Project: gpac (gpac/gpac), language: c++
Vulnerability instance: gpac.cve-2019-20628
Sanitizer: address

================= Bug Report (1/1) ==================
## Source: GitHub Issue
## URL: https://github.com/gpac/gpac/issues/1269
## Description:
Issue: gpac/gpac#1269
Title: Use After Free (mpegts.c:2183)
State: closed
Created by: strongcourage
Created at: 2019-07-06 00:10:37+00:00

Issue Body:
Hi,
Our fuzzer found an UAF on MP4Box (the latest commit 987169b on master).
PoC: https://github.com/strongcourage/PoCs/blob/master/gpac_987169b/PoC_uaf_mpegts.c:2183
Command: MP4Box -info $PoC
ASAN says:
~~~
==12341==ERROR: AddressSanitizer: heap-use-after-free on address 0x60300000efb0 at pc 0x00000098190d bp 0x7ffd5d0bb3c0 sp 0x7ffd5d0bb3b0
WRITE of size 2 at 0x60300000efb0 thread T0
    #0 0x98190c in gf_m2ts_process_pmt /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:2183
    #1 0x970944 in gf_m2ts_section_complete /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:1610
    #2 0x971fa2 in gf_m2ts_gather_section /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:1740
    #3 0x97991c in gf_m2ts_process_packet /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:3446
    #4 0x97991c in gf_m2ts_process_data /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:3507
    #5 0x986f65 in gf_m2ts_probe_file /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:4641
    #6 0x963fa9 in gf_media_import /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/media_import.c:10998
    #7 0x45b475 in convert_file_info /home/dungnguyen/gueb-testing/gpac-head/applications/mp4box/fileimport.c:124
    #8 0x43ac0c in mp4boxMain /home/dungnguyen/gueb-testing/gpac-head/applications/mp4box/main.c:4804
    #9 0x7f58ce76782f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #10 0x421eb8 in _start (/home/dungnguyen/PoCs/gpac_987169b/MP4Box-asan+0x421eb8)

0x60300000efb0 is located 0 bytes inside of 26-byte region [0x60300000efb0,0x60300000efca)
freed by thread T0 here:
    #0 0x7f58d022d961 in realloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98961)
    #1 0x972421 in gf_m2ts_gather_section /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:1730

previously allocated by thread T0 here:
    #0 0x7f58d022d602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
    #1 0x972081 in gf_m2ts_gather_section /home/dungnguyen/gueb-testing/gpac-head/src/media_tools/mpegts.c:1705
~~~
Thanks,
Manh Dung


Comments:
Comment by jeanlf on 2019-07-07 15:59:16+00:00:
thanks for the report, now fixed

Build script:
#!/bin/bash -eu
# Minimized build script with only core build commands
set -eu
./configure --static-build --extra-cflags="${CFLAGS}" --extra-ldflags="${CFLAGS}"
make -j$(nproc)

Dockerfile:
FROM hwiwonlee/secb.base:latest
RUN apt-get update && apt-get install -y build-essential pkg-config libz-dev
RUN git clone https://github.com/gpac/gpac gpac
RUN git -C gpac checkout 1ab4860609f2e7a35634930571e7d0531297e090
WORKDIR $SRC/gpac
COPY build.sh $SRC/

Additional files:
filename: fuzz_parse.c
content: /* Copyright 2021 Google LLC
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
      http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#include <stdio.h>
#include <unistd.h>

#include <gpac/internal/isomedia_dev.h>
#include <gpac/constants.h>

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
    char filename[256];
    sprintf(filename, "/tmp/libfuzzer.%d", getpid());

    FILE *fp = fopen(filename, "wb");
    if (!fp) {
        return 0;
    }
    fwrite(data, size, 1, fp);
    fclose(fp);

    GF_ISOFile *movie = NULL;
    movie = gf_isom_open_file(filename, GF_ISOM_OPEN_READ_DUMP, NULL);
    if (movie != NULL) {
        gf_isom_close(movie);
    }
    unlink(filename);
    return 0;
}