On Sat, Jun 03, 2017 at 09:20:04PM +0200, Michael Niedermayer wrote: > This reduces the attack surface of local file-system > information leaking. > > It prevents the existing exploit leading to an information leak. As > well as similar hypothetical attacks. > > Leaks of information from files and symlinks ending in common multimedia > extensions > are still possible. But files with sensitive information like private keys > and passwords > generally do not use common multimedia filename extensions. > It does not stop leaks via remote addresses in the LAN. > > The existing exploit depends on a specific decoder as well. > It does appear though that the exploit should be possible with any decoder. > The problem is that as long as sensitive information gets into the decoder, > the output of the decoder becomes sensitive as well. > The only obvious solution is to prevent access to sensitive information. Or to > disable hls or possibly some of its feature. More complex solutions like > checking the path to limit access to only subdirectories of the hls path may > work as an alternative. But such solutions are fragile and tricky to implement > portably and would not stop every possible attack nor would they work with all > valid hls files. > > Developers have expressed their dislike / objected to disabling hls by > default as well > as disabling hls with local files. There also where objections against > restricting > remote url file extensions. This here is a less robust but also lower > inconvenience solution. > It can be applied stand alone or together with other solutions. > > Found-by: Emil Lerner and Pavel Cheremushkin > Reported-by: Thierry Foucu <tfo...@google.com> > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > --- > libavformat/hls.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-)
Applied with the author name joke suggested by nicolas Thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Let us carefully observe those good qualities wherein our enemies excel us and endeavor to excel them, by avoiding what is faulty, and imitating what is excellent in them. -- Plutarch
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