From 7ae095fa091af9a94e0e9bf140280a0519859d98 Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sun, 4 Feb 2024 17:27:43 -0500
Subject: [PATCH] Fix JSON parser error found by fuzz

---
 .../f297bc5680b3730d3386caa8dee36bf5a853516b                   | 1 +
 fuzz/qtest/fuzz.test                                           | 2 +-
 libqpdf/JSON.cc                                                | 3 ++-
 3 files changed, 4 insertions(+), 2 deletions(-)
 create mode 100644 fuzz/json_fuzzer_seed_corpus/f297bc5680b3730d3386caa8dee36bf5a853516b

diff --git a/fuzz/json_fuzzer_seed_corpus/f297bc5680b3730d3386caa8dee36bf5a853516b b/fuzz/json_fuzzer_seed_corpus/f297bc5680b3730d3386caa8dee36bf5a853516b
new file mode 100644
index 00000000..6c533a40
--- /dev/null
+++ b/fuzz/json_fuzzer_seed_corpus/f297bc5680b3730d3386caa8dee36bf5a853516b
@@ -0,0 +1 @@
+"\,,,,,p,,-\,,,,
\ No newline at end of file
diff --git a/fuzz/qtest/fuzz.test b/fuzz/qtest/fuzz.test
index db1efbc1..4a20e5bf 100644
--- a/fuzz/qtest/fuzz.test
+++ b/fuzz/qtest/fuzz.test
@@ -16,7 +16,7 @@ my @fuzzers = (
     ['dct' => 1],
     ['flate' => 1],
     ['hex' => 1],
-    ['json' => 37],
+    ['json' => 38],
     ['lzw' => 2],
     ['pngpredictor' => 1],
     ['runlength' => 6],
diff --git a/libqpdf/JSON.cc b/libqpdf/JSON.cc
index c9816809..28f451a9 100644
--- a/libqpdf/JSON.cc
+++ b/libqpdf/JSON.cc
@@ -1246,7 +1246,8 @@ JSONParser::handleToken()
         break;
 
     default:
-        throw std::logic_error("JSONParser::handleToken : non-terminal lexer state encountered");
+        throw std::runtime_error(
+            "JSON: offset " + std::to_string(offset) + ": premature end of input");
         break;
     }