Project: faad2 (knik0/faad2), language: c++
Vulnerability instance: faad2.cve-2018-20199
Sanitizer: address

================= Bug Report (1/1) ==================
## Source: GitHub Issue
## URL: https://github.com/knik0/faad2/issues/24
## Description:
Issue: knik0/faad2#24
Title: Null pointer dereference vulnerability in ifilter_bank(libfaad/filtbank.c:223)
State: closed
Created by: fantasy7082
Created at: 2018-12-17 06:22:35+00:00

Issue Body:
Hi, i found a null pointer dereference bug in Freeware Advanced Audio Decoder 2 (FAAD2) 2.8.8. It crashed in function ifilter_bank.the details are below(ASAN):


```
./faad faad_res/004-null-point-filtbank_223 -o out.wav
 *********** Ahead Software MPEG-4 AAC Decoder V2.8.8 ******************

 Build: Dec 13 2018
 Copyright 2002-2004: Ahead Software AG
 http://www.audiocoding.com
 bug tracking: https://sourceforge.net/p/faac/bugs/
 Floating point version

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License.

 **************************************************************************

faad_res/004-null-point-filtbank_223 file info:
ADTS, 0.043 sec, 37 kbps, 48000 Hz

  ---------------------
 | Config: 43 Ch       |
  ---------------------
 | Ch |    Position    |
  ---------------------
 | 00 | Left front     |
 | 01 | Right front    |
 | 02 | Unknown        |
 | 03 | Unknown        |
 | 04 | Unknown        |
 | 05 | Unknown        |
 | 06 | Unknown        |
 | 07 | Unknown        |
 | 08 | Unknown        |
 | 09 | Unknown        |
 | 10 | Unknown        |
 | 11 | Unknown        |
 | 12 | Unknown        |
 | 13 | Unknown        |
 | 14 | Unknown        |
 | 15 | Unknown        |
 | 16 | Unknown        |
 | 17 | Unknown        |
 | 18 | Unknown        |
 | 19 | Unknown        |
 | 20 | Unknown        |
 | 21 | Unknown        |
 | 22 | Unknown        |
 | 23 | Unknown        |
 | 24 | Unknown        |
 | 25 | Unknown        |
 | 26 | Unknown        |
 | 27 | Unknown        |
 | 28 | Unknown        |
 | 29 | Unknown        |
 | 30 | Unknown        |
 | 31 | Unknown        |
 | 32 | Unknown        |
 | 33 | Unknown        |
 | 34 | Unknown        |
 | 35 | Unknown        |
 | 36 | Unknown        |
 | 37 | Unknown        |
 | 38 | Unknown        |
 | 39 | Unknown        |
 | 40 | Unknown        |
 | 41 | Unknown        |
 | 42 | Unknown        |
  ---------------------

ASAN:SIGSEGVfaad_res/004-null-point-filtbank_223.
=================================================================
==7068==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f82e567eeeb bp 0x7ffe62c6dc40 sp 0x7ffe62c6bb50 T0)
    #0 0x7f82e567eeea in ifilter_bank /root/faad2_asan/libfaad/filtbank.c:223
    #1 0x7f82e56b7d3e in reconstruct_single_channel /root/faad2_asan/libfaad/specrec.c:1014
    #2 0x7f82e56c0e28 in single_lfe_channel_element /root/faad2_asan/libfaad/syntax.c:631
    #3 0x7f82e56bf354 in decode_sce_lfe /root/faad2_asan/libfaad/syntax.c:351
    #4 0x7f82e56c02da in raw_data_block /root/faad2_asan/libfaad/syntax.c:441
    #5 0x7f82e567a9c3 in aac_frame_decode /root/faad2_asan/libfaad/decoder.c:990
    #6 0x7f82e567a566 in NeAACDecDecode /root/faad2_asan/libfaad/decoder.c:821
    #7 0x40f8ae in decodeAACfile /root/faad2_asan/frontend/main.c:679
    #8 0x411dd4 in faad_main /root/faad2_asan/frontend/main.c:1323
    #9 0x411fe5 in main /root/faad2_asan/frontend/main.c:1366
    #10 0x7f82e52b282f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #11 0x401aa8 in _start (/usr/local/faad-asan/bin/faad+0x401aa8)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /root/faad2_asan/libfaad/filtbank.c:223 ifilter_bank
==7068==ABORTING
```

POC FILE:https://github.com/fantasy7082/image_test/blob/master/004-null-point-filtbank_223


Comments:
Comment by hlef on 2019-08-18 15:09:35+00:00:
Reproducible on the latest master.

This is roughly the same issue as https://github.com/knik0/faad2/issues/32. Applying my patch suggestion fixes this issue as well.

@fabiangreffrath I will PR it once the current batch of security fixes has been reviewed/merged.

---

Comment by hlef on 2019-08-18 15:10:29+00:00:
For the record, this was assigned CVE-2018-20199.

Build script:
#!/bin/bash -eu
# Minimized build script with only core build commands
set -eu
./bootstrap
./configure
make -j$(nproc)

Dockerfile:
FROM hwiwonlee/secb.base:latest
RUN apt-get update && apt-get install -y make autoconf automake libtool
RUN git clone https://github.com/knik0/faad2 faad2
RUN git -C faad2 checkout b20a5d2a6fab63219981bdb29de74bf280f14451
WORKDIR $SRC/faad2
COPY build.sh $SRC/

Additional files: