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[209.85.166.50]) by smtp.gmail.com with ESMTPSA id i1sm6506057iov.10.2021.12.17.13.09.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Dec 2021 13:09:25 -0800 (PST) Received: by mail-io1-f50.google.com with SMTP id 14so4790555ioe.2 for ; Fri, 17 Dec 2021 13:09:25 -0800 (PST) X-Received: by 2002:a5e:da06:: with SMTP id x6mr2724456ioj.139.1639775365241; Fri, 17 Dec 2021 13:09:25 -0800 (PST) MIME-Version: 1.0 References: <20211213054336.19783-1-pal@sandflow.com> <163947788654.13029.10298345109744593134@lain.red.khirnov.net> <163950889025.13443.18056291142265665105@lain.red.khirnov.net> <163959962513.13029.16441945709966296103@lain.red.khirnov.net> <163975114109.13029.10142418833883066194@lain.red.khirnov.net> In-Reply-To: From: Pierre-Anthony Lemieux Date: Fri, 17 Dec 2021 13:09:12 -0800 X-Gmail-Original-Message-ID: Message-ID: To: FFmpeg development discussions and patches Subject: Re: [FFmpeg-devel] [PATCH v10 1/2] avformat/imf: Demuxer X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On Fri, Dec 17, 2021 at 12:54 PM Lynne wrote: > > Dec 17, 2021, 3:25 PM by anton@khirnov.net: > > > Quoting Pierre-Anthony Lemieux (2021-12-15 21:41:25) > > > >> On Wed, Dec 15, 2021 at 12:20 PM Anton Khirnov wrote: > >> > > >> > Quoting Pierre-Anthony Lemieux (2021-12-15 01:17:26) > >> > > > > >> > > > Now the question is whether a malicious attacker can craft those two > >> > > > files to get access to anything they shouldn't. I suppose at the very > >> > > > least the attacker can get information that the user opened the file (by > >> > > > adding an asset on an attacker's server) but that will be a danger with > >> > > > any playlists allowing network resources and can be controlled with > >> > > > io_open(). Can you think of any other possible issues? > >> > > > > >> > > > >> > > Some security considerations: > >> > > > >> > > - a DDoS can conceivably occur if a malicious CPL+ASSETMAP is widely > >> > > distributed. Both an ASSETMAP and a CPL are required since (a) the CPL > >> > > does not contain paths/hyperlinks and (b) only those resources > >> > > referenced by the CPL are fetched using the ASSETMAP. > >> > > - the CPL uses XML, which has its own security considerations. For > >> > > example, XML parsing can result in entities being fetched over the > >> > > network, but this is disabled by default in libxml AFAIK. > >> > > >> > This is concerning. From a brief glance at libxml2, it seems that you > >> > need to pass XML_PARSE_NONET as the last parameter to xmlReadMemory() to > >> > actually disabling network fetching. > >> > But it is possible I'm misreading the code, so if you or anyone else > >> > understands this better then clarifications are welcome. > >> > >> I was referring to entity expansion and the loading of DTDs being > >> disabled by default -- see XML_PARSE_NOENT and XML_PARSE_DTDLOAD at > >> [1-2]. > >> > > > > Okay then. If nobody has further comments, I will push your latest patch > > in a few days. > > > > I think this shouldn't get merged into 5.0. It would get minimal amount > of fuzzing if it does now, so let's leave it for a later release? What amount of fuzzing are you looking for? Is there an HLS and/or DASH equivalent? Happy to put in the work to make it happen. > I'd still like to see libuuid being used, we have several uses for it already. libuuid is not an obvious match with the IMF demuxer -- see details in previous thread. I am happy to work on a UUID refactoring across libavformat, but this is a separable task with impact on several other modules. > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".