On Tue, Oct 23, 2018 at 4:21 AM Johan Hovold <johan@xxxxxxxxxx> wrote: > > Hi Rob, > > On Tue, Sep 04, 2018 at 03:05:57PM +0200, Johan Hovold wrote: > > Hi all, > > > > On Mon, Aug 27, 2018 at 10:21:44AM +0200, Johan Hovold wrote: > > > Several drivers currently use of_find_compatible_node() to lookup child > > > nodes while failing to notice that the of_find_ functions search the > > > entire tree depth-first (from a given start node) and therefore can > > > match unrelated nodes. > > > > > > The fact that these functions also drop a reference to the node they > > > start searching from (e.g. the parent node) is typically also > > > overlooked, something which can lead to use-after-free bugs (e.g. after > > > probe deferrals). > > > > > > This series adds a new helper, similar to of_get_child_by_name(), > > > that can be used to lookup compatible child nodes, and uses the new > > > helper to fix child-node lookups throughout the tree. > > > > > > This is related to the fixes I posted about a year ago, which addressed > > > a similar anti-pattern when looking up child nodes by name. Since it > > > took me more than a year to get all those fixes into Linus' tree (one > > > fix is still pending), and as these fixes depend on the new helper, I'm > > > suggesting that these all go in through Rob's or Greg's trees. > > > > > > Alternatively, the helper could go into to -rc2, and I'll be pinging > > > submaintainers for the coming year as well. ;) > > > > Rob has gotten the helper into -rc2 now: > > > > 36156f9241cb of: add helper to lookup compatible child node > > > > so feel free to pick these fixes up directly for 4.19-rc or -next, > > whichever you prefer. I've been able to trigger crashes after probe > > deferrals due to the use-after-free, but this seems unlikely to be > > exploitable. > > > > I think Rob will be picking up any patches that remain by the end of the > > release cycle for 4.20. > > So far only Ulf has picked up the mmc patch below directly, so if you > could take the rest through your tree for -rc1 that would be great. Thanks for the reminder, though before the merge window opened would have been better. I've applied all but the mtd patch. Rob
