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Subject[PATCH v3 5/7] iommu/mediatek: Validate number of phandles associated with "mediatek,larbs"
Date
From: Guenter Roeck <groeck@chromium.org>

Fix the smatch warnings:
drivers/iommu/mtk_iommu.c:878 mtk_iommu_mm_dts_parse() error: uninitialized
symbol 'larbnode'.

If someone abuse the dtsi node(Don't follow the definition of dt-binding),
for example "mediatek,larbs" is provided as boolean property, "larb_nr"
will be zero and cause abnormal.

To fix this problem and improve the code safety, add some checking
for the invalid input from dtsi, e.g. checking the larb_nr/larbid valid
range, and avoid "mediatek,larb-id" property conflicts in the smi-larb
nodes.

Fixes: d2e9a1102cfc ("iommu/mediatek: Contain MM IOMMU flow with the MM TYPE")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
drivers/iommu/mtk_iommu.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index aa0973bafde1..88d0dad36067 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1052,6 +1052,8 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
larb_nr = of_count_phandle_with_args(dev->of_node, "mediatek,larbs", NULL);
if (larb_nr < 0)
return larb_nr;
+ if (larb_nr == 0 || larb_nr > MTK_LARB_NR_MAX)
+ return -EINVAL;

for (i = 0; i < larb_nr; i++) {
u32 id;
@@ -1070,6 +1072,11 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
ret = of_property_read_u32(larbnode, "mediatek,larb-id", &id);
if (ret)/* The id is consecutive if there is no this property */
id = i;
+ if (id >= MTK_LARB_NR_MAX) {
+ of_node_put(larbnode);
+ ret = -EINVAL;
+ goto err_larbdev_put;
+ }

plarbdev = of_find_device_by_node(larbnode);
of_node_put(larbnode);
@@ -1077,6 +1084,11 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
ret = -ENODEV;
goto err_larbdev_put;
}
+ if (data->larb_imu[id].dev) {
+ platform_device_put(plarbdev);
+ ret = -EEXIST;
+ goto err_larbdev_put;
+ }
data->larb_imu[id].dev = &plarbdev->dev;

if (!plarbdev->dev.driver) {
--
2.18.0
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