Stack-overflow (OSS-Fuzz 1444)

[nlohmann]

Detailed report: https://oss-fuzz.com/testcase?key=6168426957504512

Project: json
Fuzzer: libFuzzer_json_parse_afl_fuzzer
Job Type: libfuzzer_asan_json
Platform Id: linux

Crash Type: Stack-overflow
Crash Address: 0x7ffd2de7bd88
Crash State:
  nlohmann::basic_json<std::__1::map, std::__1::vector, std::__1::basic_string<cha
  
Sanitizer: address (ASAN)

Regressed: https://oss-fuzz.com/revisions?job=libfuzzer_asan_json&range=201705051619:201705061619

Reproducer Testcase: https://oss-fuzz.com/download?testcase_id=6168426957504512


Issue filed automatically.

See https://github.com/google/oss-fuzz/blob/master/docs/reproducing.md for more information.

This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without an upstream patch, then the bug report will automatically
become visible to the public.

clusterfuzz-testcase-minimized-6168426957504512.zip

[nlohmann]

This is a classic stack overflow, related to #517. It reads an array with excessive nesting.

[nlohmann]

There is currently little we can do about this error. One solution could be rewriting the parser to a non-recursive one.

[nlohmann]

For some strange reason, OSS-Fuzz reported this issue as fixed.