Added XsltProcessor::setSecurityPrefs($options) and getSecurityPrefs()

to define forbidden operations within XSLT stylesheets, default is not to
enable any write operations from XSLT anymore. Bug #54446

(second iteration of the code for trunk, first commit for 5.4 branch)

6 files changed, 119 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index ae0a795ad5..745cb80b2b 100644
--- a/NEWS
+++ b/NEWS
@@ -237,6 +237,11 @@
   . Added SplObjectStorage::getHash() hook. (Etienne)
   . Added CallbackFilterIterator and RecursiveCallbackFilterIterator. (Arnaud)
 
+- Improved XSL extension:
+  . Added XsltProcessor::setSecurityPrefs($options) and getSecurityPrefs() to 
+    define forbidden operations within XSLT stylesheets, default is not to 
+    enable any write operations from XSLT anymore. Bug #54446
+
 - Improved ZLIB extension:
   . Re-implemented non-file related functionality. (Mike)
 
diff --git a/UPGRADING b/UPGRADING
index ef879668a4..72243a6794 100755
--- a/UPGRADING
+++ b/UPGRADING
@@ -176,6 +176,9 @@ UPGRADE NOTES - PHP X.Y
   var_export(), and print_r().
 - The raw data parameter in openssl_encrypt()/openssl_decrypt() is now an options
   integer rather than a boolean. A value of true produces the same behaviour.
+- Write operations within XSLT (for example with the extension sax:output) are
+  disabled by default. You can define what is forbidden with the method
+  XsltProcess::setSecurityPrefs($options)
 
 ===================================
 5. Changes made to existing methods
diff --git a/ext/xsl/php_xsl.c b/ext/xsl/php_xsl.c
index 90f45be280..13ed910b5d 100644
--- a/ext/xsl/php_xsl.c
+++ b/ext/xsl/php_xsl.c
@@ -126,6 +126,7 @@ zend_object_value xsl_objects_new(zend_class_entry *class_type TSRMLS_DC)
 	intern->node_list = NULL;
 	intern->doc = NULL;
 	intern->profiling = NULL;
+	intern->securityPrefs = XSL_SECPREF_WRITE_FILE |  XSL_SECPREF_WRITE_NETWORK | XSL_SECPREF_CREATE_DIRECTORY;
 
 	zend_object_std_init(&intern->std, class_type TSRMLS_CC);
 	object_properties_init(&intern->std, class_type);
@@ -166,6 +167,13 @@ PHP_MINIT_FUNCTION(xsl)
 	REGISTER_LONG_CONSTANT("XSL_CLONE_NEVER",    -1,     CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("XSL_CLONE_ALWAYS",    1,     CONST_CS | CONST_PERSISTENT);
 
+	REGISTER_LONG_CONSTANT("XSL_SECPREF_NONE",             XSL_SECPREF_NONE,             CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("XSL_SECPREF_READ_FILE",        XSL_SECPREF_READ_FILE,        CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("XSL_SECPREF_WRITE_FILE",       XSL_SECPREF_WRITE_FILE,       CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("XSL_SECPREF_CREATE_DIRECTORY", XSL_SECPREF_CREATE_DIRECTORY, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("XSL_SECPREF_READ_NETWORK",     XSL_SECPREF_READ_NETWORK,     CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("XSL_SECPREF_WRITE_NETWORK",    XSL_SECPREF_WRITE_NETWORK,    CONST_CS | CONST_PERSISTENT);
+
 	REGISTER_LONG_CONSTANT("LIBXSLT_VERSION",           LIBXSLT_VERSION,            CONST_CS | CONST_PERSISTENT);
 	REGISTER_STRING_CONSTANT("LIBXSLT_DOTTED_VERSION",  LIBXSLT_DOTTED_VERSION,     CONST_CS | CONST_PERSISTENT);
 
diff --git a/ext/xsl/php_xsl.h b/ext/xsl/php_xsl.h
index 5d1ffa5c3f..8782077413 100644
--- a/ext/xsl/php_xsl.h
+++ b/ext/xsl/php_xsl.h
@@ -32,6 +32,7 @@ extern zend_module_entry xsl_module_entry;
 #include <libxslt/xsltInternals.h>
 #include <libxslt/xsltutils.h>
 #include <libxslt/transform.h>
+#include <libxslt/security.h> 
 #if HAVE_XSL_EXSLT
 #include <libexslt/exslt.h>
 #include <libexslt/exsltconfig.h>
@@ -43,6 +44,13 @@ extern zend_module_entry xsl_module_entry;
 #include <libxslt/extensions.h>
 #include <libxml/xpathInternals.h>
 
