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/**
* XML Security Library example: CGI verification script.
*
* This is free software; 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 <assert.h>
#include <dirent.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/xmldsig.h>
#include <xmlsec/crypto.h>
/* #define XMLDSIGVERIFY_DEFAULT_TRUSTED_CERTS_FOLDER "/etc/httpd/conf/ssl.crt" */
#define XMLDSIGVERIFY_DEFAULT_TRUSTED_CERTS_FOLDER "/var/www/cgi-bin/keys-certs.def"
#define XMLDSIGVERIFY_KEY_AND_CERTS_FOLDER "/var/www/cgi-bin/keys-certs"
int load_keys(xmlSecKeysMngrPtr mngr, const char* path, int report_loaded_keys);
int load_trusted_certs(xmlSecKeysMngrPtr mngr, const char* path, int report_loaded_certs);
int verify_request(xmlSecKeysMngrPtr mngr);
int url_decode(char *buf, size_t size);
int
main(int argc, char **argv) {
xmlSecKeysMngrPtr mngr;
#ifndef XMLSEC_NO_XSLT
xsltSecurityPrefsPtr xsltSecPrefs = NULL;
#endif /* XMLSEC_NO_XSLT */
/* start response */
fprintf(stdout, "Content-type: text/plain\n");
fprintf(stdout, "\n");
/* 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 */
/* make sure that we print out everything to stdout */
xmlGenericErrorContext = stdout;
/* 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(stdout, "Error: xmlsec initialization failed.\n");
return(-1);
}
/* Check loaded library version */
if(xmlSecCheckVersion() != 1) {
fprintf(stdout, "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(stdout, "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(XMLDSIGVERIFY_DEFAULT_TRUSTED_CERTS_FOLDER) < 0) {
fprintf(stdout, "Error: crypto initialization failed.\n");
return(-1);
}
/* Init xmlsec-crypto library */
if(xmlSecCryptoInit() < 0) {
fprintf(stdout, "Error: xmlsec-crypto initialization failed.\n");
return(-1);
}
/* create keys manager */
mngr = xmlSecKeysMngrCreate();
if(mngr == NULL) {
fprintf(stdout, "Error: failed to create keys manager.\n");
return(-1);
}
if(xmlSecCryptoAppDefaultKeysMngrInit(mngr) < 0) {
fprintf(stdout, "Error: failed to initialize keys manager.\n");
return(-1);
}
if(load_keys(mngr, XMLDSIGVERIFY_KEY_AND_CERTS_FOLDER, 0) < 0) {
xmlSecKeysMngrDestroy(mngr);
return(-1);
}
if(load_trusted_certs(mngr, XMLDSIGVERIFY_KEY_AND_CERTS_FOLDER, 0) < 0) {
xmlSecKeysMngrDestroy(mngr);
return(-1);
}
if(verify_request(mngr) < 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_trusted_certs:
* @mngr: the keys manager.
* @path: the path to a folder that contains trusted certificates.
*
* Loads trusted certificates from @path.
*
* Returns 0 on success or a negative value if an error occurs.
*/
int load_trusted_certs(xmlSecKeysMngrPtr mngr, const char* path, int report_loaded_certs) {
DIR* dir;
struct dirent* entry;
char filename[256];
int len;
assert(mngr);
assert(path);
dir = opendir(path);
if(dir == NULL) {
fprintf(stdout, "Error: failed to open folder \"%s\".\n", path);
return(-1);
}
while((entry = readdir(dir)) != NULL) {
assert(entry->d_name);
len = strlen(entry->d_name);
if((len > 4) && (strcmp(entry->d_name + len - 4, ".pem") == 0)) {
snprintf(filename, sizeof(filename), "%s/%s", path, entry->d_name);
if(xmlSecCryptoAppKeysMngrCertLoad(mngr, filename, xmlSecKeyDataFormatPem, xmlSecKeyDataTypeTrusted) < 0) {
fprintf(stdout,"Error: failed to load pem certificate from \"%s\"\n", filename);
closedir(dir);
return(-1);
}
if(report_loaded_certs) {
fprintf(stdout, "Loaded trusted certificate from \"%s\"...\n", filename);
}
} else if((len > 4) && (strcmp(entry->d_name + len - 4, ".der") == 0)) {
snprintf(filename, sizeof(filename), "%s/%s", path, entry->d_name);
if(xmlSecCryptoAppKeysMngrCertLoad(mngr, filename, xmlSecKeyDataFormatDer, xmlSecKeyDataTypeTrusted) < 0) {
fprintf(stdout,"Error: failed to load der certificate from \"%s\"\n", filename);
closedir(dir);
return(-1);
}
if(report_loaded_certs) {
fprintf(stdout, "Loaded trusted certificate from \"%s\"...\n", filename);
}
}
}
closedir(dir);
return(0);
}
int load_keys(xmlSecKeysMngrPtr mngr, const char* path, int report_loaded_keys) {
char filename[256];
assert(mngr);
snprintf(filename, sizeof(filename), "%s/keys.xml", path);
if(xmlSecCryptoAppDefaultKeysMngrLoad(mngr, filename) < 0) {
fprintf(stdout,"Error: failed to load keys from \"%s\"\n", filename);
return(-1);
}
if(report_loaded_keys) {
fprintf(stdout, "Loaded keys from \"%s\"...\n", filename);
}
return(0);
}
/**
* verify_request:
* @mng: the keys manager
*
* Verifies XML signature in the request (stdin).
