Commit 7e9081c5 authored by Gustavo Padovan's avatar Gustavo Padovan
Browse files

drm/fence: fix memory overwrite when setting out_fence fd 



Currently if the userspace declares a int variable to store the out_fence
fd and pass it to OUT_FENCE_PTR the kernel will overwrite the 32 bits
above the int variable on 64 bits systems.

Fix this by making the internal storage of out_fence in the kernel a s32
pointer.

Reported-by: default avatarChad Versace <chadversary@chromium.org>
Signed-off-by: default avatarGustavo Padovan <gustavo.padovan@collabora.com>
Fixes: beaf5af4 ("drm/fence: add out-fences support")
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Rafael Antognolli <rafael.antognolli@intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-and-Tested-by: default avatarChad Versace <chadversary@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1484317329-9293-1-git-send-email-gustavo@padovan.org
parent 3846fd9b

drivers/gpu/drm/drm_atomic.c

+6 −6
Original line number Diff line number Diff line
@@ -291,15 +291,15 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state, 
EXPORT_SYMBOL(drm_atomic_get_crtc_state);



static void set_out_fence_for_crtc(struct drm_atomic_state *state,

				   struct drm_crtc *crtc, s64 __user *fence_ptr)

				   struct drm_crtc *crtc, s32 __user *fence_ptr)

{

	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;

}



static s64 __user *get_out_fence_for_crtc(struct drm_atomic_state *state,

static s32 __user *get_out_fence_for_crtc(struct drm_atomic_state *state,

					  struct drm_crtc *crtc)

{

	s64 __user *fence_ptr;

	s32 __user *fence_ptr;



	fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;

	state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
@@ -512,7 +512,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc, 
		state->color_mgmt_changed |= replaced;

		return ret;

	} else if (property == config->prop_out_fence_ptr) {

		s64 __user *fence_ptr = u64_to_user_ptr(val);

		s32 __user *fence_ptr = u64_to_user_ptr(val);



		if (!fence_ptr)

			return 0;
@@ -1915,7 +1915,7 @@ EXPORT_SYMBOL(drm_atomic_clean_old_fb); 
 */



struct drm_out_fence_state {

	s64 __user *out_fence_ptr;

	s32 __user *out_fence_ptr;

	struct sync_file *sync_file;

	int fd;

};
@@ -1952,7 +1952,7 @@ static int prepare_crtc_signaling(struct drm_device *dev, 
		return 0;



	for_each_crtc_in_state(state, crtc, crtc_state, i) {

		u64 __user *fence_ptr;

		s32 __user *fence_ptr;



		fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);

include/drm/drm_atomic.h

+1 −1
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ struct __drm_crtcs_state { 
	struct drm_crtc *ptr;

	struct drm_crtc_state *state;

	struct drm_crtc_commit *commit;

	s64 __user *out_fence_ptr;

	s32 __user *out_fence_ptr;

};



struct __drm_connnectors_state {

include/drm/drm_mode_config.h

+1 −1
Original line number Diff line number Diff line
@@ -488,7 +488,7 @@ struct drm_mode_config { 
	/**

	 * @prop_out_fence_ptr: Sync File fd pointer representing the

	 * outgoing fences for a CRTC. Userspace should provide a pointer to a

	 * value of type s64, and then cast that pointer to u64.

	 * value of type s32, and then cast that pointer to u64.

	 */

	struct drm_property *prop_out_fence_ptr;

	/**

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