On Mon, Aug 10, 2020 at 06:37:17PM +0200, Pavel Machek wrote: > Hi! > > > commit 80982c7e834e5d4e325b6ce33757012ecafdf0bb upstream. > > > > Some ioctls via OSS sequencer API may race and lead to UAF when the > > port create and delete are performed concurrently, as spotted by a > > couple of syzkaller cases. This patch is an attempt to address it by > > serializing the ioctls with the existing register_mutex. > > > > Basically OSS sequencer API is an obsoleted interface and was designed > > without much consideration of the concurrency. There are very few > > applications with it, and the concurrent performance isn't asked, > > hence this "big hammer" approach should be good enough. > > That really is a "big hammer". And I believe it is too big. Please discuss code architecture decisions on the mailing list for the subsystem/patch. Doing it in random stable backports does not help out as all of the developers involved are not copied here. thanks, greg k-h