*
* Returns 0 on success or a negative value if an error occurs.
*/
int
verify_request(xmlSecKeysMngrPtr mngr) {
xmlBufferPtr buffer = NULL;
char buf[256];
xmlDocPtr doc = NULL;
xmlNodePtr node = NULL;
xmlSecDSigCtxPtr dsigCtx = NULL;
int ret;
int res = -1;
assert(mngr);
/* load request in the buffer */
buffer = xmlBufferCreate();
if(buffer == NULL) {
fprintf(stdout,"Error: failed to create buffer\n");
goto done;
}
while(!feof(stdin)) {
ret = fread(buf, 1, sizeof(buf), stdin);
if(ret < 0) {
fprintf(stdout,"Error: read failed\n");
goto done;
}
xmlBufferAdd(buffer, buf, ret);
}
/* is the document subbmitted from the form? */
if(strncmp((char*)xmlBufferContent(buffer), "_xmldoc=", 8) == 0) {
xmlBufferShrink(buffer, 8);
buffer->use = url_decode((char*)xmlBufferContent(buffer), xmlBufferLength(buffer));
}
/**
* Load doc
*/
doc = xmlReadMemory(xmlBufferContent(buffer), xmlBufferLength(buffer),
NULL, NULL,
XML_PARSE_NOENT | XML_PARSE_NOCDATA |
XML_PARSE_PEDANTIC | XML_PARSE_NOCDATA);
if (doc == NULL) {
fprintf(stdout, "Error: unable to parse xml document (syntax error)\n");
goto done;
}
/*
* Check the document is of the right kind
*/
if(xmlDocGetRootElement(doc) == NULL) {
fprintf(stdout,"Error: empty document\n");
goto done;
}
/* find start node */
node = xmlSecFindNode(xmlDocGetRootElement(doc), xmlSecNodeSignature, xmlSecDSigNs);
if(node == NULL) {
fprintf(stdout, "Error: start <dsig:Signature/> node not found\n");
goto done;
}
/* create signature context */
dsigCtx = xmlSecDSigCtxCreate(mngr);
if(dsigCtx == NULL) {
fprintf(stdout,"Error: failed to create signature context\n");
goto done;
}
/* we would like to store and print out everything */
/* actually we would not because it opens a security hole
dsigCtx->flags = XMLSEC_DSIG_FLAGS_STORE_SIGNEDINFO_REFERENCES |
XMLSEC_DSIG_FLAGS_STORE_MANIFEST_REFERENCES |
XMLSEC_DSIG_FLAGS_STORE_SIGNATURE;
*/
/* Verify signature */
if(xmlSecDSigCtxVerify(dsigCtx, node) < 0) {
fprintf(stdout,"Error: signature verification failed\n");
goto done;
}
/* print verification result to stdout */
if(dsigCtx->status == xmlSecDSigStatusSucceeded) {
fprintf(stdout, "RESULT: Signature is OK\n");
} else {
fprintf(stdout, "RESULT: Signature is INVALID\n");
}
fprintf(stdout, "---------------------------------------------------\n");
xmlSecDSigCtxDebugDump(dsigCtx, stdout);
/* success */
res = 0;
done:
/* cleanup */
if(dsigCtx != NULL) {
xmlSecDSigCtxDestroy(dsigCtx);
}
if(doc != NULL) {
xmlFreeDoc(doc);
}
if(buffer != NULL) {
xmlBufferFree(buffer);
}
return(res);
}
/* not the best way to do it */
#define toHex(c) ( ( ('0' <= (c)) && ((c) <= '9') ) ? (c) - '0' : \
( ( ('A' <= (c)) && ((c) <= 'F') ) ? (c) - 'A' + 10 : 0 ) )
/**
* url_decode:
* @buf: the input buffer.
* @size: the input buffer size.
*
* Does url decoding in-place.
*
* Returns length of the decoded result on success or
* a negative value if an error occurs.
*/
int url_decode(char *buf, size_t size) {
char *p1, *p2;
assert(buf);
p1 = p2 = buf;
while(p1 - buf < size) {
if(((*p1) == '%') && ((p1 - buf) <= (size - 3))) {
*(p2++) = (char)(toHex(p1[1]) * 16 + toHex(p1[2]));
p1 += 3;
} else if((*p1) == '+') {
*(p2++) = ' ';
p1++;
} else {
*(p2++) = *(p1++);
}
}
return(p2 - buf);
}
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