Cell-index value is obtained from Device Tree and then used to calculate
the index for accessing arrays port_mfl[], mac_mfl[] and intr_mng[].
In case of broken DT due to any error cell-index can contain any value
and it is possible to go beyond the array boundaries which can lead
at least to memory corruption.

Validate cell-index value obtained from Device Tree.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 414fd46e7762 ("fsl/fman: Add FMan support")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
---
v3:
  - Add Reviewed-by: Sean Anderson <sean.anderson@seco.com>
    (https://lore.kernel.org/all/e0b8c69a-3cc0-4034-b3f7-d8bdcc480c4d@seco.com/)
v2: https://lore.kernel.org/all/20240702140124.19096-1-amishin@t-argos.ru/
  - Move check to mac.c to avoid allmodconfig build errors and reference leaks
v1: https://lore.kernel.org/all/20240702095034.12371-1-amishin@t-argos.ru/

 drivers/net/ethernet/freescale/fman/fman.c | 1 -
 drivers/net/ethernet/freescale/fman/fman.h | 3 +++
 drivers/net/ethernet/freescale/fman/mac.c  | 4 ++++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fman/fman.c b/drivers/net/ethernet/freescale/fman/fman.c
index d96028f01770..fb416d60dcd7 100644
--- a/drivers/net/ethernet/freescale/fman/fman.c
+++ b/drivers/net/ethernet/freescale/fman/fman.c
@@ -24,7 +24,6 @@
 
 /* General defines */
 #define FMAN_LIODN_TBL			64	/* size of LIODN table */
-#define MAX_NUM_OF_MACS			10
 #define FM_NUM_OF_FMAN_CTRL_EVENT_REGS	4
 #define BASE_RX_PORTID			0x08
 #define BASE_TX_PORTID			0x28
diff --git a/drivers/net/ethernet/freescale/fman/fman.h b/drivers/net/ethernet/freescale/fman/fman.h
index 2ea575a46675..74eb62eba0d7 100644
--- a/drivers/net/ethernet/freescale/fman/fman.h
+++ b/drivers/net/ethernet/freescale/fman/fman.h
@@ -74,6 +74,9 @@
 #define BM_MAX_NUM_OF_POOLS		64 /* Buffers pools */
 #define FMAN_PORT_MAX_EXT_POOLS_NUM	8  /* External BM pools per Rx port */
 
+/* General defines */
+#define MAX_NUM_OF_MACS			10
+
 struct fman; /* FMan data */
 
 /* Enum for defining port types */
diff --git a/drivers/net/ethernet/freescale/fman/mac.c b/drivers/net/ethernet/freescale/fman/mac.c
index 9767586b4eb3..ac9ad5e67b44 100644
--- a/drivers/net/ethernet/freescale/fman/mac.c
+++ b/drivers/net/ethernet/freescale/fman/mac.c
@@ -247,6 +247,10 @@ static int mac_probe(struct platform_device *_of_dev)
 		dev_err(dev, "failed to read cell-index for %pOF\n", mac_node);
 		return -EINVAL;
 	}
+	if (val >= MAX_NUM_OF_MACS) {
+		dev_err(dev, "cell-index value is too big for %pOF\n", mac_node);
+		return -EINVAL;
+	}
 	priv->cell_index = (u8)val;
 
 	/* Get the MAC address */
-- 
2.30.2

On Wed, 4 Sep 2024 09:09:20 +0300 Aleksandr Mishin wrote:
> Cell-index value is obtained from Device Tree and then used to calculate
> the index for accessing arrays port_mfl[], mac_mfl[] and intr_mng[].
> In case of broken DT due to any error cell-index can contain any value
> and it is possible to go beyond the array boundaries which can lead
> at least to memory corruption.
> 
> Validate cell-index value obtained from Device Tree.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.

coccicheck complains of_dev is not released, we should fix that first,
before we add more returns here.
-- 
pw-bot: cr