<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>[192758] trunk/Source/WebCore</title>
</head>
<body>
<style type="text/css"><!--
#msg dl.meta { border: 1px #006 solid; background: #369; padding: 6px; color: #fff; }
#msg dl.meta dt { float: left; width: 6em; font-weight: bold; }
#msg dt:after { content:':';}
#msg dl, #msg dt, #msg ul, #msg li, #header, #footer, #logmsg { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt; }
#msg dl a { font-weight: bold}
#msg dl a:link { color:#fc3; }
#msg dl a:active { color:#ff0; }
#msg dl a:visited { color:#cc6; }
h3 { font-family: verdana,arial,helvetica,sans-serif; font-size: 10pt; font-weight: bold; }
#msg pre { overflow: auto; background: #ffc; border: 1px #fa0 solid; padding: 6px; }
#logmsg { background: #ffc; border: 1px #fa0 solid; padding: 1em 1em 0 1em; }
#logmsg p, #logmsg pre, #logmsg blockquote { margin: 0 0 1em 0; }
#logmsg p, #logmsg li, #logmsg dt, #logmsg dd { line-height: 14pt; }
#logmsg h1, #logmsg h2, #logmsg h3, #logmsg h4, #logmsg h5, #logmsg h6 { margin: .5em 0; }
#logmsg h1:first-child, #logmsg h2:first-child, #logmsg h3:first-child, #logmsg h4:first-child, #logmsg h5:first-child, #logmsg h6:first-child { margin-top: 0; }
#logmsg ul, #logmsg ol { padding: 0; list-style-position: inside; margin: 0 0 0 1em; }
#logmsg ul { text-indent: -1em; padding-left: 1em; }#logmsg ol { text-indent: -1.5em; padding-left: 1.5em; }
#logmsg > ul, #logmsg > ol { margin: 0 0 1em 0; }
#logmsg pre { background: #eee; padding: 1em; }
#logmsg blockquote { border: 1px solid #fa0; border-left-width: 10px; padding: 1em 1em 0 1em; background: white;}
#logmsg dl { margin: 0; }
#logmsg dt { font-weight: bold; }
#logmsg dd { margin: 0; padding: 0 0 0.5em 0; }
#logmsg dd:before { content:'\00bb';}
#logmsg table { border-spacing: 0px; border-collapse: collapse; border-top: 4px solid #fa0; border-bottom: 1px solid #fa0; background: #fff; }
#logmsg table th { text-align: left; font-weight: normal; padding: 0.2em 0.5em; border-top: 1px dotted #fa0; }
#logmsg table td { text-align: right; border-top: 1px dotted #fa0; padding: 0.2em 0.5em; }
#logmsg table thead th { text-align: center; border-bottom: 1px solid #fa0; }
#logmsg table th.Corner { text-align: left; }
#logmsg hr { border: none 0; border-top: 2px dashed #fa0; height: 1px; }
#header, #footer { color: #fff; background: #636; border: 1px #300 solid; padding: 6px; }
#patch { width: 100%; }
#patch h4 {font-family: verdana,arial,helvetica,sans-serif;font-size:10pt;padding:8px;background:#369;color:#fff;margin:0;}
#patch .propset h4, #patch .binary h4 {margin:0;}
#patch pre {padding:0;line-height:1.2em;margin:0;}
#patch .diff {width:100%;background:#eee;padding: 0 0 10px 0;overflow:auto;}
#patch .propset .diff, #patch .binary .diff {padding:10px 0;}
#patch span {display:block;padding:0 10px;}
#patch .modfile, #patch .addfile, #patch .delfile, #patch .propset, #patch .binary, #patch .copfile {border:1px solid #ccc;margin:10px 0;}
#patch ins {background:#dfd;text-decoration:none;display:block;padding:0 10px;}
#patch del {background:#fdd;text-decoration:none;display:block;padding:0 10px;}
#patch .lines, .info {color:#888;background:#fff;}
--></style>
<div id="msg">
<dl class="meta">
<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/192758">192758</a></dd>
<dt>Author</dt> <dd>ddkilzer@apple.com</dd>
<dt>Date</dt> <dd>2015-11-23 19:30:03 -0800 (Mon, 23 Nov 2015)</dd>
</dl>
<h3>Log Message</h3>
<pre>Hardening against CSSSelector double frees
<http://webkit.org/b/56124>
<rdar://problem/9119036>
Reviewed by Antti Koivisto.
Add some security assertions to catch this issue if it ever
happens in Debug builds, and make changes in
CSSSelector::~CSSSelector() and
CSSSelectorList::deleteSelectors() to prevent obvious issues if
they're ever called twice in Release builds.
No new tests because we don't know how to reproduce this.
