From: jsg <jsg@openbsd.org>
Date: Fri, 4 Aug 2023 09:22:11 +0000 (+0000)
Subject: drm/amd/display: perform a bounds check before filling dirty rectangles
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=5ab3b98d3acdd347b9d86b0c25b3302f362e93ba;p=openbsd

drm/amd/display: perform a bounds check before filling dirty rectangles

From Hamza Mahfooz
d58fb94f24f89c833bd73d370b27b58867d78120 in linux-6.1.y/6.1.43
af22d6a869cc26b519bfdcd54293c53f2e491870 in mainline linux
---

diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 334715326a5..328111f4a67 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4955,11 +4955,7 @@ static inline void fill_dc_dirty_rect(struct drm_plane *plane,
 				      int32_t y, int32_t width, int32_t height,
 				      int *i, bool ffu)
 {
-	if (*i > DC_MAX_DIRTY_RECTS)
-		return;
-
-	if (*i == DC_MAX_DIRTY_RECTS)
-		goto out;
+	WARN_ON(*i >= DC_MAX_DIRTY_RECTS);
 
 	dirty_rect->x = x;
 	dirty_rect->y = y;
@@ -4975,7 +4971,6 @@ static inline void fill_dc_dirty_rect(struct drm_plane *plane,
 			"[PLANE:%d] PSR SU dirty rect at (%d, %d) size (%d, %d)",
 			plane->base.id, x, y, width, height);
 
-out:
 	(*i)++;
 }
 
@@ -5057,6 +5052,9 @@ static void fill_dc_dirty_rects(struct drm_plane *plane,
 		new_plane_state->plane->base.id,
 		bb_changed, fb_changed, num_clips);
 
+	if ((num_clips + (bb_changed ? 2 : 0)) > DC_MAX_DIRTY_RECTS)
+		goto ffu;
+
 	if (bb_changed) {
 		fill_dc_dirty_rect(new_plane_state->plane, &dirty_rects[i],
 				   new_plane_state->crtc_x,
@@ -5086,9 +5084,6 @@ static void fill_dc_dirty_rects(struct drm_plane *plane,
 				   new_plane_state->crtc_h, &i, false);
 	}
 
-	if (i > DC_MAX_DIRTY_RECTS)
-		goto ffu;
-
 	flip_addrs->dirty_rect_count = i;
 	return;