[PATCH] drm/ast: validate framebuffer VRAM size in ast_mode.c and DP501 firmware bounds

[PATCH] drm/ast: validate framebuffer VRAM size in ast_mode.c and DP501 firmware bounds

[Hui Peng]

In drivers/gpu/drm/ast/ (ast_mode.c, ast_dp501.c), verify that the
primary plane framebuffer fits within ast->vram_size and bounds-check
DP501 firmware headers.

Fixes: 312fec1405dd ("drm: Initial KMS driver for AST (ASpeed Technologies) 2000 series (v2)")
Assisted-by: LLM
Signed-off-by: Hui Peng <benquike@gmail.com>
---
diff --git a/drivers/gpu/drm/ast/ast_dp501.c b/drivers/gpu/drm/ast/ast_dp501.c
index 6d6ccfad1415..d9ca8760e5b5 100644
--- a/drivers/gpu/drm/ast/ast_dp501.c
+++ b/drivers/gpu/drm/ast/ast_dp501.c
@@ -250,7 +250,8 @@ static bool ast_launch_m68k(struct ast_device *ast)
 
 		/* copy image to buffer */
 		for (i = 0; i < len; i += 4) {
-			data = *(u32 *)(fw_addr + i);
+			data = 0;
+			memcpy(&data, fw_addr + i, min_t(u32, len - i, 4));
 			ast_moutdwm(ast, boot_address + i, data);
 		}
 
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index d5ed8c5c7925..bde9dcbbc32b 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -510,6 +510,7 @@ static int ast_primary_plane_helper_atomic_check(struct drm_plane *plane,
 						 struct drm_atomic_commit *state)
 {
 	struct drm_device *dev = plane->dev;
+	struct ast_plane *ast_plane = to_ast_plane(plane);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_crtc_state *new_crtc_state = NULL;
 	struct ast_crtc_state *new_ast_crtc_state;
@@ -531,6 +532,11 @@ static int ast_primary_plane_helper_atomic_check(struct drm_plane *plane,
 			return 0;
 	}
 
+	if (new_plane_state->fb->pitches[0] > AST_PRIMARY_PLANE_MAX_OFFSET)
+		return -EINVAL;
+	if ((u64)new_plane_state->fb->pitches[0] * new_plane_state->fb->height > ast_plane->size)
+		return -ENOSPC;
+
 	new_ast_crtc_state = to_ast_crtc_state(new_crtc_state);
 
 	new_ast_crtc_state->format = new_plane_state->fb->format;