./decrypt3 encrypt3-res.xml
*
* This is free software; see Copyright file in the source
* distribution for preciese wording.
*
* Copyright (C) 2002-2024 Aleksey Sanin <aleksey@aleksey.com>. All Rights Reserved.
*/
#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>
#include <libxslt/security.h>
#endif /* XMLSEC_NO_XSLT */
#include <xmlsec/xmlsec.h>
#include <xmlsec/xmltree.h>
#include <xmlsec/xmlenc.h>
#include <xmlsec/templates.h>
#include <xmlsec/crypto.h>
xmlSecKeysMngrPtr load_rsa_keys(char* key_file);
int encrypt_file(xmlSecKeysMngrPtr mngr, const char* xml_file, const char* key_name);
int
main(int argc, char **argv) {
xmlSecKeysMngrPtr mngr;
#ifndef XMLSEC_NO_XSLT
xsltSecurityPrefsPtr xsltSecPrefs = NULL;
#endif /* XMLSEC_NO_XSLT */
assert(argv);
if(argc != 3) {
fprintf(stderr, "Error: wrong number of arguments.\n");
fprintf(stderr, "Usage: %s <xml-file> <key-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 libxslt */
#ifndef XMLSEC_NO_XSLT
/* disable everything */
xsltSecPrefs = xsltNewSecurityPrefs();
xsltSetSecurityPrefs(xsltSecPrefs, XSLT_SECPREF_READ_FILE, xsltSecurityForbid);
xsltSetSecurityPrefs(xsltSecPrefs, XSLT_SECPREF_WRITE_FILE, xsltSecurityForbid);
xsltSetSecurityPrefs(xsltSecPrefs, XSLT_SECPREF_CREATE_DIRECTORY, xsltSecurityForbid);
xsltSetSecurityPrefs(xsltSecPrefs, XSLT_SECPREF_READ_NETWORK, xsltSecurityForbid);
xsltSetSecurityPrefs(xsltSecPrefs, XSLT_SECPREF_WRITE_NETWORK, xsltSecurityForbid);
xsltSetDefaultSecurityPrefs(xsltSecPrefs);
#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(NULL) < 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 and/or LTDL_LIBRARY_PATH) environment variables.\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);
}
/* create keys manager and load keys */
mngr = load_rsa_keys(argv[2]);
if(mngr == NULL) {
return(-1);
}
/* we use key filename as key name here */
if(encrypt_file(mngr, argv[1], argv[2]) < 0) {
xmlSecKeysMngrDestroy(mngr);
return(-1);
}
/* destroy keys manager */
xmlSecKeysMngrDestroy(mngr);
/* Shutdown xmlsec-crypto library */
xmlSecCryptoShutdown();
/* Shutdown crypto library */
xmlSecCryptoAppShutdown();
/* Shutdown xmlsec library */
xmlSecShutdown();
/* Shutdown libxslt/libxml */
#ifndef XMLSEC_NO_XSLT
xsltFreeSecurityPrefs(xsltSecPrefs);
xsltCleanupGlobals();
#endif /* XMLSEC_NO_XSLT */
xmlCleanupParser();
return(0);
}
/**
* load_rsa_keys:
* @key_file: the key filename.
*
* Creates simple keys manager and load RSA key from #key_file in it.
* The caller is responsible for destroying returned keys manager using
* @xmlSecKeysMngrDestroy.
*
* Returns the pointer to newly created keys manager or NULL if an error
* occurs.
*/
xmlSecKeysMngrPtr
load_rsa_keys(char* key_file) {
xmlSecKeysMngrPtr mngr;
xmlSecKeyPtr key;
assert(key_file);
/* create and initialize keys manager, we use a simple list based
* keys manager, implement your own xmlSecKeysStore klass if you need
* something more sophisticated
*/
mngr = xmlSecKeysMngrCreate();
if(mngr == NULL) {
fprintf(stderr, "Error: failed to create keys manager.\n");
return(NULL);
}
if(xmlSecCryptoAppDefaultKeysMngrInit(mngr) < 0) {
fprintf(stderr, "Error: failed to initialize keys manager.\n");
xmlSecKeysMngrDestroy(mngr);
return(NULL);
}
/* load private RSA key */
key = xmlSecCryptoAppKeyLoadEx(key_file, xmlSecKeyDataTypePublic | xmlSecKeyDataTypePrivate, xmlSecKeyDataFormatPem, NULL, NULL, NULL);
if(key == NULL) {
fprintf(stderr,"Error: failed to load rsa key from file \"%s\"\n", key_file);
xmlSecKeysMngrDestroy(mngr);
return(NULL);
}
/* set key name to the file name, this is just an example! */
if(xmlSecKeySetName(key, BAD_CAST key_file) < 0) {
fprintf(stderr,"Error: failed to set key name for key from \"%s\"\n", key_file);
xmlSecKeyDestroy(key);
xmlSecKeysMngrDestroy(mngr);
return(NULL);
}
/* add key to keys manager, from now on keys manager is responsible
* for destroying key
*/
if(xmlSecCryptoAppDefaultKeysMngrAdoptKey(mngr, key) < 0) {
fprintf(stderr,"Error: failed to add key from \"%s\" to keys manager\n", key_file);
xmlSecKeyDestroy(key);
xmlSecKeysMngrDestroy(mngr);
return(NULL);
}
return(mngr);
}
/**
* encrypt_file:
* @mngr: the pointer to keys manager.
