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Re: CVE Requests for FFmpeg 0.9.1
From: "Steven M. Christey" <coley () rcf-smtp mitre org>
Date: Thu, 5 Jan 2012 12:37:44 -0500 (EST)

Michael, this is a well-organized request, thank you!

I tried to sort the issues a little according to type to make this huge
list a bit less ugly. Also feel free to skip things considered too minor, iam not sure where the threshold of "too minor" is.

A couple thoughts on this one, I hope this makes sense.

My VERY limited understanding of ffmpeg is that it is single-user, and it can only process a single file from a single source, without multiple "sessions" or "actions" using data from different sources. If that is the case, then crashers like NULL dereferences and divide-by-zero might not qualify for inclusion in CVE. With products like web browsers and document editors, a crash from one single window or tab could cause a denial of service by closing *other* independent windows or tabs that the user may care about; with things like kernels or servers, a crash affects many sessions and users. So if ffmpeg only processes one file at a time, a basic crasher probably doesn't get a CVE.

If the crash is strongly associated with data integrity, e.g. memory corruption or invalid free's, then it would get a CVE - since we make a conservative assumption that a code-execution exploit *might* be found by someone, and the consequence might be more than DoS. I've been somewhat agnostic about out-of-range reads.

However, such crashes that appear in the *libraries* provided by ffmpeg would qualify, since those libraries might be used in an independent product for which a crash is a security issue (for example, a product might use a library function to convert the audio for a large number of files that have been uploaded from many users, and a single crash prevents other users' files from being converted. In this way, shared libraries are treated more conservatively.)

- Steve

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