On Mon, Jun 24, 2019 at 04:32:55PM +0200, Andrey Konovalov wrote: > This patch is a part of a series that extends kernel ABI to allow to pass > tagged user pointers (with the top byte set to something else other than > 0x00) as syscall arguments. > > In radeon_gem_userptr_ioctl() an MMU notifier is set up with a (tagged) > userspace pointer. The untagged address should be used so that MMU > notifiers for the untagged address get correctly matched up with the right > BO. This funcation also calls radeon_ttm_tt_pin_userptr(), which uses > provided user pointers for vma lookups, which can only by done with > untagged pointers. > > This patch untags user pointers in radeon_gem_userptr_ioctl(). > > Suggested-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> > Acked-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees > --- > drivers/gpu/drm/radeon/radeon_gem.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c > index 44617dec8183..90eb78fb5eb2 100644 > --- a/drivers/gpu/drm/radeon/radeon_gem.c > +++ b/drivers/gpu/drm/radeon/radeon_gem.c > @@ -291,6 +291,8 @@ int radeon_gem_userptr_ioctl(struct drm_device *dev, void *data, > uint32_t handle; > int r; > > + args->addr = untagged_addr(args->addr); > + > if (offset_in_page(args->addr | args->size)) > return -EINVAL; > > -- > 2.22.0.410.gd8fdbe21b5-goog > -- Kees Cook
