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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id p18-20020aa78612000000b00689f5940061sm6902037pfn.17.2023.10.09.11.57.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Oct 2023 11:57:21 -0700 (PDT) Date: Mon, 9 Oct 2023 11:57:19 -0700 From: Kees Cook To: Justin Stitt Cc: Hauke Mehrtens , Andrew Lunn , Florian Fainelli , Vladimir Oltean , "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] net: dsa: lantiq_gswip: replace deprecated strncpy with ethtool_sprintf Message-ID: <202310091156.978D4E1@keescook> References: <20231009-strncpy-drivers-net-dsa-lantiq_gswip-c-v1-1-d55a986a14cc@google.com> <202310091134.67A4236E@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202310091134.67A4236E@keescook> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 09, 2023 at 11:34:27AM -0700, Kees Cook wrote: > On Mon, Oct 09, 2023 at 06:24:20PM +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. > > > > ethtool_sprintf() is designed specifically for get_strings() usage. > > Let's replace strncpy in favor of this more robust and easier to > > understand interface. > > > > 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/dsa/lantiq_gswip.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c > > index 3c76a1a14aee..d60bc2e37701 100644 > > --- a/drivers/net/dsa/lantiq_gswip.c > > +++ b/drivers/net/dsa/lantiq_gswip.c > > @@ -1759,8 +1759,7 @@ static void gswip_get_strings(struct dsa_switch *ds, int port, u32 stringset, > > return; > > > > for (i = 0; i < ARRAY_SIZE(gswip_rmon_cnt); i++) > > - strncpy(data + i * ETH_GSTRING_LEN, gswip_rmon_cnt[i].name, > > - ETH_GSTRING_LEN); > > + ethtool_sprintf(&data, "%s", gswip_rmon_cnt[i].name); > > Sorry, I read too fast: this should be "data", not "&data", yeah? As I said in the other email, please ignore me. &data is correct. I'm not used to ethtool_sprintf(), clearly. :) My original Reviewed-by stands. Sorry for the noise! -Kees -- Kees Cook