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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id 14-20020a17090a19ce00b00277371fd346sm4462196pjj.30.2023.10.05.16.18.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Oct 2023 16:18:26 -0700 (PDT) Date: Thu, 5 Oct 2023 16:18:26 -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 with strscpy Message-ID: <202310051617.3C4A40C5@keescook> References: <20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_vf_rep-c-v1-1-92123a747780@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_vf_rep-c-v1-1-92123a747780@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 05, 2023 at 09:55:06PM +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 rep_cfg is memset to 0: > | memset(&rep_cfg, 0, sizeof(rep_cfg)); > > 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_vf_rep.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c > index 600de587d7a9..aa6c0dfb6f1c 100644 > --- a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c > +++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c > @@ -638,7 +638,8 @@ lio_vf_rep_netdev_event(struct notifier_block *nb, > memset(&rep_cfg, 0, sizeof(rep_cfg)); > rep_cfg.req_type = LIO_VF_REP_REQ_DEVNAME; > rep_cfg.ifidx = vf_rep->ifidx; > - strncpy(rep_cfg.rep_name.name, ndev->name, LIO_IF_NAME_SIZE); > + strscpy(rep_cfg.rep_name.name, ndev->name, > + sizeof(rep_cfg.rep_name.name)); struct lio_vf_rep_req { ... union { struct lio_vf_rep_name { char name[LIO_IF_NAME_SIZE]; } rep_name; Yup, sizeof(rep_cfg.rep_name.name) == LIO_IF_NAME_SIZE. Reviewed-by: Kees Cook -- Kees Cook