6.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
[ Upstream commit d761b9450e31e5abd212f0085d424ed32760de5a ]
CERT-C Characters and Strings (CERT STR31-C)
all_drm_priv[cnt] evaluates to an address that could be at negative
offset of an array.
In mtk_drm_get_all_drm_priv():
Guarantee that storage for strings has sufficient space for character
data and the null terminator.
So change cnt to unsigned int and check its max value.
Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>
Reviewed-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20230714094908.13087-3-jason-jh.lin@xxxxxxxxxxxx/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_drm_drv.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 6dcb4ba2466c0..fc217e0acd45d 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -354,7 +354,7 @@ static bool mtk_drm_get_all_drm_priv(struct device *dev)
const struct of_device_id *of_id;
struct device_node *node;
struct device *drm_dev;
- int cnt = 0;
+ unsigned int cnt = 0;
int i, j;
for_each_child_of_node(phandle->parent, node) {
@@ -375,6 +375,9 @@ static bool mtk_drm_get_all_drm_priv(struct device *dev)
all_drm_priv[cnt] = dev_get_drvdata(drm_dev);
if (all_drm_priv[cnt] && all_drm_priv[cnt]->mtk_drm_bound)
cnt++;
+
+ if (cnt == MAX_CRTC)
+ break;
}
if (drm_priv->data->mmsys_dev_num == cnt) {
--
2.40.1