+#define XSL_SECPREF_NONE 0
+#define XSL_SECPREF_READ_FILE 2
+#define XSL_SECPREF_WRITE_FILE 4
+#define XSL_SECPREF_CREATE_DIRECTORY 8
+#define XSL_SECPREF_READ_NETWORK 16
+#define XSL_SECPREF_WRITE_NETWORK 32
+
 typedef struct _xsl_object {
 	zend_object  std;
 	void *ptr;
@@ -55,6 +63,7 @@ typedef struct _xsl_object {
 	HashTable *node_list;
 	php_libxml_node_object *doc;
 	char *profiling;
+	long securityPrefs;
 } xsl_object;
 
 void php_xsl_set_object(zval *wrapper, void *obj TSRMLS_DC);
diff --git a/ext/xsl/xsl_fe.h b/ext/xsl/xsl_fe.h
index f6bc1f5ae0..a9fb16b2b2 100644
--- a/ext/xsl/xsl_fe.h
+++ b/ext/xsl/xsl_fe.h
@@ -34,6 +34,9 @@ PHP_FUNCTION(xsl_xsltprocessor_remove_parameter);
 PHP_FUNCTION(xsl_xsltprocessor_has_exslt_support);
 PHP_FUNCTION(xsl_xsltprocessor_register_php_functions);
 PHP_FUNCTION(xsl_xsltprocessor_set_profiling);
+PHP_FUNCTION(xsl_xsltprocessor_set_security_prefs);
+PHP_FUNCTION(xsl_xsltprocessor_get_security_prefs);
+
 #endif
 
 /*
diff --git a/ext/xsl/xsltprocessor.c b/ext/xsl/xsltprocessor.c
index 8cb3415167..82a223787a 100644
--- a/ext/xsl/xsltprocessor.c
+++ b/ext/xsl/xsltprocessor.c
@@ -71,6 +71,13 @@ ZEND_END_ARG_INFO();
 ZEND_BEGIN_ARG_INFO_EX(arginfo_xsl_xsltprocessor_set_profiling, 0, 0, 1)
 	ZEND_ARG_INFO(0, filename)
 ZEND_END_ARG_INFO();
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_xsl_xsltprocessor_set_security_prefs, 0, 0, 1)
+	ZEND_ARG_INFO(0, securityPrefs)
+ZEND_END_ARG_INFO();
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_xsl_xsltprocessor_get_security_prefs, 0, 0, 0)
+ZEND_END_ARG_INFO();
 /* }}} */
 
 /*
@@ -91,6 +98,8 @@ const zend_function_entry php_xsl_xsltprocessor_class_functions[] = {
 	PHP_FALIAS(hasExsltSupport, xsl_xsltprocessor_has_exslt_support, arginfo_xsl_xsltprocessor_has_exslt_support)
 	PHP_FALIAS(registerPHPFunctions, xsl_xsltprocessor_register_php_functions, arginfo_xsl_xsltprocessor_register_php_functions)
 	PHP_FALIAS(setProfiling, xsl_xsltprocessor_set_profiling, arginfo_xsl_xsltprocessor_set_profiling)
+	PHP_FALIAS(setSecurityPrefs, xsl_xsltprocessor_set_security_prefs, arginfo_xsl_xsltprocessor_set_security_prefs)
+	PHP_FALIAS(getSecurityPrefs, xsl_xsltprocessor_get_security_prefs, arginfo_xsl_xsltprocessor_get_security_prefs)
 	{NULL, NULL, NULL}
 };
 
@@ -475,6 +484,8 @@ static xmlDocPtr php_xsl_apply_stylesheet(zval *id, xsl_object *intern, xsltStyl
 	zval *doXInclude, *member;
 	zend_object_handlers *std_hnd;
 	FILE *f;
+	int secPrefsError = 0;
+	xsltSecurityPrefsPtr secPrefs = NULL;
 
 	node = php_libxml_import_node(docp TSRMLS_CC);
 	
@@ -531,11 +542,54 @@ static xmlDocPtr php_xsl_apply_stylesheet(zval *id, xsl_object *intern, xsltStyl
 	}
 	efree(member);
 
