| Message ID | 20231010-netdev-replace-strncpy-resend-as-series-v1-5-caf9f0f2f021@google.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: intel: replace deprecated strncpy uses | expand |
> -----Original Message----- > From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of Justin Stitt > Sent: Wednesday, October 11, 2023 3:57 AM > To: Brandeburg, Jesse <jesse.brandeburg@intel.com>; Nguyen, Anthony L <anthony.l.nguyen@intel.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; Justin Stitt <justinstitt@google.com>; intel-wired-lan@lists.osuosl.org; linux-hardening@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: [Intel-wired-lan] [PATCH v1 net-next 5/7] igb: 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 see that netdev->name is expected to be NUL-terminated based on its > usage with format strings: > | sprintf(q_vector->name, "%s-TxRx-%u", netdev->name, > | q_vector->rx.ring->queue_index); > > Furthermore, NUL-padding is not required as netdev is already > zero-allocated: > | netdev = alloc_etherdev_mq(sizeof(struct igb_adapter), > | IGB_MAX_TX_QUEUES); > ... > alloc_etherdev_mq() -> alloc_etherdev_mqs() -> alloc_netdev_mqs() ... > | p = kvzalloc(alloc_size, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); > > 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/intel/igb/igb_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 76b34cee1da3..9de103bd3ad3 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -3264,7 +3264,7 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent) igb_set_ethtool_ops(netdev); netdev->watchdog_timeo = 5 * HZ; - strncpy(netdev->name, pci_name(pdev), sizeof(netdev->name) - 1); + strscpy(netdev->name, pci_name(pdev), sizeof(netdev->name)); netdev->mem_start = pci_resource_start(pdev, 0); netdev->mem_end = pci_resource_end(pdev, 0);
`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 see that netdev->name is expected to be NUL-terminated based on its usage with format strings: | sprintf(q_vector->name, "%s-TxRx-%u", netdev->name, | q_vector->rx.ring->queue_index); Furthermore, NUL-padding is not required as netdev is already zero-allocated: | netdev = alloc_etherdev_mq(sizeof(struct igb_adapter), | IGB_MAX_TX_QUEUES); ... alloc_etherdev_mq() -> alloc_etherdev_mqs() -> alloc_netdev_mqs() ... | p = kvzalloc(alloc_size, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); 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/intel/igb/igb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)