Skip to content

heap-buffer-overflow in function ok_png_transform_scanline() at ok_png.c:712:13  #15

Closed
@ConcoctionSec

Description

@ConcoctionSec

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-3.png
free(): invalid pointer
Aborted (core dumped)

Information obtained by using ASAN:

$ ./asanpng heap-buffer-overflow-3.png
==8813==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x621000002680 at pc 0x0000004e48dc bp 0x7ffe51b2f890 sp 0x7ffe51b2f888
WRITE of size 4 at 0x621000002680 thread T0
    #0 0x4e48db in ok_png_transform_scanline /docker/ok-file-formats-png/ok_png.c:712:13
    #1 0x4e48db in ok_png_read_data /docker/ok-file-formats-png/ok_png.c:895:13
    #2 0x4e48db in ok_png_decode2 /docker/ok-file-formats-png/ok_png.c:971:23
    #3 0x4e48db in ok_png_decode /docker/ok-file-formats-png/ok_png.c:1025:5
    #4 0x4e81d5 in ok_png_read_with_allocator /docker/ok-file-formats-png/ok_png.c:188:9
    #5 0x4e81d5 in ok_png_read /docker/ok-file-formats-png/ok_png.c:177:12
    #6 0x4e81d5 in main /docker/ok-file-formats-png/main.c:8:20
    #7 0x7fe87e6f50b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #8 0x41c38d in _start (/docker/ok-file-formats-png/afl_asan+0x41c38d)

0x621000002680 is located 384 bytes to the right of 4096-byte region [0x621000001500,0x621000002500)
allocated by thread T0 here:
    #0 0x4975ed in malloc (/docker/ok-file-formats-png/afl_asan+0x4975ed)
    #1 0x4cd004 in ok_png_read_data /docker/ok-file-formats-png/ok_png.c:774:29
    #2 0x4cd004 in ok_png_decode2 /docker/ok-file-formats-png/ok_png.c:971:23
    #3 0x4cd004 in ok_png_decode /docker/ok-file-formats-png/ok_png.c:1025:5
    #4 0x4e81d5 in ok_png_read_with_allocator /docker/ok-file-formats-png/ok_png.c:188:9
    #5 0x4e81d5 in ok_png_read /docker/ok-file-formats-png/ok_png.c:177:12
    #6 0x4e81d5 in main /docker/ok-file-formats-png/main.c:8:20
    #7 0x7fe87e6f50b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)

SUMMARY: AddressSanitizer: heap-buffer-overflow /docker/ok-file-formats-png/ok_png.c:712:13 in ok_png_transform_scanline
Shadow bytes around the buggy address:
  0x0c427fff8480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fff8490: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fff84a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c427fff84d0:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff84e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff84f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff8500: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff8510: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff8520: 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
  Shadow gap:              cc
==8813==ABORTING

Description

A heap-buffer-overflow was discovered in ok_file_formats. The issue is being triggered in function ok_png_transform_scanline() at ok_png.c:712:13.

Poc

Poc file is this.

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions