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From:   Paul Kocialkowski <paul.kocialkowski@bootlin.com>
To:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Cc:     Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Maxime Ripard <mripard@kernel.org>,
        Dan Carpenter <dan.carpenter@oracle.com>
Subject: [PATCH 1/2] drm/logicvc: Avoid possible overflow in layer buffer setup variables
Date:   Wed, 25 Oct 2023 15:09:45 +0200
Message-ID: <20231025130946.119957-1-paul.kocialkowski@bootlin.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The buffer_sel, voffset and hoffset values are calculated from u32
values and might overflow under certain conditions.

Move them to u32 definitions instead of u8/u16 to avoid the issue.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: efeeaefe9be5 ("drm: Add support for the LogiCVC display controller")
---
 drivers/gpu/drm/logicvc/logicvc_layer.c | 6 +++---
 drivers/gpu/drm/logicvc/logicvc_layer.h | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/logicvc/logicvc_layer.c b/drivers/gpu/drm/logicvc/logicvc_layer.c
index 464000aea765..eea22379d042 100644
--- a/drivers/gpu/drm/logicvc/logicvc_layer.c
+++ b/drivers/gpu/drm/logicvc/logicvc_layer.c
@@ -268,9 +268,9 @@ int logicvc_layer_buffer_find_setup(struct logicvc_drm *logicvc,
 	u32 layer_stride = layer_bytespp * logicvc->config.row_stride;
 	u32 base_offset = layer->config.base_offset * layer_stride;
 	u32 buffer_offset = layer->config.buffer_offset * layer_stride;
-	u8 buffer_sel = 0;
-	u16 voffset = 0;
-	u16 hoffset = 0;
+	u32 buffer_sel = 0;
+	u32 voffset = 0;
+	u32 hoffset = 0;
 	phys_addr_t fb_addr;
 	u32 fb_offset;
 	u32 gap;
diff --git a/drivers/gpu/drm/logicvc/logicvc_layer.h b/drivers/gpu/drm/logicvc/logicvc_layer.h
index 4a4b02e9b819..a06feeda3abf 100644
--- a/drivers/gpu/drm/logicvc/logicvc_layer.h
+++ b/drivers/gpu/drm/logicvc/logicvc_layer.h
@@ -18,9 +18,9 @@
 #define LOGICVC_LAYER_ALPHA_PIXEL		1
 
 struct logicvc_layer_buffer_setup {
-	u8 buffer_sel;
-	u16 voffset;
-	u16 hoffset;
+	u32 buffer_sel;
+	u32 voffset;
+	u32 hoffset;
 };
 
 struct logicvc_layer_config {
-- 
2.42.0