[PATCH v2] wifi: mt76: mt7915: Fix null-ptr-deref in mt7915_mmio_wed_init()

[PATCH v2] wifi: mt76: mt7915: Fix null-ptr-deref in mt7915_mmio_wed_init()

[Henry Martin]

devm_ioremap() returns NULL on error. Currently, mt7915_mmio_wed_init()
does not check for this case, which results in a NULL pointer
dereference.

Prevent null pointer dereference in mt7915_mmio_wed_init().

Fixes: 4f831d18d12d ("wifi: mt76: mt7915: enable WED RX support")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
V1 -> V2: Add a blank line after each test and correct commit message.

 drivers/net/wireless/mediatek/mt76/mt7915/mmio.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c b/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
index 876f0692850a..9c4d5cea0c42 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
@@ -651,6 +651,9 @@ int mt7915_mmio_wed_init(struct mt7915_dev *dev, void *pdev_ptr,
 		wed->wlan.base = devm_ioremap(dev->mt76.dev,
 					      pci_resource_start(pci_dev, 0),
 					      pci_resource_len(pci_dev, 0));
+		if (!wed->wlan.base)
+			return -ENOMEM;
+
 		wed->wlan.phy_base = pci_resource_start(pci_dev, 0);
 		wed->wlan.wpdma_int = pci_resource_start(pci_dev, 0) +
 				      MT_INT_WED_SOURCE_CSR;
@@ -678,6 +681,9 @@ int mt7915_mmio_wed_init(struct mt7915_dev *dev, void *pdev_ptr,
 		wed->wlan.bus_type = MTK_WED_BUS_AXI;
 		wed->wlan.base = devm_ioremap(dev->mt76.dev, res->start,
 					      resource_size(res));
+		if (!wed->wlan.base)
+			return -ENOMEM;
+
 		wed->wlan.phy_base = res->start;
 		wed->wlan.wpdma_int = res->start + MT_INT_SOURCE_CSR;
 		wed->wlan.wpdma_mask = res->start + MT_INT_MASK_CSR;
-- 
2.34.1

Re: [PATCH v2] wifi: mt76: mt7915: Fix null-ptr-deref in mt7915_mmio_wed_init()

[Markus Elfring]

…
> Prevent null pointer dereference in mt7915_mmio_wed_init().

Can any other summary phrase variant become more desirable accordingly?


…
> +++ b/drivers/net/wireless/mediatek/mt76/mt7915/mmio.c
…
> @@ -678,6 +681,9 @@ int mt7915_mmio_wed_init(struct mt7915_dev *dev, void *pdev_ptr,
>  		wed->wlan.bus_type = MTK_WED_BUS_AXI;
>  		wed->wlan.base = devm_ioremap(dev->mt76.dev, res->start,
>  					      resource_size(res));
> +		if (!wed->wlan.base)
> +			return -ENOMEM;
> +
…

Would the function “devm_platform_get_and_ioremap_resource” be applicable
in this else branch?
https://elixir.bootlin.com/linux/v6.14-rc6/source/drivers/base/platform.c#L87

Regards,
Markus