diff options
| author | Paweł Sroka <srokap@gmail.com> | 2014-01-01 13:12:24 +0100 |
|---|---|---|
| committer | Paweł Sroka <srokap@gmail.com> | 2014-01-01 13:12:24 +0100 |
| commit | 53509917fd2119e17209179aae6d54b64dd2d244 (patch) | |
| tree | aac2e883578b78796686728ae3beed5b2a35a9a4 | |
| parent | 7006294fcbfab450289403b6519edb9d5d30ff35 (diff) | |
| parent | 7cacdc8bc26c98a58dc8986acfd911d6542608af (diff) | |
| download | elgg-53509917fd2119e17209179aae6d54b64dd2d244.tar.gz elgg-53509917fd2119e17209179aae6d54b64dd2d244.tar.bz2 | |
Merged in libxml18 (pull request #8)
Disable loading external entities during XML parsing
| -rw-r--r-- | engine/classes/ElggAutoP.php | 14 | ||||
| -rw-r--r-- | engine/classes/ElggXMLElement.php | 8 | ||||
| -rw-r--r-- | engine/tests/regression/trac_bugs.php | 29 | ||||
| -rw-r--r-- | engine/tests/test_files/xxe/external_entity.txt | 1 | ||||
| -rw-r--r-- | engine/tests/test_files/xxe/request.xml | 8 |
5 files changed, 58 insertions, 2 deletions
diff --git a/engine/classes/ElggAutoP.php b/engine/classes/ElggAutoP.php index 71536c433..05842d1b2 100644 --- a/engine/classes/ElggAutoP.php +++ b/engine/classes/ElggAutoP.php @@ -110,12 +110,19 @@ class ElggAutoP { // http://www.php.net/manual/en/domdocument.loadhtml.php#95463 libxml_use_internal_errors(true); + // Do not load entities. May be unnecessary, better safe than sorry + $disable_load_entities = libxml_disable_entity_loader(true); + if (!$this->_doc->loadHTML("<html><meta http-equiv='content-type' " . "content='text/html; charset={$this->encoding}'><body>{$html}</body>" . "</html>")) { + + libxml_disable_entity_loader($disable_load_entities); return false; } + libxml_disable_entity_loader($disable_load_entities); + $this->_xpath = new DOMXPath($this->_doc); // start processing recursively at the BODY element $nodeList = $this->_xpath->query('//body[1]'); @@ -135,9 +142,16 @@ class ElggAutoP { // re-parse so we can handle new AUTOP elements + // Do not load entities. May be unnecessary, better safe than sorry + $disable_load_entities = libxml_disable_entity_loader(true); + if (!$this->_doc->loadHTML($html)) { + libxml_disable_entity_loader($disable_load_entities); return false; } + + libxml_disable_entity_loader($disable_load_entities); + // must re-create XPath object after DOM load $this->_xpath = new DOMXPath($this->_doc); diff --git a/engine/classes/ElggXMLElement.php b/engine/classes/ElggXMLElement.php index 6f2633e25..cbd3fc5ce 100644 --- a/engine/classes/ElggXMLElement.php +++ b/engine/classes/ElggXMLElement.php @@ -20,7 +20,12 @@ class ElggXMLElement { if ($xml instanceof SimpleXMLElement) { $this->_element = $xml; } else { + // do not load entities + $disable_load_entities = libxml_disable_entity_loader(true); + $this->_element = new SimpleXMLElement($xml); + + libxml_disable_entity_loader($disable_load_entities); } } @@ -123,5 +128,4 @@ class ElggXMLElement { } return false; } - -}
\ No newline at end of file +} diff --git a/engine/tests/regression/trac_bugs.php b/engine/tests/regression/trac_bugs.php index ef1348cf6..689275661 100644 --- a/engine/tests/regression/trac_bugs.php +++ b/engine/tests/regression/trac_bugs.php @@ -373,4 +373,33 @@ class ElggCoreRegressionBugsTest extends ElggCoreUnitTest { //delete group and annotations $group->delete(); } + + public function test_ElggXMLElement_does_not_load_external_entities() { + $elLast = libxml_disable_entity_loader(false); + + // build payload that should trigger loading of external entity + $payload = file_get_contents(dirname(dirname(__FILE__)) . '/test_files/xxe/request.xml'); + $path = realpath(dirname(dirname(__FILE__)) . '/test_files/xxe/external_entity.txt'); + $path = str_replace('\\', '/', $path); + if ($path[0] != '/') { + $path = '/' . $path; + } + $path = 'file://' . $path; + $payload = sprintf($payload, $path); + + // make sure we can actually this in this environment + $element = new SimpleXMLElement($payload); + $can_load_entity = preg_match('/secret/', (string)$element->methodName); + + $this->skipUnless($can_load_entity, "XXE vulnerability cannot be tested on this system"); + + if ($can_load_entity) { + $el = new ElggXMLElement($payload); + $chidren = $el->getChildren(); + $content = $chidren[0]->getContent(); + $this->assertNoPattern('/secret/', $content); + } + + libxml_disable_entity_loader($elLast); + } } diff --git a/engine/tests/test_files/xxe/external_entity.txt b/engine/tests/test_files/xxe/external_entity.txt new file mode 100644 index 000000000..536aca34d --- /dev/null +++ b/engine/tests/test_files/xxe/external_entity.txt @@ -0,0 +1 @@ +secret
\ No newline at end of file diff --git a/engine/tests/test_files/xxe/request.xml b/engine/tests/test_files/xxe/request.xml new file mode 100644 index 000000000..4390f9db2 --- /dev/null +++ b/engine/tests/test_files/xxe/request.xml @@ -0,0 +1,8 @@ +<?xml version="1.0"?> +<!DOCTYPE foo [ +<!ELEMENT methodName ANY > +<!ENTITY xxe SYSTEM "%s" > +]> +<methodCall> + <methodName>test&xxe;test</methodName> +</methodCall> |