On Mon, Sep 23, 2024 at 01:54:58PM +0000, Yonatan Maman wrote: > A copy push command might fail, causing `migrate_to_ram` to return a > dirty HIGH_USER page to the user. > > This exposes a security vulnerability in the nouveau driver. To prevent > memory leaks in `migrate_to_ram` upon a copy error, allocate a zero > page for the destination page. So, you refer to the case where this function fails in nouveau_dmem_copy_one()? If so, can you please explain why adding __GFP_ZERO to alloc_page_vma() helps with that? > > Signed-off-by: Yonatan Maman <Ymaman@xxxxxxxxxx> > Signed-off-by: Gal Shalom <GalShalom@xxxxxxxxxx> Since this is a bug, please also add a 'Fixes' tag, CC stable and add a 'Co-developed-by' tag if appropriate. > --- > drivers/gpu/drm/nouveau/nouveau_dmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c > index 6fb65b01d778..097bd3af0719 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_dmem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c > @@ -193,7 +193,7 @@ static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf) > if (!spage || !(src & MIGRATE_PFN_MIGRATE)) > goto done; > > - dpage = alloc_page_vma(GFP_HIGHUSER, vmf->vma, vmf->address); > + dpage = alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO, vmf->vma, vmf->address); > if (!dpage) > goto done; > > -- > 2.34.1 >
