| Message ID | 20231010-strncpy-drivers-net-ethernet-intel-igb-igb_main-c-v1-1-d796234a8abf@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | igb: replace deprecated strncpy with strscpy | expand |
On 10/10/2023 2:07 PM, Justin Stitt wrote: > `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. Please see my comments on the igbvf patch.
On Tue, Oct 10, 2023 at 09:07:59PM +0000, Justin Stitt wrote: > `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(-) > > 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); > > --- > base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 > change-id: 20231010-strncpy-drivers-net-ethernet-intel-igb-igb_main-c-b259e3f289d3 > > Best regards, > -- > Justin Stitt <justinstitt@google.com> > Hi, this patch was bundled up with some others. It has a new home: https://lore.kernel.org/all/20231010-netdev-replace-strncpy-resend-as-series-v1-0-caf9f0f2f021@google.com/
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(-) --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231010-strncpy-drivers-net-ethernet-intel-igb-igb_main-c-b259e3f289d3 Best regards, -- Justin Stitt <justinstitt@google.com>