Closed
Description
Description
Whilst experimenting with htmldoc, built from commit 0bef12c, we are able to induce a vulnerability at htmldoc/htmldoc/ps-pdf.cxx:7198 in function parse_table , using a harness compiled from htmldoc/htmldoc.cxx.
Because there is no bounds checking, a heap-based out-of-bound read will be triggered when the software encounters a malformed file, result in information disclosure or denial of service.
Environment
Ubuntu 20.04
gcc 10.3.0 with ASAN
Proof of Concept
The POC is: poc_heap_overflow6
The command is: ./htmldoc --webpage -t pdf -f /dev/null poc_heap_overflow6
The ASAN report is:
=================================================================
==105819==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x621000003910 at pc 0x5555555eec34 bp 0x7fffffff3a60 sp 0x7fffffff3a50
READ of size 8 at 0x621000003910 thread T0
#0 0x5555555eec33 in parse_table /work/htmldoc/htmldoc/ps-pdf.cxx:7198
#1 0x5555555f066a in parse_doc /work/htmldoc/htmldoc/ps-pdf.cxx:4191
#2 0x5555555f63f3 in render_table_row /work/htmldoc/htmldoc/ps-pdf.cxx:5860
#3 0x5555555ee769 in parse_table /work/htmldoc/htmldoc/ps-pdf.cxx:7146
#4 0x5555555f066a in parse_doc /work/htmldoc/htmldoc/ps-pdf.cxx:4191
#5 0x5555555f4f23 in parse_doc /work/htmldoc/htmldoc/ps-pdf.cxx:4537
#6 0x555555604d71 in pspdf_export /work/htmldoc/htmldoc/ps-pdf.cxx:803
#7 0x55555559f764 in main /work/htmldoc/htmldoc/htmldoc.cxx:1291
#8 0x7ffff6b620b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
#9 0x55555559fbcd in _start (/work/htmldoc/htmldoc/htmldoc+0x4bbcd)
0x621000003910 is located 32 bytes to the right of 4080-byte region [0x621000002900,0x6210000038f0)
allocated by thread T0 here:
#0 0x7ffff769bc47 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
#1 0x5555555cf500 in check_pages /work/htmldoc/htmldoc/ps-pdf.cxx:8867
SUMMARY: AddressSanitizer: heap-buffer-overflow /work/htmldoc/htmldoc/ps-pdf.cxx:7198 in parse_table
Shadow bytes around the buggy address:
0x0c427fff86d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c427fff86e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c427fff86f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c427fff8700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c427fff8710: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa fa
=>0x0c427fff8720: fa fa[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c427fff8730: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c427fff8740: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c427fff8750: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c427fff8760: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c427fff8770: 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
==105819==ABORTING
Impact
This vulnerability is capable of inducing information disclosure or denial of service.