<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Writing a custom keys manager.</title> <meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.79"> <link rel="HOME" title="XML Security Library Reference Manual" href="index.html"> <link rel="UP" title="Examples." href="xmlsec-examples.html"> <link rel="PREVIOUS" title="Decrypting data with keys manager." href="xmlsec-decrypt-with-keys-mngr.html"> <link rel="NEXT" title="APPENDIX A. 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see Copyright file in the source * distribution for preciese wording. * * Copyright (C) 2002-2003 Aleksey Sanin <aleksey@aleksey.com> */ #include <stdlib.h> #include <string.h> #include <ctype.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> xmlSecKeyStoreId files_keys_store_get_klass(void); xmlSecKeysMngrPtr create_files_keys_mngr(void); 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 != 2) { fprintf(stderr, "Error: wrong number of arguments.\n"); fprintf(stderr, "Usage: %s <enc-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(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); } /* create keys manager and load keys */ mngr = create_files_keys_mngr(); 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); } /** * 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 (%d 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); } /** * create_files_keys_mngr: * * Creates a files based keys manager: we assume that key name is * the key file name, * * Returns pointer to newly created keys manager or NULL if an error occurs. */ xmlSecKeysMngrPtr create_files_keys_mngr(void) { xmlSecKeyStorePtr keysStore; xmlSecKeysMngrPtr mngr; /* create files based keys store */ keysStore = xmlSecKeyStoreCreate(files_keys_store_get_klass()); if(keysStore == NULL) { fprintf(stderr, "Error: failed to create keys store.\n"); return(NULL); } /* create keys manager */ mngr = xmlSecKeysMngrCreate(); if(mngr == NULL) { fprintf(stderr, "Error: failed to create keys manager.\n"); xmlSecKeyStoreDestroy(keysStore); return(NULL); } /* add store to keys manager, from now on keys manager destroys the store if needed */ if(xmlSecKeysMngrAdoptKeysStore(mngr, keysStore) < 0) { fprintf(stderr, "Error: failed to add keys store to keys manager.\n"); xmlSecKeyStoreDestroy(keysStore); xmlSecKeysMngrDestroy(mngr); return(NULL); } /* initialize crypto library specific data in keys manager */ if(xmlSecCryptoKeysMngrInit(mngr) < 0) { fprintf(stderr, "Error: failed to initialize crypto data in keys manager.\n"); xmlSecKeysMngrDestroy(mngr); return(NULL); } /* set the get key callback */ mngr->getKey = xmlSecKeysMngrGetKey; return(mngr); } /**************************************************************************** * * Files Keys Store: we assume that key's name (content of the * <dsig:KeyName/> element is a name of the file with a key (in the * current folder). * Attention: this probably not a good solution for high traffic systems. * ***************************************************************************/ static xmlSecKeyPtr files_keys_store_find_key (xmlSecKeyStorePtr store, const xmlChar* name, xmlSecKeyInfoCtxPtr keyInfoCtx); static xmlSecKeyStoreKlass files_keys_store_klass = { sizeof(xmlSecKeyStoreKlass), sizeof(xmlSecKeyStore), BAD_CAST "files-based-keys-store", /* const xmlChar* name; */ NULL, /* xmlSecKeyStoreInitializeMethod initialize; */ NULL, /* xmlSecKeyStoreFinalizeMethod finalize; */ files_keys_store_find_key, /* xmlSecKeyStoreFindKeyMethod findKey; */ /* reserved for the future */ NULL, /* void* reserved0; */ NULL, /* void* reserved1; */ }; /** * files_keys_store_get_klass: * * The files based keys store klass: we assume that key name is the * key file name, * * Returns files based keys store klass. */ xmlSecKeyStoreId files_keys_store_get_klass(void) { return(&files_keys_store_klass); } /** * files_keys_store_find_key: * @store: the pointer to simple keys store. * @name: the desired key name. * @keyInfoCtx: the pointer to <dsig:KeyInfo/> node processing context. * * Lookups key in the @store. The caller is responsible for destroying * returned key with #xmlSecKeyDestroy function. * * Returns pointer to key or NULL if key not found or an error occurs. */ static xmlSecKeyPtr files_keys_store_find_key(xmlSecKeyStorePtr store, const xmlChar* name, xmlSecKeyInfoCtxPtr keyInfoCtx) { xmlSecKeyPtr key; const xmlChar* p; assert(store); assert(keyInfoCtx); /* it's possible to do not have the key name or desired key type * but we could do nothing in this case */ if((name == NULL) || (keyInfoCtx->keyReq.keyId == xmlSecKeyDataIdUnknown)){ return(NULL); } /* we don't want to open files in a folder other than "current"; * to prevent it limit the characters in the key name to alpha/digit, * '.', '-' or '_'. */ for(p = name; (*p) != '\0'; ++p) { if(!isalnum((*p)) && ((*p) != '.') && ((*p) != '-') && ((*p) != '_')) { return(NULL); } } if((keyInfoCtx->keyReq.keyId == xmlSecKeyDataDsaId) || (keyInfoCtx->keyReq.keyId == xmlSecKeyDataRsaId)) { /* load key from a pem file, if key is not found then it's an error (is it?) */ key = xmlSecCryptoAppKeyLoad(name, xmlSecKeyDataFormatPem, NULL, NULL, NULL); if(key == NULL) { fprintf(stderr,"Error: failed to load public pem key from \"%s\"\n", name); return(NULL); } } else { /* otherwise it's a binary key, if key is not found then it's an error (is it?) */ key = xmlSecKeyReadBinaryFile(keyInfoCtx->keyReq.keyId, name); if(key == NULL) { fprintf(stderr,"Error: failed to load key from binary file \"%s\"\n", name); return(NULL); } } /* set key name */ if(xmlSecKeySetName(key, name) < 0) { fprintf(stderr,"Error: failed to set key name for key from \"%s\"\n", name); xmlSecKeyDestroy(key); return(NULL); } return(key); } </pre> <p></p> </div> </div> </div> <table class="navigation" width="100%" summary="Navigation footer" cellpadding="2" cellspacing="2"><tr valign="middle"> <td align="left"><a accesskey="p" href="xmlsec-decrypt-with-keys-mngr.html"><b><<< Decrypting data with keys manager.</b></a></td> <td align="right"><a accesskey="n" href="xmlsec-signature-klasses.html"><b>APPENDIX A. 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