Skip to contentSkip to conversation

mtd: rawnand: atmel: Fix potential NULL pointer dereference

PATCH Superseded Gustavo A. R. Silva 2 participants 3 messages Sep 18, 2018

Subsystems (4)
Memory technology devices (MTD) Arm/Microchip (AT91) SoC support NAND flash Microchip NAND driver

v1 of 2 Superseded Latest is v2 →

lore
Share & tools
lore

Gustavo A. R. Silva

author
#0 lore raw

PATCH 1/1 mtd: rawnand: atmel: Fix potential NULL pointer dereference

There is a potential execution path in which function of_find_compatible_node() returns NULL. In such a case, we end up having a NULL pointer dereference when accessing pointer *nfc_np* in function of_clk_get().

So, we better don't take any chances and fix this by null checking pointer *nfc_np* before calling of_clk_get().

Addresses-Coverity-ID: 1473052 ("Dereference null return value")

Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/mtd/nand/raw/atmel/nand-controller.c | 5 +++++
 1 file changed, 5 insertions(+)
drivers/mtd/nand/raw/atmel/nand-controller.c +5 -0
index a38633a..ffa0c6b6 100644
@@ -2035,6 +2035,11 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nfc_np = of_find_compatible_node(dev->of_node, NULL,
 					 "atmel,sama5d3-nfc");
 
+	if (!nfc_np) {
+		dev_err(dev, "Could not find device node for sama5d3-nfc\n");
+		return -ENODEV;
+	}
+
 	nc->clk = of_clk_get(nfc_np, 0);
 	if (IS_ERR(nc->clk)) {
 		ret = PTR_ERR(nc->clk);
Signature · 1 line
2.7.4
#1 lore raw

Hi Gustavo,

Quoted 9 lines · On Tue, 18 Sep 2018 08:33:17 -0500 "Gustavo A. R. Silva"…

There is a potential execution path in which function of_find_compatible_node() returns NULL. In such a case, we end up having a NULL pointer dereference when accessing pointer *nfc_np* in function of_clk_get().

So, we better don't take any chances and fix this by null checking pointer *nfc_np* before calling of_clk_get().

Addresses-Coverity-ID: 1473052 ("Dereference null return value")

Can you add a Fixes tag here?

drivers/mtd/nand/raw/atmel/nand-controller.c atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc) · line 2037

Quoted 13 lines
Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/mtd/nand/raw/atmel/nand-controller.c | 5 +++++
 1 file changed, 5 insertions(+)
drivers/mtd/nand/raw/atmel/nand-controller.c +0 -0
index a38633a..ffa0c6b6 100644
@@ -2035,6 +2035,11 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nfc_np = of_find_compatible_node(dev->of_node, NULL,
 					 "atmel,sama5d3-nfc");

Can you drop this blank line?

drivers/mtd/nand/raw/atmel/nand-controller.c atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc) · line 2045

Quoted 8 lines
drivers/mtd/nand/raw/atmel/nand-controller.c +5 -0
+	if (!nfc_np) {
+		dev_err(dev, "Could not find device node for sama5d3-nfc\n");
+		return -ENODEV;
+	}
+
 	nc->clk = of_clk_get(nfc_np, 0);
 	if (IS_ERR(nc->clk)) {
 		ret = PTR_ERR(nc->clk);

Thanks,

Boris

author
#2 lore raw

Hi Boris,

Quoted 10 lines · Boris Brezillon

Hi Gustavo,

Quoted 5 lines · On Tue, 18 Sep 2018 08:33:17 -0500 "Gustavo A. R. Silva"…

There is a potential execution path in which function of_find_compatible_node() returns NULL. In such a case, we end up having a NULL pointer dereference when accessing pointer *nfc_np* in function of_clk_get().

Quoted 7 lines
Quoted 4 lines

So, we better don't take any chances and fix this by null checking pointer *nfc_np* before calling of_clk_get().

Addresses-Coverity-ID: 1473052 ("Dereference null return value")

Can you add a Fixes tag here?

Yep.

Quoted 5 lines
Quoted 5 lines
Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/mtd/nand/raw/atmel/nand-controller.c | 5 +++++
 1 file changed, 5 insertions(+)
Quoted 11 lines

drivers/mtd/nand/raw/atmel/nand-controller.c atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc) · line 2037

Quoted 8 lines
drivers/mtd/nand/raw/atmel/nand-controller.c +0 -0
index a38633a..ffa0c6b6 100644
@@ -2035,6 +2035,11 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nfc_np = of_find_compatible_node(dev->of_node, NULL,
 					 "atmel,sama5d3-nfc");

Can you drop this blank line?

OK. Sure thing.

I'll send v2 shortly.

Thanks for the feedback.
--
Gustavo