linux-hardening - [PATCH] net: atheros: replace deprecated strncpy with strscpy

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Date: Thu, 05 Oct 2023 01:29:45 +0000
From: Justin Stitt <justinstitt@...gle.com>
To: Chris Snook <chris.snook@...il.com>, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-hardening@...r.kernel.org, Justin Stitt <justinstitt@...gle.com>
Subject: [PATCH] net: atheros: replace deprecated strncpy with strscpy

`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

We expect netdev->name to be NUL-terminated based on its use with format
strings and dev_info():
|     dev_info(&adapter->pdev->dev,
|             "%s link is up %d Mbps %s\n",
|             netdev->name, adapter->link_speed,
|             adapter->link_duplex == FULL_DUPLEX ?
|             "full duplex" : "half duplex");

Furthermore, NUL-padding is not required as netdev is already
zero-initialized through alloc_etherdev().

Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@...r.kernel.org
Signed-off-by: Justin Stitt <justinstitt@...gle.com>
---
Note: build-tested only.
---
 drivers/net/ethernet/atheros/atlx/atl2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/atheros/atlx/atl2.c b/drivers/net/ethernet/atheros/atlx/atl2.c
index 1b487c071cb6..bcfc9488125b 100644
--- a/drivers/net/ethernet/atheros/atlx/atl2.c
+++ b/drivers/net/ethernet/atheros/atlx/atl2.c
@@ -1377,7 +1377,7 @@ static int atl2_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	netdev->watchdog_timeo = 5 * HZ;
 	netdev->min_mtu = 40;
 	netdev->max_mtu = ETH_DATA_LEN + VLAN_HLEN;
-	strncpy(netdev->name, pci_name(pdev), sizeof(netdev->name) - 1);
+	strscpy(netdev->name, pci_name(pdev), sizeof(netdev->name));
 
 	netdev->mem_start = mmio_start;
 	netdev->mem_end = mmio_start + mmio_len;

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231005-strncpy-drivers-net-ethernet-atheros-atlx-atl2-c-d876945d6341

Best regards,
--
Justin Stitt <justinstitt@...gle.com>