Add bounds check to StringImpl::operator[]

https://bugs.webkit.org/show_bug.cgi?id=263899 Reviewed by Ryosuke Niwa. Add bounds check to StringImpl::operator[] for extra safety. This tested as performance neutral on Speedometer and Jetstream. * Source/WTF/wtf/text/StringImpl.h: (WTF::StringImpl::at const): * Source/WTF/wtf/text/WTFString.h: (WTF::String::characterAt const): Canonical link: https://commits.webkit.org/269967@main
WebKit · Oct 30, 2023 · e93f8aa · e93f8aa
1 parent 135c6d5
commit e93f8aa
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/Source/WTF/wtf/text/StringImpl.h b/Source/WTF/wtf/text/StringImpl.h
@@ -1165,7 +1165,7 @@ inline void StringImpl::deref()
 
 inline UChar StringImpl::at(unsigned i) const
 {
-    ASSERT_WITH_SECURITY_IMPLICATION(i < m_length);
+    RELEASE_ASSERT(i < m_length);
     return is8Bit() ? m_data8[i] : m_data16[i];
 }
 

diff --git a/Source/WTF/wtf/text/WTFString.h b/Source/WTF/wtf/text/WTFString.h
@@ -446,7 +446,7 @@ inline UChar String::characterAt(unsigned index) const
 {
     if (!m_impl || index >= m_impl->length())
         return 0;
-    return (*m_impl)[index];
+    return m_impl->is8Bit() ? m_impl->characters8()[index] : m_impl->characters16()[index];
 }
 
 inline String WARN_UNUSED_RETURN makeStringByReplacingAll(const String& string, UChar target, UChar replacement)