AddressSanitizer: heap-buffer-overflow in pspdf_prepare_outpages() in ps-pdf.cxx:1338:15

[chibataiki]

Hello, While fuzzing htmldoc , I found a heap-buffer-overflow in the pspdf_prepare_outpages() ,in ps-pdf.cxx:1338:15

test platform
htmldoc Version 1.9.12 git [master 6898d0a]
OS :Ubuntu 20.04.1 LTS x86_64
kernel: 5.4.0-53-generic
compiler: clang version 10.0.0-4ubuntu1
reproduced:

htmldoc -f demo.pdf   poc2.html

poc(zipped for update):
poc2.zip

=================================================================
==38089==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6150003b19f8 at pc 0x000000555985 bp 0x7ffca8f71990 sp 0x7ffca8f71988
WRITE of size 4 at 0x6150003b19f8 thread T0
    #0 0x555984 in pspdf_prepare_outpages() /home//htmldoc_sani/htmldoc/ps-pdf.cxx:1338:15
    #1 0x555984 in pspdf_export /home//htmldoc_sani/htmldoc/ps-pdf.cxx:901
    #2 0x53c845 in main /home//htmldoc_sani/htmldoc/htmldoc.cxx:1291:3
    #3 0x7f44ac7c40b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
    #4 0x41f8bd in _start (/home//htmldoc_sani/htmldoc/htmldoc+0x41f8bd)

0x6150003b19f8 is located 0 bytes to the right of 504-byte region [0x6150003b1800,0x6150003b19f8)
allocated by thread T0 here:
    #0 0x4ee5df in __interceptor_malloc /home/goushi/work/libfuzzer-workshop/src/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:146
    #1 0x5500bf in pspdf_prepare_outpages() /home//htmldoc_sani/htmldoc/ps-pdf.cxx:1258:27
    #2 0x5500bf in pspdf_export /home//htmldoc_sani/htmldoc/ps-pdf.cxx:901
    #3 0x53c845 in main /home//htmldoc_sani/htmldoc/htmldoc.cxx:1291:3
    #4 0x7f44ac7c40b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home//htmldoc_sani/htmldoc/ps-pdf.cxx:1338:15 in pspdf_prepare_outpages()
Shadow bytes around the buggy address:
  0x0c2a8006e2e0: fd fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa
  0x0c2a8006e2f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c2a8006e300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2a8006e310: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c2a8006e320: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c2a8006e330: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00[fa]
  0x0c2a8006e340: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c2a8006e350: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c2a8006e360: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c2a8006e370: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c2a8006e380: 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
==38089==ABORTING

reporter: chiba of topsec alphalab

[michaelrsweet]

Confirmed, investigating...

[michaelrsweet]

[master 6e8a955] Fix a number-up crash bug (Issue #413)

[chibataiki]

CVE-2021-23165 assigned