Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35;
Date:   Thu, 05 Oct 2023 01:29:45 +0000
Mime-Version: 1.0
Message-ID: <20231005-strncpy-drivers-net-ethernet-atheros-atlx-atl2-c-v1-1-493f113ebfc7@google.com>
Subject: [PATCH] net: atheros: replace deprecated strncpy with strscpy
From:   Justin Stitt <justinstitt@google.com>
To:     Chris Snook <chris.snook@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org,
        Justin Stitt <justinstitt@google.com>
Content-Type: text/plain; charset="utf-8"
Precedence: bulk

`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@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.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@google.com>