Heap Buffer Overflow in plutovg_surface_write_to_png Function

[kittener]

Description

The application crashes due to a heap buffer overflow error when executing the plutovg_surface_write_to_png function. This indicates that the application attempted to write/read past the end of an allocated memory block.

Steps to Reproduce

1. Compile the application.
2. Run the application using the following command: example poc.png

poc3.zip

3. Observe that the application crashes indicating a buffer overflow error.

Expected Behavior

The application should manage memory bounds correctly and not access memory beyond allocated blocks.

Actual Behavior

The application crashes, showing a heap buffer overflow error. Here's the output from AddressSanitizer:

=================================================================
==5909==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f612e1ff704 at pc 0x55f9228352c5 bp 0x7ffc89c47e50 sp 0x7ffc89c47e40
READ of size 4 at 0x7f612e1ff704 thread T0
    #0 0x55f9228352c4 in plutovg_surface_write_to_png (/home/kittener/Documents/plutosvg/build/example/example_asan+0x352c4)
    #1 0x55f92281008b in main (/home/kittener/Documents/plutosvg/build/example/example_asan+0x1008b)
    #2 0x7f6130e00082 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24082)
    #3 0x55f92280ff19 in _start (/home/kittener/Documents/plutosvg/build/example/example_asan+0xff19)

0x7f612e1ff704 is located 0 bytes to the right of 1192173316-byte region [0x7f60e710d800,0x7f612e1ff704)
allocated by thread T0 here:
    #0 0x7f61311fc950 in __interceptor_malloc (/lib/x86_64-linux-gnu/libasan.so.4+0xdf950)
    #1 0x55f922834ba1 in plutovg_surface_create (/home/kittener/Documents/plutosvg/build/example/example_asan+0x34ba1)
    #2 0x55f9228266aa in plutosvg_load_from_memory (/home/kittener/Documents/plutosvg/build/example/example_asan+0x266aa)
    #3 0x55f922826a21 in plutosvg_load_from_file (/home/kittener/Documents/plutosvg/build/example/example_asan+0x26a21)
    #4 0x55f92281005a in main (/home/kittener/Documents/plutosvg/build/example/example_asan+0x1005a)
    #5 0x7f6130e00082 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24082)

SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/kittener/Documents/plutosvg/build/example/example_asan+0x352c4) in plutovg_surface_write_to_png
Shadow bytes around the buggy address:
  0x0feca5c37e90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feca5c37ea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feca5c37eb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feca5c37ec0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feca5c37ed0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0feca5c37ee0:[04]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0feca5c37ef0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0feca5c37f00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0feca5c37f10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0feca5c37f20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0feca5c37f30: 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
==5909==ABORTING

by, kaiyu Xie