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mtd: rawnand: atmel: Fix potential NULL pointer dereference

PATCH Applied Gustavo A. R. Silva 4 participants 4 messages Sep 18, 2018 – Sep 19, 2018

Subsystems (4)
Memory technology devices (MTD) Arm/Microchip (AT91) SoC support NAND flash Microchip NAND driver
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Gustavo A. R. Silva

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#0 lore raw

PATCH v2 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")

Fixes f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by Gustavo A. R. Silva <[email protected]>

---
Changes in v2:
- Add Fixes tag to the commit log.
- Remove blank line before null checking nfc_np.

 drivers/mtd/nand/raw/atmel/nand-controller.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/mtd/nand/raw/atmel/nand-controller.c +4 -0
index a38633a..5bfbe97 100644
@@ -2034,6 +2034,10 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nand_np = dev->of_node;
 	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)) {
Signature · 1 line
2.7.4
Reviewed-by on v2 1/1
#1 lore raw
Quoted 11 lines · On Tue, 18 Sep 2018 08:55:55 -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")

Fixes f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by Gustavo A. R. Silva <[email protected]>
Reviewed-by Boris Brezillon <[email protected]>
Quoted 23 lines

---
Changes in v2:
- Add Fixes tag to the commit log.
- Remove blank line before null checking nfc_np.

 drivers/mtd/nand/raw/atmel/nand-controller.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/mtd/nand/raw/atmel/nand-controller.c +4 -0
index a38633a..5bfbe97 100644
@@ -2034,6 +2034,10 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nand_np = dev->of_node;
 	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)) {
Acked-by on v2 1/1
#2 lore raw
In reply to Gustavo A. R. Silva
Quoted 11 lines · 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")

Fixes f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by Gustavo A. R. Silva <[email protected]>
Acked-by Tudor Ambarus <[email protected]>
Quoted 24 lines

---
Changes in v2:
- Add Fixes tag to the commit log.
- Remove blank line before null checking nfc_np.

 drivers/mtd/nand/raw/atmel/nand-controller.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/mtd/nand/raw/atmel/nand-controller.c +4 -0
index a38633a..5bfbe97 100644
@@ -2034,6 +2034,10 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nand_np = dev->of_node;
 	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)) {
maintainer Applied
#3 lore raw
In reply to Gustavo A. R. Silva

Hi Gustavo,

"Gustavo A. R. Silva" <[email protected]> wrote on Tue, 18 Sep 2018 08:55:55 -0500:

Quoted 5 lines

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

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")

Fixes f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by Gustavo A. R. Silva <[email protected]>

---

Applied to nand/next.

Thanks,
Miqu?l