On Fri, Aug 03, 2018 at 04:59:18PM +0200, Andrey Konovalov wrote: > On Thu, Aug 2, 2018 at 5:00 PM, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > > On Wed, Aug 1, 2018 at 7:42 PM, Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > >> On Mon, Jul 16, 2018 at 01:25:59PM +0200, Andrey Konovalov wrote: > >>> On Thu, Jun 28, 2018 at 9:30 PM, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > >>> So the checker reports ~100 different places where a __user pointer > >>> being casted. I've looked through them and found 3 places where we > >>> need to add untagging. Source code lines below come from 4.18-rc2+ > >>> (6f0d349d). > >> [...] > >>> I'll add the 3 patches with fixes to v5 of this patchset. > >> > >> Thanks for investigating. You can fix those three places in your code > > > > OK, will do. > > > >> but I was rather looking for a way to check such casting in the future > >> for newly added code. While for the khwasan we can assume it's a debug > >> option, the tagged user pointers are ABI and we need to keep it stable. > >> > >> We could we actually add some macros for explicit conversion between > >> __user ptr and long and silence the warning there (I guess this would > >> work better for sparse). We can then detect new ptr to long casts as > >> they appear. I just hope that's not too intrusive. > >> > >> (I haven't tried the sparse patch yet, hopefully sometime this week) > > > > Haven't look at that sparse patch yet myself, but sounds doable. > > Should these macros go into this patchset or should they go > > separately? > > Started looking at this. When I run sparse with default checks enabled > (make C=1) I get countless warnings. Does anybody actually use it? Try using a more up-to-date version of sparse. Odds are you are using an old one, there is a newer version in a different branch on kernel.org somewhere... greg k-h
