A malicious caller could otherwise hand over handles to other objects causing all sorts of interesting problems.
Testing done: Ran a Fedora 25 desktop using both Xorg and gnome-shell/Wayland.
Cc: stable@vger.kernel.org Signed-off-by: Thomas Hellstrom thellstrom@vmware.com Reviewed-by: Sinclair Yeh syeh@vmware.com --- drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 77 +++++++++++++++++++++++------------ 1 file changed, 50 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c index 6541dd8..4076063 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c @@ -538,7 +538,7 @@ int vmw_fence_create(struct vmw_fence_manager *fman, struct vmw_fence_obj **p_fence) { struct vmw_fence_obj *fence; - int ret; + int ret;
fence = kzalloc(sizeof(*fence), GFP_KERNEL); if (unlikely(fence == NULL)) @@ -701,6 +701,41 @@ void vmw_fence_fifo_up(struct vmw_fence_manager *fman) }
+/** + * vmw_fence_obj_lookup - Look up a user-space fence object + * + * @tfile: A struct ttm_object_file identifying the caller. + * @handle: A handle identifying the fence object. + * @return: A struct vmw_user_fence base ttm object on success or + * an error pointer on failure. + * + * The fence object is looked up and type-checked. The caller needs + * to have opened the fence object first, but since that happens on + * creation and fence objects aren't shareable, that's not an + * issue currently. + */ +static struct ttm_base_object * +vmw_fence_obj_lookup(struct ttm_object_file *tfile, u32 handle) +{ + struct ttm_base_object *base = ttm_base_object_lookup(tfile, handle); + + if (!base) { + pr_err("Invalid fence object handle 0x%08lx.\n", + (unsigned long)handle); + return ERR_PTR(-EINVAL); + } + + if (base->refcount_release != vmw_user_fence_base_release) { + pr_err("Invalid fence object handle 0x%08lx.\n", + (unsigned long)handle); + ttm_base_object_unref(&base); + return ERR_PTR(-EINVAL); + } + + return base; +} + + int vmw_fence_obj_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { @@ -726,13 +761,9 @@ int vmw_fence_obj_wait_ioctl(struct drm_device *dev, void *data, arg->kernel_cookie = jiffies + wait_timeout; }
- base = ttm_base_object_lookup(tfile, arg->handle); - if (unlikely(base == NULL)) { - printk(KERN_ERR "Wait invalid fence object handle " - "0x%08lx.\n", - (unsigned long)arg->handle); - return -EINVAL; - } + base = vmw_fence_obj_lookup(tfile, arg->handle); + if (IS_ERR(base)) + return PTR_ERR(base);
fence = &(container_of(base, struct vmw_user_fence, base)->fence);
@@ -771,13 +802,9 @@ int vmw_fence_obj_signaled_ioctl(struct drm_device *dev, void *data, struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile; struct vmw_private *dev_priv = vmw_priv(dev);
- base = ttm_base_object_lookup(tfile, arg->handle); - if (unlikely(base == NULL)) { - printk(KERN_ERR "Fence signaled invalid fence object handle " - "0x%08lx.\n", - (unsigned long)arg->handle); - return -EINVAL; - } + base = vmw_fence_obj_lookup(tfile, arg->handle); + if (IS_ERR(base)) + return PTR_ERR(base);
fence = &(container_of(base, struct vmw_user_fence, base)->fence); fman = fman_from_fence(fence); @@ -1024,6 +1051,7 @@ int vmw_fence_event_ioctl(struct drm_device *dev, void *data, (struct drm_vmw_fence_event_arg *) data; struct vmw_fence_obj *fence = NULL; struct vmw_fpriv *vmw_fp = vmw_fpriv(file_priv); + struct ttm_object_file *tfile = vmw_fp->tfile; struct drm_vmw_fence_rep __user *user_fence_rep = (struct drm_vmw_fence_rep __user *)(unsigned long) arg->fence_rep; @@ -1037,15 +1065,11 @@ int vmw_fence_event_ioctl(struct drm_device *dev, void *data, */ if (arg->handle) { struct ttm_base_object *base = - ttm_base_object_lookup_for_ref(dev_priv->tdev, - arg->handle); - - if (unlikely(base == NULL)) { - DRM_ERROR("Fence event invalid fence object handle " - "0x%08lx.\n", - (unsigned long)arg->handle); - return -EINVAL; - } + vmw_fence_obj_lookup(tfile, arg->handle); + + if (IS_ERR(base)) + return PTR_ERR(base); + fence = &(container_of(base, struct vmw_user_fence, base)->fence); (void) vmw_fence_obj_reference(fence); @@ -1053,7 +1077,7 @@ int vmw_fence_event_ioctl(struct drm_device *dev, void *data, if (user_fence_rep != NULL) { bool existed;
- ret = ttm_ref_object_add(vmw_fp->tfile, base, + ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, &existed); if (unlikely(ret != 0)) { DRM_ERROR("Failed to reference a fence " @@ -1097,8 +1121,7 @@ int vmw_fence_event_ioctl(struct drm_device *dev, void *data, return 0; out_no_create: if (user_fence_rep != NULL) - ttm_ref_object_base_unref(vmw_fpriv(file_priv)->tfile, - handle, TTM_REF_USAGE); + ttm_ref_object_base_unref(tfile, handle, TTM_REF_USAGE); out_no_ref_obj: vmw_fence_obj_unreference(&fence); return ret;