Headline
CVE-2020-21600: heap-buffer-overflow in put_weighted_pred_avg_16_fallback when decoding file · Issue #243 · strukturag/libde265
libde265 v1.0.4 contains a heap buffer overflow in the put_weighted_pred_avg_16_fallback function, which can be exploited via a crafted a file.
heap-buffer-overflow in put_weighted_pred_avg_16_fallback when decoding file
I found some problems during fuzzing
Test Version
dev version, git clone https://github.com/strukturag/libde265
Test Environment
root@ubuntu:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.6 LTS
Release: 16.04
Codename: xenial
root@ubuntu:# uname -a
Linux ubuntu 4.15.0-45-generic #4816.04.1-Ubuntu SMP Tue Jan 29 18:03:48 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Test Configure
./configure
configure: ---------------------------------------
configure: Building dec265 example: yes
configure: Building sherlock265 example: no
configure: Building encoder: yes
configure: ---------------------------------------
Test Program
dec265 [infile]
Asan Output
root@ubuntu:~# ./dec265 libde265-put_weighted_pred_avg_16_fallback-heap_overflow.crash
WARNING: pps header invalid
WARNING: non-existing PPS referenced
=================================================================
==103499==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x62a000005310 at pc 0x000000432cd8 bp 0x7ffe393c5a50 sp 0x7ffe393c5a40
WRITE of size 2 at 0x62a000005310 thread T0
#0 0x432cd7 in put_weighted_pred_avg_16_fallback(unsigned short*, long, short const*, short const*, long, int, int, int) /root/src/libde265/libde265/fallback-motion.cc:246
#1 0x52bc12 in acceleration_functions::put_weighted_pred_avg(void*, long, short const*, short const*, long, int, int, int) const ../libde265/acceleration.h:251
#2 0x52085c in generate_inter_prediction_samples(base_context*, slice_segment_header const*, de265_image*, int, int, int, int, int, int, int, PBMotion const*) /root/src/libde265/libde265/motion.cc:513
#3 0x52b8f9 in decode_prediction_unit(base_context*, slice_segment_header const*, de265_image*, PBMotionCoding const&, int, int, int, int, int, int, int, int) /root/src/libde265/libde265/motion.cc:2107
#4 0x478f4a in read_prediction_unit(thread_context*, int, int, int, int, int, int, int, int, int) /root/src/libde265/libde265/slice.cc:4137
#5 0x47a704 in read_coding_unit(thread_context*, int, int, int, int) /root/src/libde265/libde265/slice.cc:4492
#6 0x47b6fe in read_coding_quadtree(thread_context*, int, int, int, int) /root/src/libde265/libde265/slice.cc:4647
#7 0x47338a in read_coding_tree_unit(thread_context*) /root/src/libde265/libde265/slice.cc:2861
#8 0x47beb1 in decode_substream(thread_context*, bool, bool) /root/src/libde265/libde265/slice.cc:4736
#9 0x47db9f in read_slice_segment_data(thread_context*) /root/src/libde265/libde265/slice.cc:5049
#10 0x40bf17 in decoder_context::decode_slice_unit_sequential(image_unit*, slice_unit*) /root/src/libde265/libde265/decctx.cc:843
#11 0x40c6d7 in decoder_context::decode_slice_unit_parallel(image_unit*, slice_unit*) /root/src/libde265/libde265/decctx.cc:945
#12 0x40b589 in decoder_context::decode_some(bool*) /root/src/libde265/libde265/decctx.cc:730
#13 0x40b2f2 in decoder_context::read_slice_NAL(bitreader&, NAL_unit*, nal_header&) /root/src/libde265/libde265/decctx.cc:688
#14 0x40dbb3 in decoder_context::decode_NAL(NAL_unit*) /root/src/libde265/libde265/decctx.cc:1230
#15 0x40e17b in decoder_context::decode(int*) /root/src/libde265/libde265/decctx.cc:1318
#16 0x405a61 in de265_decode /root/src/libde265/libde265/de265.cc:346
#17 0x404972 in main /root/src/libde265/dec265/dec265.cc:764
#18 0x7fa63f83582f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
#19 0x402b28 in _start (/root/dec265+0x402b28)
0x62a000005310 is located 0 bytes to the right of 20752-byte region [0x62a000000200,0x62a000005310)
allocated by thread T0 here:
#0 0x7fa640736076 in __interceptor_posix_memalign (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x99076)
#1 0x43e00d in ALLOC_ALIGNED /root/src/libde265/libde265/image.cc:54
#2 0x43e725 in de265_image_get_buffer /root/src/libde265/libde265/image.cc:132
#3 0x440639 in de265_image::alloc_image(int, int, de265_chroma, std::shared_ptr<seq_parameter_set const>, bool, decoder_context*, long, void*, bool) /root/src/libde265/libde265/image.cc:384
#4 0x43afa4 in decoded_picture_buffer::new_image(std::shared_ptr<seq_parameter_set const>, decoder_context*, long, void*, bool) /root/src/libde265/libde265/dpb.cc:262
#5 0x414467 in decoder_context::process_slice_segment_header(slice_segment_header*, de265_error*, long, nal_header*, void*) /root/src/libde265/libde265/decctx.cc:2012
#6 0x40acad in decoder_context::read_slice_NAL(bitreader&, NAL_unit*, nal_header&) /root/src/libde265/libde265/decctx.cc:639
#7 0x40dbb3 in decoder_context::decode_NAL(NAL_unit*) /root/src/libde265/libde265/decctx.cc:1230
#8 0x40e17b in decoder_context::decode(int*) /root/src/libde265/libde265/decctx.cc:1318
#9 0x405a61 in de265_decode /root/src/libde265/libde265/de265.cc:346
#10 0x404972 in main /root/src/libde265/dec265/dec265.cc:764
#11 0x7fa63f83582f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
SUMMARY: AddressSanitizer: heap-buffer-overflow /root/src/libde265/libde265/fallback-motion.cc:246 put_weighted_pred_avg_16_fallback(unsigned short*, long, short const*, short const*, long, int, int, int)
Shadow bytes around the buggy address:
0x0c547fff8a10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c547fff8a20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c547fff8a30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c547fff8a40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c547fff8a50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c547fff8a60: 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c547fff8a70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c547fff8a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c547fff8a90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c547fff8aa0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c547fff8ab0: 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
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
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
==103499==ABORTING
POC file
libde265-put_weighted_pred_avg_16_fallback-heap_overflow.zip
password: leon.zhao.7
CREDIT
Zhao Liang, Huawei Weiran Labs
Related news
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Ubuntu Security Notice 6617-1 - It was discovered that libde265 could be made to write out of bounds. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. It was discovered that libde265 could be made to write out of bounds. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to cause a denial of service or execute arbitrary code.
Debian Linux Security Advisory 5346-1 - Multiple security issues were discovered in libde265, an implementation of the H.265 video codec which may result in denial of service and potentially the execution of arbitrary code if a malformed media file is processed.