queue-6.1/drm-sysfb-simpledrm-improve-stride-validation.patch

From 9a04ce0c203db9341ca2f28c0075e49dd73bcaee Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Sat, 12 Sep 2026 11:39:50 -0400
Subject: drm/sysfb: simpledrm: Improve stride validation

From: Thomas Zimmermann <tzimmermann@suse.de>

[ Upstream commit df6533f11688aa30be3bb883c7637f4ffdbb7cbd ]

Validate the computed stride against the maximum value INT_MAX.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Fixes: 7bfa5c7b28d6 ("drm/simpledrm: Compute linestride with drm_format_info_min_pitch()")
Cc: <stable@vger.kernel.org> # v6.1+
Link: https://patch.msgid.link/20260625094509.157581-5-tzimmermann@suse.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/tiny/simpledrm.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 18489779fb8aa..4b5ccbb13ecfe 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -693,9 +693,15 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
 		return ERR_PTR(-ENODEV);
 	}
 	if (!stride) {
-		stride = drm_format_info_min_pitch(format, 0, width);
-		if (drm_WARN_ON(dev, !stride))
+		u64 pitch = drm_format_info_min_pitch(format, 0, width);
+
+		if (drm_WARN_ON(dev, !pitch)) {
+			return ERR_PTR(-EINVAL); /* driver bug */
+		} else if (pitch > INT_MAX) {
+			drm_warn(dev, "stride of %llu exceeds maximum\n", pitch);
 			return ERR_PTR(-EINVAL);
+		}
+		stride = pitch;
 	}
 
 	sdev->mode = simpledrm_mode(width, height);
-- 
2.53.0