On Fri, Jan 10, 2025 at 02:21:22PM +0000, Günther Noack wrote: > With this, processes without CAP_SYS_ADMIN are able to use TIOCLINUX with > subcode TIOCL_SETSEL, in the selection modes TIOCL_SETPOINTER, > TIOCL_SELCLEAR and TIOCL_SELMOUSEREPORT. > > TIOCL_SETSEL was previously changed to require CAP_SYS_ADMIN, as this IOCTL > let callers change the selection buffer and could be used to simulate > keypresses. These three TIOCL_SETSEL selection modes, however, are safe to > use, as they do not modify the selection buffer. > > This fixes a mouse support regression that affected Emacs (invisible mouse > cursor). > > Cc: stable@xxxxxxxxxxxxxxx > Link: https://lore.kernel.org/r/ee3ec63269b43b34e1c90dd8c9743bf8@xxxxxxxxxx > Fixes: 8d1b43f6a6df ("tty: Restrict access to TIOCLINUX' copy-and-paste subcommands") > Signed-off-by: Günther Noack <gnoack@xxxxxxxxxx> > --- > Changes in V2: > > * Removed comment in vt.c (per Greg's suggestion) > > * CC'd stable@ > > * I *kept* the CAP_SYS_ADMIN check *after* copy_from_user(), > with the reasoning that: > > 1. I do not see a good alternative to reorder the code here. > We need the data from copy_from_user() in order to know whether > the CAP_SYS_ADMIN check even needs to be performed. > 2. A previous get_user() from an adjacent memory region already worked > (making this a very unlikely failure) > > I would still appreciate a more formal Tested-by from Hanno (hint, hint) :) This really is v3, as you sent a v2 last year, right? b4 got really confused, but I think I figured it out. Whenever you resend, bump the version number please, otherwise it causes problems. Remember, some of use deal with thousands of patches a week... thanks, greg k-h
