Hello, Sinclair! > Here, the check should be "> DRM_VMW_MAX_MIP_LEVELS" because req->mip_levels > is only for one layer. Got it, thanks! > Also, as long as we can doing a check, I would suggest we check for 0 as > well. Do you mean a check for "req->mip_levels > 0" or for "req->mip_levels >= 0" ? I glimpsed thru the code and I do not see problems with req->mip_levels being 0, surely I may be mistaking. Best regards, Vladis Dronov | Red Hat, Inc. | Product Security Engineer ----- Original Message ----- From: "Sinclair Yeh" <syeh@xxxxxxxxxx> To: "Vladis Dronov" <vdronov@xxxxxxxxxx> Cc: "VMware Graphics" <linux-graphics-maintainer@xxxxxxxxxx>, "Thomas Hellstrom" <thellstrom@xxxxxxxxxx>, "David Airlie" <airlied@xxxxxxxx>, dri-devel@xxxxxxxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx Sent: Friday, March 31, 2017 5:07:12 PM Subject: Re: [PATCH] kernel: drm/vmwgfx: limit the number of mip levels in vmw_gb_surface_define_ioctl() Hi Vladis, On Thu, Mar 30, 2017 at 12:27:12PM +0200, Vladis Dronov wrote: > The 'req->mip_levels' parameter in vmw_gb_surface_define_ioctl() is > a user-controlled 'uint32_t' value which is used as a loop count limit. > This can lead to a kernel lockup and DoS. Add check for 'req->mip_levels'. > > References: > https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.redhat.com_show-5Fbug.cgi-3Fid-3D1437431&d=DwIBAg&c=uilaK90D4TOVoH58JNXRgQ&r=HaJ2a6NYExoV0cntAYcoqA&m=5yR87BuuU86aoAjCveInxh6jvgOyumqIHQhTs0xLo38&s=tWQs7vwNLgD_b2RWMddVtusEKh9FQTIF5rKFOWudslE&e= > Signed-off-by: Vladis Dronov <vdronov@xxxxxxxxxx> > --- > drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c > index b445ce9..b30824b 100644 > --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c > +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c > @@ -1281,6 +1281,10 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data, > if (req->multisample_count != 0) > return -EINVAL; > > + if (req->mip_levels > DRM_VMW_MAX_SURFACE_FACES * > + DRM_VMW_MAX_MIP_LEVELS) > + return -EINVAL; > + Here, the check should be "> DRM_VMW_MAX_MIP_LEVELS" because req->mip_levels is only for one layer. Also, as long as we can doing a check, I would suggest we check for 0 as well. Sinclair _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
