Issue 1182: Fix fuzzing bug (open-source-parsers#1183)

This patch fixes a fuzzing bug by resolving a bad fallthrough in the setComment logic. The result is that we get a proper error instead of an assert, making the library friendlier to use and less likely to cause issue for consumers. See related Chromium project bug: https://bugs.chromium.org/p/chromium/issues/detail?id=989851 Issue: 1182
Jesonchang12 · May 31, 2020 · 9be5895 · 9be5895
1 parent 6aba23f
commit 9be5895
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diff --git a/src/lib_json/json_reader.cpp b/src/lib_json/json_reader.cpp
@@ -1175,8 +1175,11 @@ bool OurReader::readToken(Token& token) {
     if (features_.allowSingleQuotes_) {
       token.type_ = tokenString;
       ok = readStringSingleQuote();
-      break;
-    } // else fall through
+    } else {
+      // If we don't allow single quotes, this is a failure case.
+      ok = false;
+    }
+    break;
   case '/':
     token.type_ = tokenComment;
     ok = readComment();

diff --git a/test/data/fail_invalid_quote.json b/test/data/fail_invalid_quote.json
@@ -0,0 +1 @@
+{'//this is bad JSON.'}