If using legacy (non-prime) surface sharing, only allow surfaces
to be shared between clients with the same master. This will block
malicious clients from peeking at contents at surfaces from other
(possibly vt-switched) masters.
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Reviewed-by: Brian Paul <brianp@xxxxxxxxxx>
---
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index d50cd76..8688e52 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -36,11 +36,13 @@
* @base: The TTM base object handling user-space visibility.
* @srf: The surface metadata.
* @size: TTM accounting size for the surface.
+ * @master: master of the creating client. Used for security check.
*/
struct vmw_user_surface {
struct ttm_prime_object prime;
struct vmw_surface srf;
uint32_t size;
+ struct drm_master *master;
};
/**
@@ -624,6 +626,8 @@ static void vmw_user_surface_free(struct vmw_resource *res)
struct vmw_private *dev_priv = srf->res.dev_priv;
uint32_t size = user_srf->size;
+ if (user_srf->master)
+ drm_master_put(&user_srf->master);
kfree(srf->offsets);
kfree(srf->sizes);
kfree(srf->snooper.image);
@@ -819,6 +823,8 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
user_srf->prime.base.shareable = false;
user_srf->prime.base.tfile = NULL;
+ if (drm_is_legacy_client(file_priv))
+ user_srf->master = drm_master_get(file_priv->master);
/**
* From this point, the generic resource management functions
@@ -885,6 +891,7 @@ vmw_surface_handle_reference(struct vmw_private *dev_priv,
struct ttm_base_object **base_p)
{
struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
+ struct vmw_user_surface *user_srf;
uint32_t handle;
struct ttm_base_object *base;
int ret;
@@ -915,6 +922,21 @@ vmw_surface_handle_reference(struct vmw_private *dev_priv,
}
if (handle_type != DRM_VMW_HANDLE_PRIME) {
+ user_srf = container_of(base, struct vmw_user_surface,
+ prime.base);
+
+ /*
+ * Make sure the surface creator has the same
+ * authenticating master.
+ */
+ if (drm_is_legacy_client(file_priv) &&
+ user_srf->master != file_priv->master) {
+ DRM_ERROR("Trying to reference surface outside of"
+ " master domain.\n");
+ ret = -EACCES;
+ goto out_bad_resource;
+ }
+
ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
if (unlikely(ret != 0)) {
DRM_ERROR("Could not add a reference to a surface.\n");
@@ -1273,6 +1295,8 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
user_srf->prime.base.shareable = false;
user_srf->prime.base.tfile = NULL;
+ if (drm_is_legacy_client(file_priv))
+ user_srf->master = drm_master_get(file_priv->master);
/**
* From this point, the generic resource management functions
--
1.7.10.4
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