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[34.86.5.128]) by smtp.gmail.com with UTF8SMTPSA id d75a77b69052e-4af0e32d04asm123174241cf.0.2025.08.11.07.27.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Aug 2025 07:27:48 -0700 (PDT) Date: Mon, 11 Aug 2025 10:27:47 -0400 From: Willem de Bruijn To: =?UTF-8?B?TWlndWVsIEdhcmPDrWE=?= , netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, willemdebruijn.kernel@gmail.com, jasowang@redhat.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, skhan@linuxfoundation.org, =?UTF-8?B?TWlndWVsIEdhcmPDrWE=?= Message-ID: <6899fde3dbfd6_532b129461@willemb.c.googlers.com.notmuch> In-Reply-To: <20250811112207.97371-1-miguelgarciaroman8@gmail.com> References: <20250811112207.97371-1-miguelgarciaroman8@gmail.com> Subject: Re: [PATCH] net: tun: replace strcpy with strscpy for ifr_name Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable [PATCH net-next] Miguel Garc=C3=ADa wrote: > Replace the strcpy() calls that copy the device name into ifr->ifr_name= > with strscpy() to avoid potential overflows and guarantee NUL terminati= on. NULL > Destination is ifr->ifr_name (size IFNAMSIZ). > = > Tested in QEMU (BusyBox rootfs): > - Created TUN devices via TUNSETIFF helper > - Set addresses and brought links up > - Verified long interface names are safely truncated (IFNAMSIZ-1) > = > Signed-off-by: Miguel Garc=C3=ADa > --- > drivers/net/tun.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > = > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index f8c5e2fd04df..e4c6c1118acb 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -2800,13 +2800,13 @@ static int tun_set_iff(struct net *net, struct = file *file, struct ifreq *ifr) > if (netif_running(tun->dev)) > netif_tx_wake_all_queues(tun->dev); > = > - strcpy(ifr->ifr_name, tun->dev->name); > + strscpy(ifr->ifr_name, tun->dev->name, IFNAMSIZ); Since both dst and src are arrays of IFNAMSIZ, can drop the third argument. Then it is inferred from the field sizes, which is more robust. > return 0; > } > = > static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr) > { > - strcpy(ifr->ifr_name, tun->dev->name); > + strscpy(ifr->ifr_name, tun->dev->name, IFNAMSIZ); > = > ifr->ifr_flags =3D tun_flags(tun); > = > -- = > 2.34.1 > =