> -----Original Message----- > From: Justin Stitt <justinst...@google.com> > Sent: Thursday, October 5, 2023 3:56 AM > To: Agroskin, Shay <shay...@amazon.com>; Kiyanovski, Arthur > <akiy...@amazon.com>; Arinzon, David <darin...@amazon.com>; Dagan, > Noam <nda...@amazon.com>; Bshara, Saeed <sae...@amazon.com>; David > S. Miller <da...@davemloft.net>; Eric Dumazet <eduma...@google.com>; > Jakub Kicinski <k...@kernel.org>; Paolo Abeni <pab...@redhat.com> > Cc: net...@vger.kernel.org; linux-ker...@vger.kernel.org; linux- > harden...@vger.kernel.org; Justin Stitt <justinst...@google.com> > Subject: [EXTERNAL] [PATCH] net: ena: replace deprecated strncpy with strscpy > > CAUTION: This email originated from outside of the organization. Do not click > links or open attachments unless you can confirm the sender and know the > content is safe. > > > > `strncpy` is deprecated for use on NUL-terminated destination strings [1] and > as > such we should prefer more robust and less ambiguous string interfaces. > > NUL-padding is not necessary as host_info is initialized to `ena_dev- > >host_attr.host_info` which is ultimately zero-initialized via > alloc_etherdev_mq(). > > 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. > --- > drivers/net/ethernet/amazon/ena/ena_netdev.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c > b/drivers/net/ethernet/amazon/ena/ena_netdev.c > index f955bde10cf9..3118a617c9b6 100644 > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c > @@ -3276,8 +3276,8 @@ static void ena_config_host_info(struct > ena_com_dev *ena_dev, struct pci_dev *pd > strscpy(host_info->kernel_ver_str, utsname()->version, > sizeof(host_info->kernel_ver_str) - 1); > host_info->os_dist = 0; > - strncpy(host_info->os_dist_str, utsname()->release, > - sizeof(host_info->os_dist_str) - 1); > + strscpy(host_info->os_dist_str, utsname()->release, > + sizeof(host_info->os_dist_str)); > host_info->driver_version = > (DRV_MODULE_GEN_MAJOR) | > (DRV_MODULE_GEN_MINOR << > ENA_ADMIN_HOST_INFO_MINOR_SHIFT) | > > --- > base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 > change-id: 20231005-strncpy-drivers-net-ethernet-amazon-ena-ena_netdev-c- > 6c4804466aa7 > > Best regards, > -- > Justin Stitt <justinst...@google.com> >
Thanks for submitting this change. The change looks good but the sentence "NUL-padding is not necessary as host_info is initialized to `ena_dev->host_attr.host_info` which is ultimately zero-initialized via alloc_etherdev_mq()." is inaccurate. host_info allocation is done in ena_com_allocate_host_info() via dma_alloc_coherent() and is not zero initialized by alloc_etherdev_mq(). I looked at both the documentation of dma_alloc_coherent() in https://www.kernel.org/doc/Documentation/DMA-API.txt as well as the code itself, and (maybe I'm wrong but) I didn't see 100% guarantees the that the memory is zero-initialized. However zero initialization of the destination doesn't matter in this case, because strscpy() guarantees a NULL termination. So please just remove this sentence from the commit message. Thanks, Arthur Kiyanovski
