From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Date: Tue, 05 Oct 2010 16:43:06 +0000 Subject: Re: [patch] isdn: strcpy() => strlcpy() Message-Id: <20101005164306.GP19804@ZenIV.linux.org.uk> List-Id: References: <20101005163448.GH5692@bicker> In-Reply-To: <20101005163448.GH5692@bicker> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dan Carpenter Cc: Karsten Keil , netdev@vger.kernel.org, kernel-janitors@vger.kernel.org On Tue, Oct 05, 2010 at 06:34:48PM +0200, Dan Carpenter wrote: > setup.phone and setup.eazmsn are 32 character buffers. > rcvmsg.msg_data.byte_array is a 48 character buffer. > sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn is 50 chars. > > I changed the strcpy() so strlcpy() because that's safest. ITYM "I papered it over, so potentially broken behaviour is harder to find now"... > - strcpy(setup.phone,&(rcvmsg.msg_data.byte_array[4])); > - strcpy(setup.eazmsn, > - sc_adapter[card]->channel[rcvmsg.phy_link_no-1].dn); > + strlcpy(setup.phone, &(rcvmsg.msg_data.byte_array[4]), > + sizeof(setup.phone)); OK, so what should be done if the damn array contents _is_ longer than that? > + strlcpy(setup.eazmsn, > + sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn, > + sizeof(setup.eazmsn)); Ditto. > - strcpy(sc_adapter[card]->channel[rcvmsg.phy_link_no-1].dn,rcvmsg.msg_data.byte_array); > + strlcpy(sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn, > + rcvmsg.msg_data.byte_array, > + sizeof(rcvmsg.msg_data.byte_array)); Huh? Is it or is it not NUL-terminated? If it is, then change is pure cargo-culting; if it is not, you are asking for nasal daemons to fly.