[PATCH] wifi: wilc1000: use vmm_table as array in wilc struct

[Alexis Lothoré]

From: Ajay Singh <ajay.kathat@xxxxxxxxxxxxx>

Enabling KASAN and running some iperf tests raises some memory issues with
vmm_table:

BUG: KASAN: slab-out-of-bounds in wilc_wlan_handle_txq+0x6ac/0xdb4
Write of size 4 at addr c3a61540 by task wlan0-tx/95

KASAN detects that we are writing data beyond range allocated to vmm_table.
There is indeed a mismatch between the size passed to allocator in
wilc_wlan_init, and the range of possible indexes used later: allocation
size is missing a multiplication by sizeof(u32)

While at it, instead of simply multiplying the allocation size, do not keep
dedicated dynamic allocation for vmm_table: define it as an array with the
relevant size in wilc struct, which is already dynamically allocated

Fixes: 40b717bfcefa ("wifi: wilc1000: fix DMA on stack objects")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ajay Singh <ajay.kathat@xxxxxxxxxxxxx>
Signed-off-by: Alexis Lothoré <alexis.lothore@xxxxxxxxxxx>
---
 drivers/net/wireless/microchip/wilc1000/netdev.h |  2 +-
 drivers/net/wireless/microchip/wilc1000/wlan.c   | 12 ------------
 2 files changed, 1 insertion(+), 13 deletions(-)

diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.h b/drivers/net/wireless/microchip/wilc1000/netdev.h
index bb1a315a7b7e..2137ef294953 100644
--- a/drivers/net/wireless/microchip/wilc1000/netdev.h
+++ b/drivers/net/wireless/microchip/wilc1000/netdev.h
@@ -245,7 +245,7 @@ struct wilc {
 	u8 *rx_buffer;
 	u32 rx_buffer_offset;
 	u8 *tx_buffer;
-	u32 *vmm_table;
+	u32 vmm_table[WILC_VMM_TBL_SIZE];
 
 	struct txq_handle txq[NQUEUES];
 	int txq_entries;
diff --git a/drivers/net/wireless/microchip/wilc1000/wlan.c b/drivers/net/wireless/microchip/wilc1000/wlan.c
index 58bbf50081e4..d93493c40e49 100644
--- a/drivers/net/wireless/microchip/wilc1000/wlan.c
+++ b/drivers/net/wireless/microchip/wilc1000/wlan.c
@@ -1252,8 +1252,6 @@ void wilc_wlan_cleanup(struct net_device *dev)
 	while ((rqe = wilc_wlan_rxq_remove(wilc)))
 		kfree(rqe);
 
-	kfree(wilc->vmm_table);
-	wilc->vmm_table = NULL;
 	kfree(wilc->rx_buffer);
 	wilc->rx_buffer = NULL;
 	kfree(wilc->tx_buffer);
@@ -1491,14 +1489,6 @@ int wilc_wlan_init(struct net_device *dev)
 			goto fail;
 	}
 
-	if (!wilc->vmm_table)
-		wilc->vmm_table = kzalloc(WILC_VMM_TBL_SIZE, GFP_KERNEL);
-
-	if (!wilc->vmm_table) {
-		ret = -ENOBUFS;
-		goto fail;
-	}
-
 	if (!wilc->tx_buffer)
 		wilc->tx_buffer = kmalloc(WILC_TX_BUFF_SIZE, GFP_KERNEL);
 
@@ -1523,8 +1513,6 @@ int wilc_wlan_init(struct net_device *dev)
 	return 0;
 
 fail:
-	kfree(wilc->vmm_table);
-	wilc->vmm_table = NULL;
 	kfree(wilc->rx_buffer);
 	wilc->rx_buffer = NULL;
 	kfree(wilc->tx_buffer);

---
base-commit: f28d2198de8cbefa17286d5182337a1d6d518643
change-id: 20231012-wilc1000_tx_oops-58ce91ee3e93

Best regards,
-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com