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[95.237.55.30]) by smtp.gmail.com with ESMTPSA id y21sm9195860edv.31.2021.04.13.06.24.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Apr 2021 06:24:32 -0700 (PDT) From: "Fabio M. De Francesco" To: Greg Kroah-Hartman Cc: outreachy-kernel@googlegroups.com, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [Outreachy kernel] [PATCH] staging: rtl8192u: ieee80211: Replaced strncpy() with strscpy() Date: Tue, 13 Apr 2021 15:24:31 +0200 Message-ID: <5414987.Cp2PYjnBm2@linux.local> In-Reply-To: References: <20210413123041.24260-1-fmdefrancesco@gmail.com> <4666289.4L6Ep8XSK1@linux.local> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, April 13, 2021 3:16:17 PM CEST Greg Kroah-Hartman wrote: > On Tue, Apr 13, 2021 at 03:12:02PM +0200, Fabio M. De Francesco wrote: > > On Tuesday, April 13, 2021 2:59:29 PM CEST Greg Kroah-Hartman wrote: > > > On Tue, Apr 13, 2021 at 02:30:41PM +0200, Fabio M. De Francesco=20 wrote: > > > > Replaced strncpy() with strscpy() because of compilation time > > > > warnings > > > > about possible truncation of output [-Wstringop-truncation]. > > >=20 > > > build warnings? What build warnings? > >=20 > > drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c:1388:5: warning: > > =E2=80=98strncpy=E2=80=99 output may be truncated copying 32 bytes from= a string of > > length 32 [-Wstringop-truncation] > >=20 > > 1388 | strncpy(tmp_ssid, ieee->current_network.ssid, > >=20 > > IW_ESSID_MAX_SIZE); >=20 > That's implying that there is a real bug here, not that just replacing > it with a different call is going to solve this, right? >=20 > And how do you see that, I can't see that in my builds. > I see that with flag W=3D1 like in=20 make -j8 drivers/staging/rtl8192u/ W=3D1 However I also think it's not a real issue in this context. Just that strscpy() is preferred and get rid of warnings. You only can judge if a patch is worth. I just thought that gcc is (mostly) right in pointing out warnings like=20 that. Thanks, =46abio >=20 > > > > Furthermore, according to the Linux official documentation, > > > > strscpy() > > > > is > > > > preferred to strncpy. > > > >=20 > > > > Signed-off-by: Fabio M. De Francesco > > > > --- > > > >=20 > > > > drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c | 4 ++-- > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > >=20 > > > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > > > b/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c index > > > > 25ea8e1b6b65..aa58eedf5e86 100644 > > > > --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > > > +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > > > @@ -1385,12 +1385,12 @@ inline void > > > > ieee80211_softmac_new_net(struct > > > > ieee80211_device *ieee, struct ieee> > > > >=20 > > > > * essid provided by the user. > > > > */ > > > > =09 > > > > if (!ssidbroad) { > > > >=20 > > > > - strncpy(tmp_ssid, ieee- > > > > > >current_network.ssid, IW_ESSID_MAX_SIZE); > > > > > > > + strscpy(tmp_ssid, ieee- > > > > > >current_network.ssid, IW_ESSID_MAX_SIZE); > > > > > > Are you sure you can just replace this like this? > >=20 > > I surely was... but now I'm not anymore, since your review :) > >=20 > > Maybe you mean I have to check possible return of -E2BIG? > > Did you mean something else? > > May you please elaborate further? >=20 > If it was as simple as search/replace, we would have already done that > on the whole codebase at once. It's not that simple :) >=20 > thanks, >=20 > greg k-h