Ignore unknown options to subresource integrity

Source/core/frame/SubresourceIntegrity.cpp

Index: Source/core/frame/SubresourceIntegrity.cpp
diff --git a/Source/core/frame/SubresourceIntegrity.cpp b/Source/core/frame/SubresourceIntegrity.cpp
index 0832fccf0233a8642aa933f89679ab5b4ef65fde..a911b1fe6f5de2b48b4d2083c8ae45d902f341da 100644
--- a/Source/core/frame/SubresourceIntegrity.cpp
+++ b/Source/core/frame/SubresourceIntegrity.cpp
@@ -40,6 +40,16 @@ static bool isTypeCharacter(UChar c)
     return isASCIIAlphanumeric(c) || c == '+' || c == '.' || c == '-';
 }
 
+static bool isOptionNameCharacter(UChar c)
+{
+    return isASCIIAlphanumeric(c) || c == '-';
+}
+
+static bool isOptionValueCharacter(UChar c)
+{
+    return isASCIIAlphanumeric(c) || c == '!' || c == '#' || c == '$' || c == '%' || c == '&' || c == '\'' || c == '*' || c == '+' || c == '-'  || c == '.' || c == '^' || c == '_' || c == '`' || c == '|' || c == '~' || c == '/';
+}
+
 static void logErrorToConsole(const String& message, Document& document)
 {
     document.addConsoleMessage(ConsoleMessage::create(SecurityMessageSource, ErrorMessageLevel, message));
@@ -203,45 +213,69 @@ bool SubresourceIntegrity::parseDigest(const UChar*& position, const UChar* end,
     return true;
 }
 
+bool SubresourceIntegrity::isValidMimeTypeValue(const String& value)
+{
+    Vector<UChar> characters;
+    value.appendTo(characters);
+    const UChar* position = characters.data();
+    const UChar* end = characters.end();
+
+    skipWhile<UChar, isASCIIAlpha>(position, end);
+    if (position == end)
+        return false;
+
+    if (!skipExactly<UChar>(position, end, '/'))
+        return false;
+
+    skipWhile<UChar, isTypeCharacter>(position, end);
+    if (position != end)
+        return false;
+
+    return true;
+}
+
 
 // Before:
 //
-// [algorithm]-[hash]     OR      [algorithm]-[hash]?[options]
-//                   ^                              ^         ^
-//        position/end                       position       end
+// [algorithm]-[hash]     OR      [algorithm]-[hash]?[name]=[value]     OR      [algorithm]-[hash]?[name]=[value]?[rest of options]
+//                   ^                              ^              ^                              ^                                ^
+//        position/end                       position            end                       position                              end
 //
 // After (if successful: if the method returns false, we make no promises and the caller should exit early):
 //
-// [algorithm]-[hash]     OR      [algorithm]-[hash]?[options]
-//                   ^                                        ^
-//        position/end                             position/end
-bool SubresourceIntegrity::parseMimeType(const UChar*& position, const UChar* end, String& type)
+// [algorithm]-[hash]     OR      [algorithm]-[hash]?[name]=[value]     OR      [algorithm]-[hash]?[name]=[value]?[rest of options]

[Mike West, 2015/05/11 03:25:28]

This is such a weird syntax.

+//                   ^                                             ^                                            ^                  ^
+//        position/end                                  position/end                                     position                end
+bool SubresourceIntegrity::parseOption(const UChar*& position, const UChar* end, String& name, String& value)
 {
-    type = emptyString();
+    name = emptyString();
+    value = emptyString();
 
     if (position == end)
         return true;
 
-    if (!skipToken<UChar>(position, end, "?ct="))
+    if (!skipExactly<UChar>(position, end, '?'))
         return false;
 
     const UChar* begin = position;
-    skipWhile<UChar, isASCIIAlpha>(position, end);
+    skipWhile<UChar, isOptionNameCharacter>(position, end);
     if (position == end)
         return false;
 
-    if (!skipExactly<UChar>(position, end, '/'))
-        return false;
+    name = String(begin, position - begin);
 
-    if (position == end)
+    if (!skipExactly<UChar>(position, end, '=') || position == end)
         return false;
 
-    skipWhile<UChar, isTypeCharacter>(position, end);
-    if (position != end)
-        return false;
+    begin = position;
+    skipWhile<UChar, isOptionValueCharacter>(position, end);
 
-    type = String(begin, position - begin);
-    return true;
+    value = String(begin, position - begin);
+
+    if (position == end || *position == '?')

[Mike West, 2015/05/11 03:25:28]

Would you mind asserting that `position < end` before dereferencing it?

+        return true;
+
+    return false;
 }
 
 SubresourceIntegrity::IntegrityParseResult SubresourceIntegrity::parseIntegrityAttribute(const WTF::String& attribute, WTF::Vector<IntegrityMetadata>& metadataList, Document& document)
@@ -300,14 +334,37 @@ SubresourceIntegrity::IntegrityParseResult SubresourceIntegrity::parseIntegrityA
             continue;
         }
 
-        if (!parseMimeType(position, currentIntegrityEnd, type)) {
-            logErrorToConsole("Error parsing 'integrity' attribute ('" + attribute + "'). The content type could not be parsed.", document);
-            error = true;
-            skipUntil<UChar, isASCIISpace>(position, end);
-            UseCounter::count(document, UseCounter::SRIElementWithUnparsableIntegrityAttribute);
-            continue;
+        bool skipToNextIntegrity = false;
+        while (*position == '?') {
+            String name, value;
+            if (!parseOption(position, currentIntegrityEnd, name, value)) {
+                logErrorToConsole("Error parsing 'integrity' attribute ('" + attribute + "'). The options could not be parsed.", document);
+                skipToNextIntegrity = true;
+                error = true;
+                skipUntil<UChar, isASCIISpace>(position, end);
+                UseCounter::count(document, UseCounter::SRIElementWithUnparsableIntegrityAttribute);
+                break;
+            }
+
+            if (name == "ct") {
+                if (!isValidMimeTypeValue(value)) {
+                    logErrorToConsole("Error parsing 'integrity' attribute ('" + attribute + "'). The content type could not be parsed.", document);
+                    skipToNextIntegrity = true;
+                    error = true;
+                    skipUntil<UChar, isASCIISpace>(position, end);
+                    UseCounter::count(document, UseCounter::SRIElementWithUnparsableIntegrityAttribute);
+                    break;
+                }
+
+                type = value;
+            } else {
+                logErrorToConsole("Ignoring unrecogized 'integrity' attribute option '" + name + "' with value '" + value + "'.", document);
+            }
         }
 
+        if (skipToNextIntegrity)
+            continue;
+
         IntegrityMetadata integrityMetadata = {
             digest,
             algorithm,