* css/CSSSelector.cpp:
(WebCore::CSSSelector::CSSSelector): Initialize
m_destructorHasBeenCalled.
* css/CSSSelector.h:
(WebCore::CSSSelector::m_destructorHasBeenCalled): Add bitfield.
(WebCore::CSSSelector::CSSSelector): Initialize
m_destructorHasBeenCalled.
(WebCore::CSSSelector::~CSSSelector): Add security assertion
that this is never called twice. Clear out any fields that
would have caused us to dereference an object twice.
* css/CSSSelectorList.cpp:
(WebCore::CSSSelectorList::deleteSelectors): Clear
m_selectorArray when freeing the memory to which it was
pointing. This prevents re-entrancy issues or calling this
method twice on the same thread. Also restructure the for()
loop to prevent calling CSSSelector::isLastInSelectorList()
after CSSSelector::~CSSSelector() has been called (via CRBug
241892).</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWebCoreChangeLog">trunk/Source/WebCore/ChangeLog</a></li>
<li><a href="#trunkSourceWebCorecssCSSSelectorcpp">trunk/Source/WebCore/css/CSSSelector.cpp</a></li>
<li><a href="#trunkSourceWebCorecssCSSSelectorh">trunk/Source/WebCore/css/CSSSelector.h</a></li>
<li><a href="#trunkSourceWebCorecssCSSSelectorListcpp">trunk/Source/WebCore/css/CSSSelectorList.cpp</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/ChangeLog (192757 => 192758)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/ChangeLog 2015-11-24 02:53:28 UTC (rev 192757)
+++ trunk/Source/WebCore/ChangeLog 2015-11-24 03:30:03 UTC (rev 192758)
</span><span class="lines">@@ -1,3 +1,39 @@
</span><ins>+2015-11-23 David Kilzer <ddkilzer@apple.com>
+
+ Hardening against CSSSelector double frees
+ <http://webkit.org/b/56124>
+ <rdar://problem/9119036>
+
+ Reviewed by Antti Koivisto.
+
+ Add some security assertions to catch this issue if it ever
+ happens in Debug builds, and make changes in
+ CSSSelector::~CSSSelector() and
+ CSSSelectorList::deleteSelectors() to prevent obvious issues if
+ they're ever called twice in Release builds.
+
+ No new tests because we don't know how to reproduce this.
+
+ * css/CSSSelector.cpp:
+ (WebCore::CSSSelector::CSSSelector): Initialize
+ m_destructorHasBeenCalled.
+ * css/CSSSelector.h:
+ (WebCore::CSSSelector::m_destructorHasBeenCalled): Add bitfield.
+ (WebCore::CSSSelector::CSSSelector): Initialize
+ m_destructorHasBeenCalled.
+ (WebCore::CSSSelector::~CSSSelector): Add security assertion
+ that this is never called twice. Clear out any fields that
+ would have caused us to dereference an object twice.
+
+ * css/CSSSelectorList.cpp:
+ (WebCore::CSSSelectorList::deleteSelectors): Clear
+ m_selectorArray when freeing the memory to which it was
+ pointing. This prevents re-entrancy issues or calling this
+ method twice on the same thread. Also restructure the for()
+ loop to prevent calling CSSSelector::isLastInSelectorList()
+ after CSSSelector::~CSSSelector() has been called (via CRBug
+ 241892).
+
</ins><span class="cx"> 2015-11-23 Brian Burg <bburg@apple.com>
</span><span class="cx">
</span><span class="cx"> Web Inspector: inspector settings should not be shared between different inspection levels
</span></span></pre></div>
<a id="trunkSourceWebCorecssCSSSelectorcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/CSSSelector.cpp (192757 => 192758)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/CSSSelector.cpp 2015-11-24 02:53:28 UTC (rev 192757)
+++ trunk/Source/WebCore/css/CSSSelector.cpp 2015-11-24 03:30:03 UTC (rev 192758)
</span><span class="lines">@@ -64,6 +64,9 @@
</span><span class="cx"> , m_descendantDoubleChildSyntax(false)
</span><span class="cx"> #endif
</span><span class="cx"> , m_caseInsensitiveAttributeValueMatching(false)
</span><ins>+#if !ASSERT_WITH_SECURITY_IMPLICATION_DISABLED
+ , m_destructorHasBeenCalled(false)
+#endif
</ins><span class="cx"> {
</span><span class="cx"> const AtomicString& tagLocalName = tagQName.localName();
</span><span class="cx"> const AtomicString tagLocalNameASCIILowercase = tagLocalName.convertToASCIILowercase();
</span></span></pre></div>
