[PATCH 6.12.y 2/2] drm/sysfb: simpledrm: Improve framebuffer-size validation

[Sasha Levin <sashal@kernel.org>]

From: Thomas Zimmermann <tzimmermann@suse.de>

[ Upstream commit 03f1a3545b721fa7fdadd00080e237519a286a97 ]

Validate the framebuffer size from the firmware against the
limitations of struct drm_display_mode. The type only stores sizes
in 16-bit fields. Fail probing on errors.

v2:
- remove unused function simplefb_get_validated_int0() (Sashiko)

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: 11e8f5fd223b ("drm: Add simpledrm driver")
Cc: <stable@vger.kernel.org> # v5.14+
Fixes: 11e8f5fd223b ("drm: Add simpledrm driver")
Link: https://patch.msgid.link/20260625094509.157581-2-tzimmermann@suse.de
[ adapted shared-validator changes to the existing simplefb_get_validated_int0() helper in drm/tiny/simpledrm.c. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/tiny/simpledrm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 07abaf27315f7..b5df36aea6575 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -54,7 +54,7 @@ static int
 simplefb_get_validated_int0(struct drm_device *dev, const char *name,
 			    uint32_t value)
 {
-	if (!value) {
+	if (!value || value > U16_MAX) {
 		drm_err(dev, "simplefb: invalid framebuffer %s of %u\n",
 			name, value);
 		return -EINVAL;
-- 
2.53.0