2017-04-06 12:34:06

by Vladis Dronov

Subject: [PATCH v2] 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 <[email protected]>
---
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index b445ce9..e0d7ff9 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -1281,6 +1281,9 @@ 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_MIP_LEVELS)
+ return -EINVAL;
+
if (unlikely(vmw_user_surface_size == 0))
vmw_user_surface_size = ttm_round_pot(sizeof(*user_srf)) +
128;
--
2.9.3

2017-04-19 20:56:18

by Sinclair Yeh

Subject: Re: [PATCH v2] kernel: drm/vmwgfx: limit the number of mip levels in vmw_gb_surface_define_ioctl()

Thanks Vladis!

Reviewed-by: Sinclair Yeh <[email protected]>

On Thu, Apr 06, 2017 at 02:33:40PM +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=D9ZabTkAbhTqB-puuJ1a4SnWKUIGw0oXestkhJG6dCQ&s=6PZxBQ8MQjy-uc5pd6vyZg3D5yrG0jlSPi5pPE0oFK4&e=
> Signed-off-by: Vladis Dronov <[email protected]>
> ---
> drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> index b445ce9..e0d7ff9 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> @@ -1281,6 +1281,9 @@ 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_MIP_LEVELS)
> + return -EINVAL;
> +
> if (unlikely(vmw_user_surface_size == 0))
> vmw_user_surface_size = ttm_round_pot(sizeof(*user_srf)) +
> 128;
> --
> 2.9.3
>