<a id="trunkSourceWebCorecssCSSSelectorh"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/CSSSelector.h (192757 => 192758)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/CSSSelector.h 2015-11-24 02:53:28 UTC (rev 192757)
+++ trunk/Source/WebCore/css/CSSSelector.h 2015-11-24 03:30:03 UTC (rev 192758)
</span><span class="lines">@@ -324,6 +324,9 @@
</span><span class="cx"> unsigned m_descendantDoubleChildSyntax : 1;
</span><span class="cx"> #endif
</span><span class="cx"> unsigned m_caseInsensitiveAttributeValueMatching : 1;
</span><ins>+#if !ASSERT_WITH_SECURITY_IMPLICATION_DISABLED
+ unsigned m_destructorHasBeenCalled : 1;
+#endif
</ins><span class="cx">
</span><span class="cx"> unsigned simpleSelectorSpecificityForPage() const;
</span><span class="cx">
</span><span class="lines">@@ -466,6 +469,9 @@
</span><span class="cx"> , m_descendantDoubleChildSyntax(false)
</span><span class="cx"> #endif
</span><span class="cx"> , m_caseInsensitiveAttributeValueMatching(false)
</span><ins>+#if !ASSERT_WITH_SECURITY_IMPLICATION_DISABLED
+ , m_destructorHasBeenCalled(false)
+#endif
</ins><span class="cx"> {
</span><span class="cx"> }
</span><span class="cx">
</span><span class="lines">@@ -484,6 +490,9 @@
</span><span class="cx"> , m_descendantDoubleChildSyntax(o.m_descendantDoubleChildSyntax)
</span><span class="cx"> #endif
</span><span class="cx"> , m_caseInsensitiveAttributeValueMatching(o.m_caseInsensitiveAttributeValueMatching)
</span><ins>+#if !ASSERT_WITH_SECURITY_IMPLICATION_DISABLED
+ , m_destructorHasBeenCalled(false)
+#endif
</ins><span class="cx"> {
</span><span class="cx"> if (o.m_hasRareData) {
</span><span class="cx"> m_data.m_rareData = o.m_data.m_rareData;
</span><span class="lines">@@ -502,14 +511,26 @@
</span><span class="cx">
</span><span class="cx"> inline CSSSelector::~CSSSelector()
</span><span class="cx"> {
</span><del>- if (m_hasRareData)
</del><ins>+ ASSERT_WITH_SECURITY_IMPLICATION(!m_destructorHasBeenCalled);
+#if !ASSERT_WITH_SECURITY_IMPLICATION_DISABLED
+ m_destructorHasBeenCalled = true;
+#endif
+ if (m_hasRareData) {
</ins><span class="cx"> m_data.m_rareData->deref();
</span><del>- else if (m_hasNameWithCase)
</del><ins>+ m_data.m_rareData = nullptr;
+ m_hasRareData = false;
+ } else if (m_hasNameWithCase) {
</ins><span class="cx"> m_data.m_nameWithCase->deref();
</span><del>- else if (match() == Tag)
</del><ins>+ m_data.m_nameWithCase = nullptr;
+ m_hasNameWithCase = false;
+ } else if (match() == Tag) {
</ins><span class="cx"> m_data.m_tagQName->deref();
</span><del>- else if (m_data.m_value)
</del><ins>+ m_data.m_tagQName = nullptr;
+ m_match = Unknown;
+ } else if (m_data.m_value) {
</ins><span class="cx"> m_data.m_value->deref();
</span><ins>+ m_data.m_value = nullptr;
+ }
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> inline const QualifiedName& CSSSelector::tagQName() const
</span></span></pre></div>
<a id="trunkSourceWebCorecssCSSSelectorListcpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/css/CSSSelectorList.cpp (192757 => 192758)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/css/CSSSelectorList.cpp 2015-11-24 02:53:28 UTC (rev 192757)
+++ trunk/Source/WebCore/css/CSSSelectorList.cpp 2015-11-24 03:30:03 UTC (rev 192758)
</span><span class="lines">@@ -111,12 +111,15 @@
</span><span class="cx"> if (!m_selectorArray)
</span><span class="cx"> return;
</span><span class="cx">
</span><del>- for (CSSSelector* s = m_selectorArray; ; ++s) {
</del><ins>+ CSSSelector* selectorArray = m_selectorArray;
+ m_selectorArray = nullptr;
+
+ bool isLastSelector = false;
+ for (CSSSelector* s = selectorArray; !isLastSelector; ++s) {
+ isLastSelector = s->isLastInSelectorList();
</ins><span class="cx"> s->~CSSSelector();
</span><del>- if (s->isLastInSelectorList())
- break;
</del><span class="cx"> }
</span><del>- fastFree(m_selectorArray);
</del><ins>+ fastFree(selectorArray);
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> String CSSSelectorList::selectorsText() const
</span></span></pre>
</div>
</div>
</body>
</html>