From: Kees Cook <keescook@chromium.org>
To: Rao Shoaib <rao.shoaib@oracle.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>,
kernel test robot <lkp@intel.com>,
Veaceslav Falico <vfalico@gmail.com>,
Andy Gospodarek <andy@greyhouse.net>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] net: bonding: Use strscpy() instead of manually-truncated strncpy()
Date: Wed, 2 Jun 2021 13:02:02 -0700 [thread overview]
Message-ID: <202106021257.F0DFED3@keescook> (raw)
In-Reply-To: <b53fc81b-2348-54f1-72ca-d143d34bf780@oracle.com>
On Wed, Jun 02, 2021 at 12:46:46PM -0700, Rao Shoaib wrote:
> Would it make sense to also replace the other strncpy in the same file.
strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
I couldn't tell if this was a non-string, if it needed padding, etc. The
one I fixed below appears to be null-terminated? (Though now that I look
at it, perhaps it should be using strscpy_pad().)
And there are a bunch of other manual truncations in the kernel on
ifr_name:
$ git grep ifr_name | grep 'IFNAMSIZ.*=.*0'
drivers/net/tun.c: ifr.ifr_name[IFNAMSIZ-1] = '\0';
net/core/dev_ioctl.c: ifr->ifr_name[IFNAMSIZ-1] = 0;
net/core/dev_ioctl.c: ifr->ifr_name[IFNAMSIZ-1] = 0;
net/decnet/dn_dev.c: ifr->ifr_name[IFNAMSIZ-1] = 0;
net/ieee802154/socket.c: ifr.ifr_name[IFNAMSIZ-1] = 0;
net/ipv4/devinet.c: ifr->ifr_name[IFNAMSIZ - 1] = 0;
net/wireless/wext-core.c: iwr.ifr_name[IFNAMSIZ-1] = 0;
tools/lib/bpf/xsk.c: ifr.ifr_name[IFNAMSIZ - 1] = '\0';
And given the copy_to_user() that might happen, I think this should
absolutely be strscpy_pad(). I will send a v2...
-Kees
>
> Shoaib
>
> On 6/2/21 11:11 AM, Kees Cook wrote:
> > Silence this warning by just using strscpy() directly:
> >
> > drivers/net/bonding/bond_main.c:4877:3: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
> > 4877 | strncpy(params->primary, primary, IFNAMSIZ);
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > Reported-by: kernel test robot <lkp@intel.com>
> > Link: https://lore.kernel.org/lkml/202102150705.fdR6obB0-lkp@intel.com
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > drivers/net/bonding/bond_main.c | 6 ++----
> > 1 file changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> > index c5a646d06102..ecfc48f2d0d0 100644
> > --- a/drivers/net/bonding/bond_main.c
> > +++ b/drivers/net/bonding/bond_main.c
> > @@ -5329,10 +5329,8 @@ static int bond_check_params(struct bond_params *params)
> > (struct reciprocal_value) { 0 };
> > }
> > - if (primary) {
> > - strncpy(params->primary, primary, IFNAMSIZ);
> > - params->primary[IFNAMSIZ - 1] = 0;
> > - }
> > + if (primary)
> > + strscpy(params->primary, primary, sizeof(params->primary));
> > memcpy(params->arp_targets, arp_target, sizeof(arp_target));
--
Kees Cook
prev parent reply other threads:[~2021-06-02 20:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-02 18:11 [PATCH] net: bonding: Use strscpy() instead of manually-truncated strncpy() Kees Cook
2021-06-02 19:46 ` Rao Shoaib
2021-06-02 20:02 ` Kees Cook [this message]
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