From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B433570 for ; Fri, 23 Jul 2021 18:16:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1627064188; bh=ecvkC8x5/3D59+xc/e4I6ND0hbFLhwax+Ut44N6q2Jc=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:References:In-Reply-To; b=i4RmDwn9rfZkQpvnyD+5TqEw4w1R19km3lS4+dlPw1Ck2jZBPhkWuvL3HqM8Ti6P8 mR+cIAng+KP0SEDYcMc2RnkoxipetvMxSjx9+wQ0ca025ek1xpWRqtcEInLxVSdvOe oNlSY6IRcXs5ioSbFlWywTQNuUMNPlE9S7zTbFns= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from titan ([83.52.228.41]) by mail.gmx.net (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1N1wll-1l5AiT07BZ-012LD4; Fri, 23 Jul 2021 20:16:28 +0200 Date: Fri, 23 Jul 2021 20:16:25 +0200 From: Len Baker To: David Laight , Greg Kroah-Hartman Cc: Len Baker , Lee Jones , Romain Perier , Allen Pais , Dmitrii Wolf , Iain Craig , "linux-staging@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] staging/rtl8192u: Remove all strcpy() uses in favor of strscpy() Message-ID: <20210723165353.GD2612@titan> References: <20210718113207.10045-1-len.baker@gmx.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Provags-ID: V03:K1:84BVanMfKv1FcUJtwjIClWXu88suYQh0HtMUImvBEZxZyNqmKJC yKueTsz3rcnIMFGMaErRqwvo/Mtg+M1gD7sh+z4f3HRsNNwcKCs00+xqLk0ZnS+4eyO51Wz vmadz9x/OCw0yfcj76L/6Sm2KfcBbzKiaUyk/nAi93OuWQaxbSWBMhns4fhwZZ7MIJLy0oP uwFcimyKY4Aj9xz7UIi/g== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:9OIW+uX1jEQ=:nGU6ZSl+B1rlp/dVsaTXU3 FBmHK7/gff2E8TECaL7eFFBDeZ3tXScmZAzWcQ/hf3sgfznFQOmHDtduXfJg8BPR/KZJ9hSrZ EqjNaWirjJ4MArFxcWD6EZaUQfXWkiM9ulZeWzrvHy9sPzI2YFzROIS8VmvqBrkG4rUEwX+L3 04lsp0W81fowZ26MDsUTUDGJ1XgtiwJ086MU6sY+fAFYh2EuEph7Ptthkaoay3aBqzpOpp2S6 Y9cezSNSWua2M8mPn0rVoXpKZ/yFoDKnwh8cPu32/CneuVGAeYTT2Er1fJKXYS3CdRsDdMIis 9nyd39v1XlApgLtJVZ2QdFr+VmSjNF+h3ox4BMD1vx9yj11p33qgqTX6rbXe5gZMXm2VfLS9Q JHUakxzO8+F0rbBPgmgBXFrSgO7iWunURwnFNM8b84JcpZGmGcZ6IAlg7WHQy/GvE9rIME6E9 BzIN6TJXj21LgopfM2yKD/jvB1hoPd47WSIGfFr8NuwDS7K66Fv3jQc3sCfa2Q1vGivo7pKvR PTxtR9AkSdMe5ReF1dV4ew5TBy9lWZn6zDv6txHjkt2G26XYs6pKJkmfbln4MdZXyzyPsDJTU jxL/RapepB5wyEdUQZGP2yGdmzPiSNnxfjAz3TK7m2ClIyH1rP/5ANiFLwYfjkjna3q6EpG3X T33RHGvF//sUOBNsIIEziRMeh2S+3h/Rl6cM5zOkSOSaxf4FAJvKkhPEdWvdGg9rNwqP+xqZr VjGKB/KalMOrPindJhQWFoHZuxLwtRATbAY4BwiFlQvAmecWK7hDsm7mPz7dJpOPMpmspoOCS ccPDJUeCzAFC7/BQ5KAnh0+GRAvxNQQxqt5TzqiceRGmff+JSuw5pB4sOcWcT477cM88bf5RY PTWHU2nIrC+Tmt3VlfE+cglmXx0s02hYeQWqN1gXa6WeaMSOaRzEWKaLNRM1SUr48CEp7pJsG dYiJcIhA8i5QYPdU8/Sshcb43ucEywcaCif/pb26rbwqYZ9CAforKfkysGJz2hTivtufP7inH h26nEvYH0v27gVLmQZheZOKSuIXpGuB99rIxDQri0CGVc1vlrQyd62GW9koERG9YVR+EQdATF xTVrKciEIpH4b7jCLMFEJhBy0YOd3MZZHKG Content-Transfer-Encoding: quoted-printable Hi, On Mon, Jul 19, 2021 at 08:49:54AM +0000, David Laight wrote: > From: Len Baker > > Sent: 18 July 2021 12:32 > > > > strcpy() performs no bounds checking on the destination buffer. This > > could result in linear overflows beyond the end of the buffer, leading > > to all kinds of misbehaviors. The safe replacement is strscpy(). > > > > Signed-off-by: Len Baker > > --- > > drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > b/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > index ab885353f668..1a193f900779 100644 > > --- a/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > +++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c > > @@ -2226,7 +2226,8 @@ static void ieee80211_start_ibss_wq(struct work_= struct *work) > > mutex_lock(&ieee->wx_mutex); > > > > if (ieee->current_network.ssid_len =3D=3D 0) { > > - strcpy(ieee->current_network.ssid, IEEE80211_DEFAULT_TX_ESSID); > > + strscpy(ieee->current_network.ssid, IEEE80211_DEFAULT_TX_ESSID, > > + sizeof(ieee->current_network.ssid)); > > I'm pretty sure that recent compiler releases know enough > about strcpy() to error overflows for strcpy() from quoted > strings into char[]. > > If these checks are enabled for kernel builds then they are > actually safer than the run-time check above > (which can be mistyped). > > The compiler can (it may not) convert the strcpy() into a memcpy() > using the compile-time length of the quoted string. I agree, but if we want to remove this function entirely from the kernel [= 1] we need to replace all the strcpy() uses as a previous step. And the safe replacement is strscpy() [2]. [1] https://github.com/KSPP/linux/issues/88 [2] https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK= 1 1PT, UK > Registration No: 1397386 (Wales) > Thanks for the feedback, Len