CVE-2021-44343: heap-buffer-overflow in ‘/usr/lib/x86_64-linux-gnu/libasan.so.3+0x47dc3’ · Issue #18 · brackeen/ok-file-formats

Version

203defd

Environment

Ubuntu 18.04，64 bit

Testcase

#include <stdio.h> #include <stdlib.h> #include “ok_png.c” #include “ok_png.h”

int main(int _argc, char **_argv) { FILE *file = fopen(_argv[1], “rb”); ok_png image = ok_png_read(file, OK_PNG_COLOR_FORMAT_RGBA ); fclose(file); if (image.data) { printf("Got image! Size: %li x %li\n", (long)image.width, (long)image.height); free(image.data); } return 0; }

Command

Compile test program:

$ gcc -g -o main main.c ok_png.h

Compile test program with address sanitizer with this command:

$ gcc -g -fsanitize=address -o asanpng main.c ok_png.h

Result

The result of running without ASAN:

$ ./main heap-buffer-overflow-6.png
free(): invalid pointer
Aborted (core dumped)

Information obtained by using ASAN:

$ ./asanpng heap-buffer-overflow-6.png
=================================================================
==80024==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60d00000cff1 at pc 0x7fa588189dc4 bp 0x7ffcdbf9eeb0 sp 0x7ffcdbf9e658
WRITE of size 769 at 0x60d00000cff1 thread T0
    #0 0x7fa588189dc3  (/usr/lib/x86_64-linux-gnu/libasan.so.3+0x47dc3)
    #1 0x562d30f5a72f in ok_png_read_data /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:853
    #2 0x562d30f5b15d in ok_png_decode2 /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:971
    #3 0x562d30f5b608 in ok_png_decode /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:1025
    #4 0x562d30f542f3 in ok_png_read_with_allocator /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:188
    #5 0x562d30f541cf in ok_png_read /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:177
    #6 0x562d30f607d7 in main /home/xrz/afl++/ok-file-formats-png/issues/main.c:8
    #7 0x7fa587d72b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #8 0x562d30f53d79 in _start (/home/xrz/afl++/ok-file-formats-png/issues/heap-buffer-overflow-6/asanpng+0x1d79)

0x60d00000cff1 is located 0 bytes to the right of 129-byte region [0x60d00000cf70,0x60d00000cff1)
allocated by thread T0 here:
    #0 0x7fa588208e80 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.3+0xc6e80)
    #1 0x562d30f53e9b in ok_stdlib_alloc /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:58
    #2 0x562d30f59e7c in ok_png_read_data /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:788
    #3 0x562d30f5b15d in ok_png_decode2 /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:971
    #4 0x562d30f5b608 in ok_png_decode /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:1025
    #5 0x562d30f542f3 in ok_png_read_with_allocator /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:188
    #6 0x562d30f541cf in ok_png_read /home/xrz/afl++/ok-file-formats-png/issues/ok_png.c:177
    #7 0x562d30f607d7 in main /home/xrz/afl++/ok-file-formats-png/issues/main.c:8
    #8 0x7fa587d72b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)

SUMMARY: AddressSanitizer: heap-buffer-overflow (/usr/lib/x86_64-linux-gnu/libasan.so.3+0x47dc3) 
Shadow bytes around the buggy address:
  0x0c1a7fff99a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99d0: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c1a7fff99e0: 00 00 00 00 01 fa fa fa fa fa fa fa fa fa 00 00
=>0x0c1a7fff99f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[01]fa
  0x0c1a7fff9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a40: 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
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  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
==80024==ABORTING

Description

A heap-buffer-overflow was discovered in ok_file_formats. The issue is being triggered in ‘/usr/lib/x86_64-linux-gnu/libasan.so.3+0x47dc3’.

Poc

Poc file is this.