-	newdocp = xsltApplyStylesheetUser(style, doc, (const char**) params,  NULL, f, ctxt);
+	
+	//if securityPrefs is set to NONE, we don't have to do any checks, but otherwise...
+	if (intern->securityPrefs != XSL_SECPREF_NONE) {
+		secPrefs = xsltNewSecurityPrefs(); 
+		if (intern->securityPrefs & XSL_SECPREF_READ_FILE ) { 
+			if (0 != xsltSetSecurityPrefs(secPrefs, XSLT_SECPREF_READ_FILE, xsltSecurityForbid)) { 
+				secPrefsError = 1;
+			}
+		}
+		if (intern->securityPrefs & XSL_SECPREF_WRITE_FILE ) { 
+			if (0 != xsltSetSecurityPrefs(secPrefs, XSLT_SECPREF_WRITE_FILE, xsltSecurityForbid)) { 
+				secPrefsError = 1;
+			}
+		}
+		if (intern->securityPrefs & XSL_SECPREF_CREATE_DIRECTORY ) { 
+			if (0 != xsltSetSecurityPrefs(secPrefs, XSLT_SECPREF_CREATE_DIRECTORY, xsltSecurityForbid)) { 
+				secPrefsError = 1;
+			}
+		}
+		if (intern->securityPrefs & XSL_SECPREF_READ_NETWORK) { 
+			if (0 != xsltSetSecurityPrefs(secPrefs, XSLT_SECPREF_READ_NETWORK, xsltSecurityForbid)) { 
+				secPrefsError = 1;
+			}
+		}
+		if (intern->securityPrefs & XSL_SECPREF_WRITE_NETWORK) { 
+			if (0 != xsltSetSecurityPrefs(secPrefs, XSLT_SECPREF_WRITE_NETWORK, xsltSecurityForbid)) { 
+				secPrefsError = 1;
+			}
+		}
+	
+		if (0 != xsltSetCtxtSecurityPrefs(secPrefs, ctxt)) { 
+			secPrefsError = 1;
+		}
+	}
+	
+	if (secPrefsError == 1) {
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Can't set libxslt security properties, not doing transformation for security reasons");
+	} else {
+		newdocp = xsltApplyStylesheetUser(style, doc, (const char**) params,  NULL, f, ctxt);
+	}
 	if (f) {
 		fclose(f);
 	}
+	
 	xsltFreeTransformContext(ctxt);
+	if (secPrefs) {
+		xsltFreeSecurityPrefs(secPrefs);
+	}
 
 	if (intern->node_list != NULL) {
 		zend_hash_destroy(intern->node_list);
@@ -857,6 +911,42 @@ PHP_FUNCTION(xsl_xsltprocessor_set_profiling)
 }
 /* }}} end xsl_xsltprocessor_set_profiling */
 
+/* {{{ proto long xsl_xsltprocessor_set_security_prefs(long securityPrefs) */
+PHP_FUNCTION(xsl_xsltprocessor_set_security_prefs)
+{
+	zval *id;
+	xsl_object *intern;
+	DOM_GET_THIS(id);
+	long securityPrefs, oldSecurityPrefs;
+ 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &securityPrefs) == FAILURE) {
+		return;
+	}
+	intern = (xsl_object *)zend_object_store_get_object(id TSRMLS_CC);
+	oldSecurityPrefs = intern->securityPrefs; 
+	intern->securityPrefs = securityPrefs;
+	RETURN_LONG(oldSecurityPrefs);
+}
+/* }}} end xsl_xsltprocessor_set_security_prefs */
+
+/* {{{ proto long xsl_xsltprocessor_get_security_prefs() */
+PHP_FUNCTION(xsl_xsltprocessor_get_security_prefs)
+{
+	zval *id;
+	xsl_object *intern;
+	DOM_GET_THIS(id);
+	long securityPrefs;
+
+	if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, "") == SUCCESS) {
+		intern = (xsl_object *)zend_object_store_get_object(id TSRMLS_CC);
+		RETURN_LONG(intern->securityPrefs);
+	} else {
+		WRONG_PARAM_COUNT;
+	}
+}
+/* }}} end xsl_xsltprocessor_get_security_prefs */
+
+
+
 /* {{{ proto bool xsl_xsltprocessor_has_exslt_support();
 */
 PHP_FUNCTION(xsl_xsltprocessor_has_exslt_support)