/**
* XML Security Library example: Decrypting an encrypted file using keys manager.
*
* Decrypts encrypted XML file using keys manager and a list of
* DES key from a binary file
*
* Usage:
* ./decrypt2 <xml-enc> <des-key-file1> [<des-key-file2> [...]]
*
* Example:
* ./decrypt2 encrypt1-res.xml deskey.bin
* ./decrypt2 encrypt2-res.xml deskey.bin
*
* This is free software; see Copyright file in the source
* distribution for preciese wording.
*
* Copyright (C) 2002-2022 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/crypto.h>
xmlSecKeysMngrPtr load_des_keys(char** files, int files_size);
int decrypt_file(xmlSecKeysMngrPtr mngr, const char* enc_file);
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 <enc-file> <key-file1> [<key-file2> [...]]\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_des_keys(&(argv[2]), argc - 2);
if(mngr == NULL) {
return(-1);
}
if(decrypt_file(mngr, argv[1]) < 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_des_keys:
* @files: the list of filenames.
* @files_size: the number of filenames in #files.
*
* Creates simple keys manager and load DES keys from #files 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_des_keys(char** files, int files_size) {
xmlSecKeysMngrPtr mngr;
xmlSecKeyPtr key;
int i;
assert(files);
assert(files_size > 0);
/* 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);
}
for(i = 0; i < files_size; ++i) {
assert(files[i]);
/* load DES key */
key = xmlSecKeyReadBinaryFile(xmlSecKeyDataDesId, files[i]);
if(key == NULL) {
fprintf(stderr,"Error: failed to load des key from binary file \"%s\"\n", files[i]);
xmlSecKeysMngrDestroy(mngr);
return(NULL);
}
/* set key name to the file name, this is just an example! */
if(xmlSecKeySetName(key, BAD_CAST files[i]) < 0) {
fprintf(stderr,"Error: failed to set key name for key from \"%s\"\n", files[i]);
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", files[i]);
xmlSecKeyDestroy(key);
xmlSecKeysMngrDestroy(mngr);
return(NULL);
}
}
return(mngr);
}
/**
* decrypt_file:
* @mngr: the pointer to keys manager.
* @enc_file: the encrypted XML file name.
*
* Decrypts the XML file #enc_file using DES key from #key_file and
* prints results to stdout.
*
* Returns 0 on success or a negative value if an error occurs.
*/
int
decrypt_file(xmlSecKeysMngrPtr mngr, const char* enc_file) {
xmlDocPtr doc = NULL;
xmlNodePtr node = NULL;
xmlSecEncCtxPtr encCtx = NULL;
int res = -1;
assert(mngr);
assert(enc_file);
/* load template */
doc = xmlParseFile(enc_file);
if ((doc == NULL) || (xmlDocGetRootElement(doc) == NULL)){
fprintf(stderr, "Error: unable to parse file \"%s\"\n", enc_file);
goto done;
}
/* find start node */
node = xmlSecFindNode(xmlDocGetRootElement(doc), xmlSecNodeEncryptedData, xmlSecEncNs);
if(node == NULL) {
fprintf(stderr, "Error: start node not found in \"%s\"\n", enc_file);
goto done;
}
/* create encryption context */
encCtx = xmlSecEncCtxCreate(mngr);
if(encCtx == NULL) {
fprintf(stderr,"Error: failed to create encryption context\n");
goto done;
}
/* decrypt the data */
if((xmlSecEncCtxDecrypt(encCtx, node) < 0) || (encCtx->result == NULL)) {
fprintf(stderr,"Error: decryption failed\n");
goto done;
}
/* print decrypted data to stdout */
if(encCtx->resultReplaced != 0) {
fprintf(stdout, "Decrypted XML data:\n");
xmlDocDump(stdout, doc);
} else {
fprintf(stdout, "Decrypted binary data (" XMLSEC_SIZE_FMT " bytes):\n",
xmlSecBufferGetSize(encCtx->result));
if(xmlSecBufferGetData(encCtx->result) != NULL) {
fwrite(xmlSecBufferGetData(encCtx->result),
1,
xmlSecBufferGetSize(encCtx->result),
stdout);
}
}
fprintf(stdout, "\n");
/* success */
res = 0;
done:
/* cleanup */
if(encCtx != NULL) {
xmlSecEncCtxDestroy(encCtx);
}
if(doc != NULL) {
xmlFreeDoc(doc);
}
return(res);
}