* @xml_file: the encryption template file name.
* @key_name: the RSA key name.
*
* Encrypts #xml_file using a dynamicaly created template, a session DES key
* and an RSA key from keys manager.
*
* Returns 0 on success or a negative value if an error occurs.
*/
int
encrypt_file(xmlSecKeysMngrPtr mngr, const char* xml_file, const char* key_name) {
xmlDocPtr doc = NULL;
xmlNodePtr encDataNode = NULL;
xmlNodePtr keyInfoNode = NULL;
xmlNodePtr encKeyNode = NULL;
xmlNodePtr keyInfoNode2 = NULL;
xmlSecEncCtxPtr encCtx = NULL;
int res = -1;
assert(mngr);
assert(xml_file);
assert(key_name);
/* load template */
doc = xmlReadFile(xml_file, NULL, XML_PARSE_PEDANTIC | XML_PARSE_NONET);
if ((doc == NULL) || (xmlDocGetRootElement(doc) == NULL)){
fprintf(stderr, "Error: unable to parse file \"%s\"\n", xml_file);
goto done;
}
/* create encryption template to encrypt XML file and replace
* its content with encryption result */
encDataNode = xmlSecTmplEncDataCreate(doc, xmlSecTransformDes3CbcId,
NULL, xmlSecTypeEncElement, NULL, NULL);
if(encDataNode == NULL) {
fprintf(stderr, "Error: failed to create encryption template\n");
goto done;
}
/* we want to put encrypted data in the <enc:CipherValue/> node */
if(xmlSecTmplEncDataEnsureCipherValue(encDataNode) == NULL) {
fprintf(stderr, "Error: failed to add CipherValue node\n");
goto done;
}
/* add <dsig:KeyInfo/> */
keyInfoNode = xmlSecTmplEncDataEnsureKeyInfo(encDataNode, NULL);
if(keyInfoNode == NULL) {
fprintf(stderr, "Error: failed to add key info\n");
goto done;
}
/* add <enc:EncryptedKey/> to store the encrypted session key */
encKeyNode = xmlSecTmplKeyInfoAddEncryptedKey(keyInfoNode,
xmlSecTransformRsaPkcs1Id,
NULL, NULL, NULL);
if(encKeyNode == NULL) {
fprintf(stderr, "Error: failed to add key info\n");
goto done;
}
/* we want to put encrypted key in the <enc:CipherValue/> node */
if(xmlSecTmplEncDataEnsureCipherValue(encKeyNode) == NULL) {
fprintf(stderr, "Error: failed to add CipherValue node\n");
goto done;
}
/* add <dsig:KeyInfo/> and <dsig:KeyName/> nodes to <enc:EncryptedKey/> */
keyInfoNode2 = xmlSecTmplEncDataEnsureKeyInfo(encKeyNode, NULL);
if(keyInfoNode2 == NULL) {
fprintf(stderr, "Error: failed to add key info\n");
goto done;
}
/* set key name so we can lookup key when needed */
if(xmlSecTmplKeyInfoAddKeyName(keyInfoNode2, BAD_CAST key_name) == NULL) {
fprintf(stderr, "Error: failed to add key name\n");
goto done;
}
/* create encryption context */
encCtx = xmlSecEncCtxCreate(mngr);
if(encCtx == NULL) {
fprintf(stderr,"Error: failed to create encryption context\n");
goto done;
}
/* generate a Triple DES key */
encCtx->encKey = xmlSecKeyGenerate(xmlSecKeyDataDesId, 192, xmlSecKeyDataTypeSession);
if(encCtx->encKey == NULL) {
fprintf(stderr,"Error: failed to generate session des key\n");
goto done;
}
/* encrypt the data */
if(xmlSecEncCtxXmlEncrypt(encCtx, encDataNode, xmlDocGetRootElement(doc)) < 0) {
fprintf(stderr,"Error: encryption failed\n");
goto done;
}
/* we template is inserted in the doc */
encDataNode = NULL;
/* print encrypted data with document to stdout */
xmlDocDump(stdout, doc);
/* success */
res = 0;
done:
/* cleanup */
if(encCtx != NULL) {
xmlSecEncCtxDestroy(encCtx);
}
if(encDataNode != NULL) {
xmlFreeNode(encDataNode);
}
if(doc != NULL) {
xmlFreeDoc(doc);
}
return(res);
}
