Stack-use-after-scope in sao.cc: void apply_sao_internal<unsigned short>

[fdu-sec]

Description

Stack-use-after-scope (/libde265/libde265/build/libde265/liblibde265.so+0x19337f) in void apply_sao_internal(de265_image*, int, int, slice_segment_header const*, int, int, int, unsigned short const*, int, unsigned short*, int)

Version

$ ./dec265 -h
 dec265  v1.0.8
--------------
usage: dec265 [options] videofile.bin
The video file must be a raw bitstream, or a stream with NAL units (option -n).

options:
  -q, --quiet       do not show decoded image
  -t, --threads N   set number of worker threads (0 - no threading)
  -c, --check-hash  perform hash check
  -n, --nal         input is a stream with 4-byte length prefixed NAL units
  -f, --frames N    set number of frames to process
  -o, --output      write YUV reconstruction
  -d, --dump        dump headers
  -0, --noaccel     do not use any accelerated code (SSE)
  -v, --verbose     increase verbosity level (up to 3 times)
  -L, --no-logging  disable logging
  -B, --write-bytestream FILENAME  write raw bytestream (from NAL input)
  -m, --measure YUV compute PSNRs relative to reference YUV
  -T, --highest-TID select highest temporal sublayer to decode
      --disable-deblocking   disable deblocking filter
      --disable-sao          disable sample-adaptive offset filter
  -h, --help        show help

Replay

git clone https://github.com/strukturag/libde265.git
cd libde265
mkdir build
cd build
cmake ../ -DCMAKE_CXX_FLAGS="-fsanitize=address"
make -j$(nproc)
./dec265/dec265 poc19

ASAN

WARNING: end_of_sub_stream_one_bit not set to 1 when it should be
WARNING: non-existing PPS referenced
WARNING: CTB outside of image area (concealing stream error...)
=================================================================
==50847==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffc2aa1734c at pc 0x7f8a42e42380 bp 0x7ffc2aa14530 sp 0x7ffc2aa14520
READ of size 4 at 0x7ffc2aa1734c thread T0
    #0 0x7f8a42e4237f in void apply_sao_internal<unsigned short>(de265_image*, int, int, slice_segment_header const*, int, int, int, unsigned short const*, int, unsigned short*, int) (/libde265/libde265/build/libde265/liblibde265.so+0x19337f)
    #1 0x7f8a42e403b6 in void apply_sao<unsigned char>(de265_image*, int, int, slice_segment_header const*, int, int, int, unsigned char const*, int, unsigned char*, int) (/libde265/libde265/build/libde265/liblibde265.so+0x1913b6)
    #2 0x7f8a42e3e909 in apply_sample_adaptive_offset_sequential(de265_image*) (/libde265/libde265/build/libde265/liblibde265.so+0x18f909)
    #3 0x7f8a42dcca5d in decoder_context::run_postprocessing_filters_sequential(de265_image*) (/libde265/libde265/build/libde265/liblibde265.so+0x11da5d)
    #4 0x7f8a42dc3ecf in decoder_context::decode_some(bool*) (/libde265/libde265/build/libde265/liblibde265.so+0x114ecf)
    #5 0x7f8a42dc6ba8 in decoder_context::decode(int*) (/libde265/libde265/build/libde265/liblibde265.so+0x117ba8)
    #6 0x7f8a42dade95 in de265_decode (/libde265/libde265/build/libde265/liblibde265.so+0xfee95)
    #7 0x55bb6e3b2bc9 in main (/libde265/libde265/build/dec265/dec265+0x6bc9)
    #8 0x7f8a428dfc86 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21c86)
    #9 0x55bb6e3b09b9 in _start (/libde265/libde265/build/dec265/dec265+0x49b9)

Address 0x7ffc2aa1734c is located in stack of thread T0 at offset 10268 in frame
    #0 0x55bb6e3b183a in main (/libde265/libde265/build/dec265/dec265+0x583a)

  This frame has 7 object(s):
    [32, 36) 'option_index'
    [96, 100) 'more'
    [160, 176) 'tv_start'
    [224, 240) 'tv_end'
    [288, 291) 'sc'
    [352, 356) 'len'
    [416, 41376) 'buf' <== Memory access at offset 10268 is inside this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-use-after-scope (/libde265/libde265/build/libde265/liblibde265.so+0x19337f) in void apply_sao_internal<unsigned short>(de265_image*, int, int, slice_segment_header const*, int, int, int, unsigned short const*, int, unsigned short*, int)
Shadow bytes around the buggy address:
  0x10000553ae10: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553ae20: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553ae30: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553ae40: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553ae50: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
=>0x10000553ae60: f8 f8 f8 f8 f8 f8 f8 f8 f8[f8]f8 f8 f8 f8 f8 f8
  0x10000553ae70: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553ae80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553ae90: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553aea0: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x10000553aeb0: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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
==50847==ABORTING

POC

https://github.com/FDU-Sec/poc/blob/main/libde265/poc19

Environment

Ubuntu 18.04.5 LTS
Clang 10.0.1
gcc 7.5.0

Credit

Peng Deng (Fudan University)