strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces.
Based on usage part_str usage within txgbe_read_pba_string(), we expect part_str to be NUL-terminated but not necessarily NUL-padded: | /* put a null character on the end of our string */ | pba_num[10] = '\0'; Interestingly, part_str is not used after txgbe_read_pba_string(): | ... | err = txgbe_read_pba_string(wx, part_str, TXGBE_PBANUM_LENGTH); | if (err) | strscpy(part_str, "Unknown", sizeof(part_str)); | | netif_info(wx, probe, netdev, "%pM\n", netdev->dev_addr); | | return 0; | |err_remove_phy: | txgbe_remove_phy(txgbe); |err_release_hw: | wx_clear_interrupt_scheme(wx); | wx_control_hw(wx, false); |err_free_mac_table: | kfree(wx->mac_table); |err_pci_release_regions: | pci_release_selected_regions(pdev, | pci_select_bars(pdev, IORESOURCE_MEM)); |err_pci_disable_dev: | pci_disable_device(pdev); | return err; |} ... this means this strncpy (or now strscpy) is probably useless. For now, let's make the swap to strscpy() as I am not sure if this is truly dead code or not. 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 <justinst...@google.com> --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/ethernet/wangxun/txgbe/txgbe_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c index 5c3aed516ac2..c795fbab37be 100644 --- a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c +++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c @@ -739,7 +739,7 @@ static int txgbe_probe(struct pci_dev *pdev, /* First try to read PBA as a string */ err = txgbe_read_pba_string(wx, part_str, TXGBE_PBANUM_LENGTH); if (err) - strncpy(part_str, "Unknown", TXGBE_PBANUM_LENGTH); + strscpy(part_str, "Unknown", sizeof(part_str)); netif_info(wx, probe, netdev, "%pM\n", netdev->dev_addr); --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231012-strncpy-drivers-net-ethernet-wangxun-txgbe-txgbe_main-c-05152bafac20 Best regards, -- Justin Stitt <justinst...@google.com>
