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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id m7-20020aa78a07000000b0064fd4a6b306sm129832pfa.76.2023.10.05.16.22.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Oct 2023 16:22:12 -0700 (PDT) Date: Thu, 5 Oct 2023 16:22:10 -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] cavium/liquidio: replace deprecated strncpy with strscpy Message-ID: <202310051621.3893B1EA4@keescook> References: <20231005-strncpy-drivers-net-ethernet-cavium-liquidio-octeon_device-c-v1-1-9a207cef9438@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231005-strncpy-drivers-net-ethernet-cavium-liquidio-octeon_device-c-v1-1-9a207cef9438@google.com> X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Thu, Oct 05, 2023 at 10:52:34PM +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 expect `app_name` to be NUL-terminated: > dev_info(&oct->pci_dev->dev, > "Running %s (%llu Hz)\n", > app_name, CVM_CAST64(cs->corefreq)); > ... and it seems NUL-padding is not required, let's opt for strscpy(). > > For `oct->boardinfo.name/serial_number` let's opt for strscpy() as well > since it is expected to be NUL-terminated and does not require > NUL-padding as `oct` is zero-initialized in octeon_device.c +707: > | buf = vzalloc(size); > | if (!buf) > | return NULL; > | > | oct = (struct octeon_device *)buf; > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > 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/octeon_device.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.c b/drivers/net/ethernet/cavium/liquidio/octeon_device.c > index 364f4f912dc2..6b6cb73482d7 100644 > --- a/drivers/net/ethernet/cavium/liquidio/octeon_device.c > +++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.c > @@ -1217,10 +1217,10 @@ int octeon_core_drv_init(struct octeon_recv_info *recv_info, void *buf) > goto core_drv_init_err; > } > > - strncpy(app_name, > + strscpy(app_name, > get_oct_app_string( > (u32)recv_pkt->rh.r_core_drv_init.app_mode), > - sizeof(app_name) - 1); > + sizeof(app_name)); Direct replacement, good. > oct->app_mode = (u32)recv_pkt->rh.r_core_drv_init.app_mode; > if (recv_pkt->rh.r_core_drv_init.app_mode == CVM_DRV_NIC_APP) { > oct->fw_info.max_nic_ports = > @@ -1257,9 +1257,10 @@ int octeon_core_drv_init(struct octeon_recv_info *recv_info, void *buf) > memcpy(cs, get_rbd( > recv_pkt->buffer_ptr[0]) + OCT_DROQ_INFO_SIZE, sizeof(*cs)); > > - strncpy(oct->boardinfo.name, cs->boardname, OCT_BOARD_NAME); > - strncpy(oct->boardinfo.serial_number, cs->board_serial_number, > - OCT_SERIAL_LEN); > + strscpy(oct->boardinfo.name, cs->boardname, > + sizeof(oct->boardinfo.name)); > + strscpy(oct->boardinfo.serial_number, cs->board_serial_number, > + sizeof(oct->boardinfo.serial_number)); struct octeon_board_info { char name[OCT_BOARD_NAME]; char serial_number[OCT_SERIAL_LEN]; Good, sizeof()s match. Reviewed-by: Kees Cook -- Kees Cook