stack-overflow in mjs_op_json_stringify() at mjs.c:11362

[vorfreuder]

The name of an affected Product mjs

The affected version Commit: b1b6eac (Tag: 2.20.0)

Description An issue in cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_op_json_stringify function in the mjs.c file.

Vulnerability Type Out-of-bounds Write

Environment

• Operating System

  Distributor ID: Ubuntu
  Description:    Ubuntu 18.04.6 LTS
  Release:        18.04
  Codename:       bionic

• Compiler

  Ubuntu clang version 12.0.1-++20211102090516+fed41342a82f-1~exp1~20211102211019.11
  Target: x86_64-pc-linux-gnu
  Thread model: posix

Steps to Reproduce download poc.zip, then

git clone https://github.com/cesanta/mjs
cd mjs
git checkout b1b6eac
clang -ggdb -O0 -DMJS_MAIN mjs.c -o mjs -ldl
unzip poc.zip
# run command
./mjs -f poc

ASAN Info

AddressSanitizer:DEADLYSIGNAL
=================================================================
==141==ERROR: AddressSanitizer: stack-overflow on address 0x0000c40cc508 (pc 0x0000004ec73d bp 0x7fffc40cc510 sp 0x0000c40cc508 T0)
    #0 0x4ec73d in mjs_op_json_stringify /mjs/mjs.c:11362:1
    #1 0x4ef755 in mjs_exec_internal /mjs/mjs.c:9044:5
    #2 0x4efa40 in mjs_exec_file /mjs/mjs.c:9067:11
    #3 0x4f75b9 in main /mjs/mjs.c:11406:13
    #4 0x7fbe53915c86 in __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:310
    #5 0x41b7f9 in _start (/mjs/mjs+0x41b7f9)

SUMMARY: AddressSanitizer: stack-overflow /mjs/mjs.c:11362:1 in mjs_op_json_stringify
==141==ABORTING