On Tue, Sep 29, 2020 at 10:23:50AM -0700, Linus Torvalds wrote: > On Tue, Sep 29, 2020 at 5:16 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote: > > > > OK, so it seems that reverting comes out as the best choice here. > > Yeah. > > > BTW, I'm looking at rw_verify_area() and I see this "If (ppos)" check > > and the comment above it... And then I look at autofs_write(), which > > passes &file->f_pos, while ksys_write() passes file_ppos(file) > > Ok, that doesn't matter for the security_file_permission() issue, but > yes, autofs is doing the traditional thing, and it's pointless. Using > file_ppos(file) isn't an option since it's an inline to read_write.c, > but it could just pass in NULL these days and avoid that too. > > So how about we just do the appended patch? Can whoever sees this > problem just verify, even though it looks trivially correct... This looks sensible to me. I'd throw in a /* only for autofs, don't use in new code */ near the export, but users of these kind of functions tend to be blind copy and paste code anyway, so the comment probably isn't even read by the relevant parties..
