[PATCH 5.9 19/49] net: ll_temac: Fix potential NULL dereference in temac_probe()

From: Greg Kroah-Hartman
Date: Sat Dec 19 2020 - 08:07:09 EST


From: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>

[ Upstream commit cc6596fc7295e9dcd78156ed42f9f8e1221f7530 ]

platform_get_resource() may fail and in this case a NULL dereference
will occur.

Fix it to use devm_platform_ioremap_resource() instead of calling
platform_get_resource() and devm_ioremap().

This is detected by Coccinelle semantic patch.

@@
expression pdev, res, n, t, e, e1, e2;
@@

res = \(platform_get_resource\|platform_get_resource_byname\)(pdev, t, n);
+ if (!res)
+ return -EINVAL;
... when != res == NULL
e = devm_ioremap(e1, res->start, e2);

Fixes: 8425c41d1ef7 ("net: ll_temac: Extend support to non-device-tree platforms")
Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>
Acked-by: Esben Haabendal <esben@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/xilinx/ll_temac_main.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -1351,7 +1351,6 @@ static int temac_probe(struct platform_d
struct device_node *temac_np = dev_of_node(&pdev->dev), *dma_np;
struct temac_local *lp;
struct net_device *ndev;
- struct resource *res;
const void *addr;
__be32 *p;
bool little_endian;
@@ -1500,13 +1499,11 @@ static int temac_probe(struct platform_d
of_node_put(dma_np);
} else if (pdata) {
/* 2nd memory resource specifies DMA registers */
- res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
- lp->sdma_regs = devm_ioremap(&pdev->dev, res->start,
- resource_size(res));
- if (!lp->sdma_regs) {
+ lp->sdma_regs = devm_platform_ioremap_resource(pdev, 1);
+ if (IS_ERR(lp->sdma_regs)) {
dev_err(&pdev->dev,
"could not map DMA registers\n");
- return -ENOMEM;
+ return PTR_ERR(lp->sdma_regs);
}
if (pdata->dma_little_endian) {
lp->dma_in = temac_dma_in32_le;