Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Another Heap OOB in json_parse_object() #97

Closed
hyrathon opened this issue Nov 14, 2022 · 0 comments · Fixed by #98
Closed

Another Heap OOB in json_parse_object() #97

hyrathon opened this issue Nov 14, 2022 · 0 comments · Fixed by #98

Comments

@hyrathon
Copy link

Another Heap OOB in json_parse_object()

In json_parse_object(), there is a heap out-of-bound write. The bug can be triggered with an invocation of json_parse_ex() with specific flags combination. The root cause of this vulnerability is that the parameter object transferred to json_parse_obect() is not properly sanitized, and it is pointed to out-of-bound position assigned by upper layer function.

Here is the output of Google ASAN when the vulnerability is triggerred:

The flags is 0x5fd6d7d6d6247bdf
=================================================================
==5354==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61a000000550 at pc 0x557f8e3323e7 bp 0x7ffd29216ab0 sp 0x7ffd29216aa8
WRITE of size 8 at 0x61a000000550 thread T0
    #0 0x557f8e3323e6 in json_parse_object /home/hyrathon/Desktop/jsonh/./json.h:1670:21
    #1 0x557f8e334ad9 in json_parse_value /home/hyrathon/Desktop/jsonh/./json.h:1955:7
    #2 0x557f8e3338f0 in json_parse_object /home/hyrathon/Desktop/jsonh/./json.h:1719:5
    #3 0x557f8e334ad9 in json_parse_value /home/hyrathon/Desktop/jsonh/./json.h:1955:7
    #4 0x557f8e3338f0 in json_parse_object /home/hyrathon/Desktop/jsonh/./json.h:1719:5
    #5 0x557f8e334ad9 in json_parse_value /home/hyrathon/Desktop/jsonh/./json.h:1955:7
    #6 0x557f8e338d4b in json_parse_array /home/hyrathon/Desktop/jsonh/./json.h:1809:5
    #7 0x557f8e334ed5 in json_parse_value /home/hyrathon/Desktop/jsonh/./json.h:1962:7
    #8 0x557f8e3338f0 in json_parse_object /home/hyrathon/Desktop/jsonh/./json.h:1719:5
    #9 0x557f8e3341c8 in json_parse_value /home/hyrathon/Desktop/jsonh/./json.h:1940:5
    #10 0x557f8e33cc85 in json_parse_ex /home/hyrathon/Desktop/jsonh/./json.h:2129:3
    #11 0x557f8e353192 in main /home/hyrathon/Desktop/jsonh/fuzz.c:29:5
    #12 0x7fae53ff9d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #13 0x7fae53ff9e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #14 0x557f8e261314 in _start (/home/hyrathon/Desktop/jsonh/san+0x33314) (BuildId: a0e983e1c9c38a8763824dc5481f79d22fe8c82a)

0x61a000000550 is located 0 bytes to the right of 1232-byte region [0x61a000000080,0x61a000000550)
allocated by thread T0 here:
    #0 0x557f8e2e415e in __interceptor_malloc (/home/hyrathon/Desktop/jsonh/san+0xb615e) (BuildId: a0e983e1c9c38a8763824dc5481f79d22fe8c82a)
    #1 0x557f8e33bf15 in json_parse_ex /home/hyrathon/Desktop/jsonh/./json.h:2088:18
    #2 0x557f8e353192 in main /home/hyrathon/Desktop/jsonh/fuzz.c:29:5
    #3 0x7fae53ff9d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/hyrathon/Desktop/jsonh/./json.h:1670:21 in json_parse_object
Shadow bytes around the buggy address:
  0x0c347fff8050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c347fff80a0: 00 00 00 00 00 00 00 00 00 00[fa]fa fa fa fa fa
  0x0c347fff80b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff80c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff80d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff80e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff80f0: 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
==5354==ABORTING

The input to trigger this bug is attached. The first 8 bytes are the flags for json_parse_ex() and the rest is the content(src). Please use address sanitizer to reproduce the bug, as non-crash overflow is hard to detect or locate without shadow memory.

Version: latest commit (bdcf2e1)
crash-input.zip

sheredom added a commit that referenced this issue Nov 14, 2022
The issue was caused by "NaNE1" - EG. I was accidentally accepting the 'E' as being valid after a NaN was processed, which it wasn't.

Fixes #92.
Fixes #93.
Fixes #94.
Fixes #95.
Fixes #96.
Fixes #97.
sheredom added a commit that referenced this issue Nov 14, 2022
The issue was caused by "NaNE1" - EG. I was accidentally accepting the 'E' as being valid after a NaN was processed, which it wasn't.

Fixes #92.
Fixes #93.
Fixes #94.
Fixes #95.
Fixes #96.
Fixes #97.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging a pull request may close this issue.

1 participant