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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id x5-20020a17090abc8500b0026f4bb8b2casm4138869pjr.6.2023.10.05.16.14.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Oct 2023 16:14:36 -0700 (PDT) Date: Thu, 5 Oct 2023 16:14:31 -0700 From: Kees Cook To: Justin Stitt Cc: Derek Chickles , Satanand Burla , Felix Manlunas , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH] liquidio: replace deprecated strncpy/strcpy with strscpy Message-ID: <202310051610.01453F60F@keescook> References: <20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_ethtool-c-v1-1-ab565ab4d197@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_ethtool-c-v1-1-ab565ab4d197@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 05, 2023 at 09:33:19PM +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. > > NUL-padding is not required as drvinfo is memset to 0: > | memset(drvinfo, 0, sizeof(struct ethtool_drvinfo)); > > 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 > --- > Note: build-tested only. > --- > drivers/net/ethernet/cavium/liquidio/lio_ethtool.c | 18 ++++++++++-------- > 1 file changed, 10 insertions(+), 8 deletions(-) > > diff --git a/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c b/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c > index 9d56181a301f..d3e07b6ed5e1 100644 > --- a/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c > +++ b/drivers/net/ethernet/cavium/liquidio/lio_ethtool.c > @@ -442,10 +442,11 @@ lio_get_drvinfo(struct net_device *netdev, struct ethtool_drvinfo *drvinfo) > oct = lio->oct_dev; > > memset(drvinfo, 0, sizeof(struct ethtool_drvinfo)); struct ethtool_drvinfo { char driver[32]; ... char fw_version[ETHTOOL_FWVERS_LEN]; char bus_info[ETHTOOL_BUSINFO_LEN]; > - strcpy(drvinfo->driver, "liquidio"); > + strscpy(drvinfo->driver, "liquidio", sizeof(drvinfo->driver)); Yup, this is basically what FORTIFY_SOURCE will do automatically to strcpy(). > - strncpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version, > - ETHTOOL_FWVERS_LEN); > + strscpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version, > + sizeof(drvinfo->fw_version)); Yup, ETHTOOL_FWVERS_LEN == sizeof(drvinfo->fw_version) > - strncpy(drvinfo->bus_info, pci_name(oct->pci_dev), 32); > + strscpy(drvinfo->bus_info, pci_name(oct->pci_dev), > + sizeof(drvinfo->bus_info)); Yup, ETHTOOL_BUSINFO_LEN == sizeof(drvinfo->bus_info) > } > > static void > @@ -458,10 +459,11 @@ lio_get_vf_drvinfo(struct net_device *netdev, struct ethtool_drvinfo *drvinfo) > oct = lio->oct_dev; > > memset(drvinfo, 0, sizeof(struct ethtool_drvinfo)); > - strcpy(drvinfo->driver, "liquidio_vf"); > - strncpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version, > - ETHTOOL_FWVERS_LEN); > - strncpy(drvinfo->bus_info, pci_name(oct->pci_dev), 32); > + strscpy(drvinfo->driver, "liquidio_vf", sizeof(drvinfo->driver)); > + strscpy(drvinfo->fw_version, oct->fw_info.liquidio_firmware_version, > + sizeof(drvinfo->fw_version)); > + strscpy(drvinfo->bus_info, pci_name(oct->pci_dev), > + sizeof(drvinfo->bus_info)); > } Yup, looks good. Reviewed-by: Kees Cook > > static int > > --- > base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 > change-id: 20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_ethtool-c-b6932c0f80f1 > > Best regards, > -- > Justin Stitt > > -- Kees Cook