WindowBase64::atob() does not remove space characters from input

Source/wtf/text/Base64.cpp

Index: Source/wtf/text/Base64.cpp
diff --git a/Source/wtf/text/Base64.cpp b/Source/wtf/text/Base64.cpp
index 21552ffbe0cf1bec0131a1f4e9db0d6cdf6e89df..8aa34e257e81a433d8761f9843eba761db90fd63 100644
--- a/Source/wtf/text/Base64.cpp
+++ b/Source/wtf/text/Base64.cpp
@@ -128,7 +128,7 @@ void base64Encode(const char* data, unsigned len, Vector<char>& out, Base64Encod
     }
 }
 
-bool base64Decode(const Vector<char>& in, Vector<char>& out, Base64DecodePolicy policy)
+bool base64Decode(const Vector<char>& in, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 {
     out.clear();
 
@@ -136,11 +136,11 @@ bool base64Decode(const Vector<char>& in, Vector<char>& out, Base64DecodePolicy
     if (in.size() > UINT_MAX)
         return false;
 
-    return base64Decode(in.data(), in.size(), out, policy);
+    return base64Decode(in.data(), in.size(), out, shouldIgnoreCharacter, policy);
 }
 
 template<typename T>
-static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<char>& out, Base64DecodePolicy policy)
+static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 {
     out.clear();
     if (!length)
@@ -154,16 +154,14 @@ static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<c
         unsigned ch = data[idx];
         if (ch == '=') {
             ++equalsSignCount;
-            // There should be no padding if length is a multiple of 4, and there
-            // should never be more than 2 padding characters.
-            if (policy == Base64FailOnInvalidCharacterOrExcessPadding && (length % 4 || equalsSignCount > 2))
+            // There should never be more than 2 padding characters.
+            if (policy == Base64ValidatePadding && equalsSignCount > 2)
                 return false;
         } else if (('0' <= ch && ch <= '9') || ('A' <= ch && ch <= 'Z') || ('a' <= ch && ch <= 'z') || ch == '+' || ch == '/') {
             if (equalsSignCount)
                 return false;
-            out[outLength] = base64DecMap[ch];
-            ++outLength;
-        } else if (policy == Base64FailOnInvalidCharacterOrExcessPadding || policy == Base64FailOnInvalidCharacter || (policy == Base64IgnoreWhitespace && !isSpaceOrNewline(ch))) {
+            out[outLength++] = base64DecMap[ch];
+        } else if (!shouldIgnoreCharacter || !shouldIgnoreCharacter(ch)) {
             return false;
         }
     }
@@ -171,6 +169,11 @@ static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<c
     if (!outLength)
         return !equalsSignCount;
 
+    // There should be no padding if length is a multiple of 4.
+    // We use (outLength + equalsSignCount) instead of length because we don't want to account for ignored characters.
+    if (policy == Base64ValidatePadding && equalsSignCount && (outLength + equalsSignCount) % 4)
+        return false;
+
     // Valid data is (n * 4 + [0,2,3]) characters long.
     if ((outLength % 4) == 1)
         return false;
@@ -204,23 +207,23 @@ static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<c
     return true;
 }
 
-bool base64Decode(const char* data, unsigned length, Vector<char>& out, Base64DecodePolicy policy)
+bool base64Decode(const char* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 {
-    return base64DecodeInternal<LChar>(reinterpret_cast<const LChar*>(data), length, out, policy);
+    return base64DecodeInternal<LChar>(reinterpret_cast<const LChar*>(data), length, out, shouldIgnoreCharacter, policy);
 }
 
-bool base64Decode(const UChar* data, unsigned length, Vector<char>& out, Base64DecodePolicy policy)
+bool base64Decode(const UChar* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 {
-    return base64DecodeInternal<UChar>(data, length, out, policy);
+    return base64DecodeInternal<UChar>(data, length, out, shouldIgnoreCharacter, policy);
 }
 
-bool base64Decode(const String& in, Vector<char>& out, Base64DecodePolicy policy)
+bool base64Decode(const String& in, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 {
     if (in.isEmpty())
-        return base64DecodeInternal<LChar>(0, 0, out, policy);
+        return base64DecodeInternal<LChar>(0, 0, out, shouldIgnoreCharacter, policy);
     if (in.is8Bit())
-        return base64DecodeInternal<LChar>(in.characters8(), in.length(), out, policy);
-    return base64DecodeInternal<UChar>(in.characters16(), in.length(), out, policy);
+        return base64DecodeInternal<LChar>(in.characters8(), in.length(), out, shouldIgnoreCharacter, policy);
+    return base64DecodeInternal<UChar>(in.characters16(), in.length(), out, shouldIgnoreCharacter, policy);
 }
 
 } // namespace WTF