[PATCH] kernel: drm/vmwgfx: limit the number of mip levels in vmw_gb_surface_define_ioctl()
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://bugzilla.redhat.com/show_bug.cgi?id=1437431 Signed-off-by: Vladis Dronov vdronov@redhat.com --- 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; + if (unlikely(vmw_user_surface_size == 0)) vmw_user_surface_size = ttm_round_pot(sizeof(*user_srf)) + 128;
This flaw was assigned an id CVE-2017-7346 by MITRE:
http://seclists.org/oss-sec/2017/q1/696
Best regards, Vladis Dronov | Red Hat, Inc. | Product Security Engineer
----- Original Message ----- From: "Vladis Dronov" vdronov@redhat.com To: "VMware Graphics" linux-graphics-maintainer@vmware.com, "Sinclair Yeh" syeh@vmware.com, "Thomas Hellstrom" thellstrom@vmware.com, "David Airlie" airlied@linux.ie, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: "Vladis Dronov" vdronov@redhat.com Sent: Thursday, March 30, 2017 12:27:12 PM Subject: [PATCH] kernel: drm/vmwgfx: limit the number of mip levels in vmw_gb_surface_define_ioctl()
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://bugzilla.redhat.com/show_bug.cgi?id=1437431 Signed-off-by: Vladis Dronov vdronov@redhat.com
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@vmware.com To: "Vladis Dronov" vdronov@redhat.com Cc: "VMware Graphics" linux-graphics-maintainer@vmware.com, "Thomas Hellstrom" thellstrom@vmware.com, "David Airlie" airlied@linux.ie, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org 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:
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@lists.freedesktop.org
-
Sinclair Yeh -
Vladis Dronov