Added characters that look like padlocks to URL unescaping blacklist.

net/base/escape.cc

Index: net/base/escape.cc
diff --git a/net/base/escape.cc b/net/base/escape.cc
index 8e6f870fa8b7beca15ab608136148193230892a7..cde972d5f31e0d08f354d5b0c73229a0d50e1e6b 100644
--- a/net/base/escape.cc
+++ b/net/base/escape.cc
@@ -164,6 +164,42 @@ bool HasThreeByteBidiControlCharAtIndex(const STR& escaped_text,
   return third_byte >= 0xA6 && third_byte <= 0xA9;
 }
 
+// Returns true if there is a four-byte banned char at |index|. |first_byte| is
+// the byte at |index|.
+template <typename STR>
+bool HasFourByteBannedCharAtIndex(const STR& escaped_text,
+                                  unsigned char first_byte,
+                                  size_t index) {
+  // The following characters are blacklisted for spoofability concerns.
+  // U+1F50F LOCK WITH INK PEN         (%F0%9F%94%8F)
+  // U+1F510 CLOSED LOCK WITH KEY      (%F0%9F%94%90)
+  // U+1F512 LOCK                      (%F0%9F%94%92)
+  // U+1F513 OPEN LOCK                 (%F0%9F%94%93)
+  if (first_byte != 0xF0)
+    return false;
+
+  unsigned char second_byte;
+  if (!UnescapeUnsignedCharAtIndex(escaped_text, index + 3, &second_byte) ||
+      second_byte != 0x9F) {
+    return false;
+  }
+
+  unsigned char third_byte;
+  if (!UnescapeUnsignedCharAtIndex(escaped_text, index + 6, &third_byte) ||
+      third_byte != 0x94) {
+    return false;
+  }
+
+  unsigned char fourth_byte;
+  if (!UnescapeUnsignedCharAtIndex(escaped_text, index + 9, &fourth_byte) ||
+      (fourth_byte != 0x8F && fourth_byte != 0x90 && fourth_byte != 0x92 &&
+       fourth_byte != 0x93)) {

[Peter Kasting, 2015/06/22 07:35:22]

Nit: Simpler:

  return UnescapeUnsignedCharAtIndex(escaped_text, index + 9, &fourth_byte) &&
      (fourth_byte == 0x8F || fourth_byte == 0x90 || fourth_byte == 0x92 ||
       fourth_byte == 0x93);

[Matt Giuca, 2015/06/23 04:14:10]

Done.

+    return false;
+  }
+
+  return true;
+}
+
 // Unescapes |escaped_text| according to |rules|, returning the resulting
 // string.  Fills in an |adjustments| parameter, if non-NULL, so it reflects
 // the alterations done to the string that are not one-character-to-one-
@@ -217,6 +253,14 @@ STR UnescapeURLWithAdjustmentsImpl(
       // U+2068 FIRST STRONG ISOLATE       (%E2%81%A8)
       // U+2069 POP DIRECTIONAL ISOLATE    (%E2%81%A9)
       //
+      // The following spoofable characters are also banned, because they could
+      // be used to imitate parts of the browser UI.

[mmenke, 2015/06/22 17:05:07]

It's a layering violation for net/ to know about anything in content/ (Which
includes things like the UI thread and IO thread...as well as the fact its
primary use case is being used in a browser).

Also worth noting the network stack is used in apps other than browsers.

[Matt Giuca, 2015/06/23 04:14:10]

OK well the entire reason for these chars being banned is that they clash with
web browser UI, so it doesn't make sense for this comment *not* to mention web
browsers. (ie. if you use this module in a non-web-browser app, then the locks
probably don't need to be banned.)

But I take your point, so I changed "parts of the browser UI" to "parts of a web
browser's UI."

+      //
+      // U+1F50F LOCK WITH INK PEN         (%F0%9F%94%8F)
+      // U+1F510 CLOSED LOCK WITH KEY      (%F0%9F%94%90)
+      // U+1F512 LOCK                      (%F0%9F%94%92)
+      // U+1F513 OPEN LOCK                 (%F0%9F%94%93)
+      //
       // However, some schemes such as data: and file: need to parse the exact
       // binary data when loading the URL. For that reason, CONTROL_CHARS allows
       // unescaping BiDi control characters.
@@ -235,6 +279,12 @@ STR UnescapeURLWithAdjustmentsImpl(
           i += 8;
           continue;
         }
+        if (HasFourByteBannedCharAtIndex(escaped_text, first_byte, i)) {
+          // Keep banned char escaped.
+          result.append(escaped_text, i, 12);
+          i += 11;
+          continue;
+        }
       }
 
       if (first_byte >= 0x80 ||  // Unescape all high-bit characters.