drm/ttm, drm/vmwgfx: Relax permission checking when opening surfaces

Previously, when a surface was opened using a legacy (non prime) handle,
it was verified to have been created by a client in the same master realm.
Relax this so that opening is also allowed recursively if the client
already has the surface open.

This works around a regression in svga mesa where opening of a shared
surface is used recursively to obtain surface information.

Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>

5 files changed, 24 insertions, 23 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_object.c b/drivers/gpu/drm/ttm/ttm_object.c
index fdb451e3ec01..d750140bafbc 100644
--- a/drivers/gpu/drm/ttm/ttm_object.c
+++ b/drivers/gpu/drm/ttm/ttm_object.c
@@ -179,7 +179,7 @@ int ttm_base_object_init(struct ttm_object_file *tfile,
         if (unlikely(ret != 0))
                 goto out_err0;
 
-        ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
+        ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
         if (unlikely(ret != 0))
                 goto out_err1;
 
@@ -318,7 +318,8 @@ EXPORT_SYMBOL(ttm_ref_object_exists);
 
 int ttm_ref_object_add(struct ttm_object_file *tfile,
                        struct ttm_base_object *base,
-                       enum ttm_ref_type ref_type, bool *existed)
+                       enum ttm_ref_type ref_type, bool *existed,
+                       bool require_existed)
 {
         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
         struct ttm_ref_object *ref;
@@ -345,6 +346,9 @@ int ttm_ref_object_add(struct ttm_object_file *tfile,
                 }
 
                 rcu_read_unlock();
+                if (require_existed)
+                        return -EPERM;
+
                 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
                                            false, false);
                 if (unlikely(ret != 0))
@@ -635,7 +639,7 @@ int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
         prime = (struct ttm_prime_object *) dma_buf->priv;
         base = &prime->base;
         *handle = base->hash.key;
-        ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
+        ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
 
         dma_buf_put(dma_buf);
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index 4076063e0fdd..6b2708b4eafe 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -1075,10 +1075,8 @@ int vmw_fence_event_ioctl(struct drm_device *dev, void *data,
                 (void) vmw_fence_obj_reference(fence);
 
                 if (user_fence_rep != NULL) {
-                        bool existed;
-
-                        ret = ttm_ref_object_add(tfile, base,
-                                                 TTM_REF_USAGE, &existed);
+                        ret = ttm_ref_object_add(vmw_fp->tfile, base,
+                                                 TTM_REF_USAGE, NULL, false);
                         if (unlikely(ret != 0)) {
                                 DRM_ERROR("Failed to reference a fence "
                                           "object.\n");
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index 65b3f0369636..bf23153d4f55 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -589,7 +589,7 @@ static int vmw_user_dmabuf_synccpu_grab(struct vmw_user_dma_buffer *user_bo,
                 return ret;
 
         ret = ttm_ref_object_add(tfile, &user_bo->prime.base,
-                                 TTM_REF_SYNCCPU_WRITE, &existed);
+                                 TTM_REF_SYNCCPU_WRITE, &existed, false);
         if (ret != 0 || existed)
                 ttm_bo_synccpu_write_release(&user_bo->dma.base);
 
@@ -773,7 +773,7 @@ int vmw_user_dmabuf_reference(struct ttm_object_file *tfile,
 
         *handle = user_bo->prime.base.hash.key;
         return ttm_ref_object_add(tfile, &user_bo->prime.base,
-                                  TTM_REF_USAGE, NULL);
+                                  TTM_REF_USAGE, NULL, false);
 }
 
 /*
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index f410502cb075..adc023fe67f3 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -891,17 +891,16 @@ vmw_surface_handle_reference(struct vmw_private *dev_priv,
         uint32_t handle;
         struct ttm_base_object *base;
         int ret;
+        bool require_exist = false;
 
         if (handle_type == DRM_VMW_HANDLE_PRIME) {
                 ret = ttm_prime_fd_to_handle(tfile, u_handle, &handle);
                 if (unlikely(ret != 0))
                         return ret;
         } else {
-                if (unlikely(drm_is_render_client(file_priv))) {
-                        DRM_ERROR("Render client refused legacy "
-                                  "surface reference.\n");
-                        return -EACCES;
-                }
+                if (unlikely(drm_is_render_client(file_priv)))
+                        require_exist = true;
+
                 if (ACCESS_ONCE(vmw_fpriv(file_priv)->locked_master)) {
                         DRM_ERROR("Locked master refused legacy "
                                   "surface reference.\n");
@@ -929,17 +928,14 @@ vmw_surface_handle_reference(struct vmw_private *dev_priv,
 
                 /*
                  * Make sure the surface creator has the same
-                 * authenticating master.
+                 * authenticating master, or is already registered with us.
                  */
                 if (drm_is_primary_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;
-                }
+                    user_srf->master != file_priv->master)
+                        require_exist = true;
 
-                ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
+                ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL,
+                                         require_exist);
                 if (unlikely(ret != 0)) {
                         DRM_ERROR("Could not add a reference to a surface.\n");
                         goto out_bad_resource;
diff --git a/include/drm/ttm/ttm_object.h b/include/drm/ttm/ttm_object.h
index ed953f98f0e1..1487011fe057 100644
--- a/include/drm/ttm/ttm_object.h
+++ b/include/drm/ttm/ttm_object.h
@@ -229,6 +229,8 @@ extern void ttm_base_object_unref(struct ttm_base_object **p_base);
  * @ref_type: The type of reference.
  * @existed: Upon completion, indicates that an identical reference object
  * already existed, and the refcount was upped on that object instead.
+ * @require_existed: Fail with -EPERM if an identical ref object didn't
+ * already exist.
  *
  * Checks that the base object is shareable and adds a ref object to it.
  *
@@ -243,7 +245,8 @@ extern void ttm_base_object_unref(struct ttm_base_object **p_base);
  */
 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
                               struct ttm_base_object *base,
-                              enum ttm_ref_type ref_type, bool *existed);
+                              enum ttm_ref_type ref_type, bool *existed,
+                              bool require_existed);
 
 extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
                                   struct ttm_base_object *base);