[PATCH] qlcnic: replace deprecated strncpy with strscpy

From: Justin Stitt <justinstitt@google.com>
To: Shahed Shaikh <shshaikh@marvell.com>,
	Manish Chopra <manishc@marvell.com>,
	GR-Linux-NIC-Dev@marvell.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>
Subject: [PATCH] qlcnic: replace deprecated strncpy with strscpy
Date: Thu, 12 Oct 2023 19:44:29 +0000	[thread overview]
Message-ID: <20231012-strncpy-drivers-net-ethernet-qlogic-qlcnic-qlcnic_83xx_init-c-v1-1-f0008d5e43be@google.com> (raw)

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 fw_info->fw_file_name to be NUL-terminated based on its use
within _request_firmware_prepare() wherein `name` refers to it:
|       if (firmware_request_builtin_buf(firmware, name, dbuf, size)) {
|               dev_dbg(device, "using built-in %s\n", name);
|               return 0; /* assigned */
|       }
... and with firmware_request_builtin() also via `name`:
|       if (strcmp(name, b_fw->name) == 0) {

There is no evidence that NUL-padding is required.

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.

Found with: $ rg "strncpy\("
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
index c95d56e56c59..b733374b4dc5 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
@@ -2092,8 +2092,8 @@ static int qlcnic_83xx_run_post(struct qlcnic_adapter *adapter)
 		return -EINVAL;
 	}
 
-	strncpy(fw_info->fw_file_name, QLC_83XX_POST_FW_FILE_NAME,
-		QLC_FW_FILE_NAME_LEN);
+	strscpy(fw_info->fw_file_name, QLC_83XX_POST_FW_FILE_NAME,
+		sizeof(fw_info->fw_file_name));
 
 	ret = request_firmware(&fw_info->fw, fw_info->fw_file_name, dev);
 	if (ret) {
@@ -2396,12 +2396,12 @@ static int qlcnic_83xx_get_fw_info(struct qlcnic_adapter *adapter)
 		switch (pdev->device) {
 		case PCI_DEVICE_ID_QLOGIC_QLE834X:
 		case PCI_DEVICE_ID_QLOGIC_QLE8830:
-			strncpy(fw_info->fw_file_name, QLC_83XX_FW_FILE_NAME,
-				QLC_FW_FILE_NAME_LEN);
+			strscpy(fw_info->fw_file_name, QLC_83XX_FW_FILE_NAME,
+				sizeof(fw_info->fw_file_name));
 			break;
 		case PCI_DEVICE_ID_QLOGIC_QLE844X:
-			strncpy(fw_info->fw_file_name, QLC_84XX_FW_FILE_NAME,
-				QLC_FW_FILE_NAME_LEN);
+			strscpy(fw_info->fw_file_name, QLC_84XX_FW_FILE_NAME,
+				sizeof(fw_info->fw_file_name));
 			break;
 		default:
 			dev_err(&pdev->dev, "%s: Invalid device id\n",

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231012-strncpy-drivers-net-ethernet-qlogic-qlcnic-qlcnic_83xx_init-c-7858019dc583

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

