From: Jakub Kicinski <kuba@kernel.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Peter Collingbourne <pcc@google.com>,
"David S. Miller" <davem@davemloft.net>,
Colin Ian King <colin.king@canonical.com>,
Cong Wang <cong.wang@bytedance.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Greg KH <gregkh@linuxfoundation.org>,
"Arnd Bergmann" <arnd@kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v2] net: don't unconditionally copy_from_user a struct ifreq for socket ioctls
Date: Wed, 1 Sep 2021 07:03:56 -0700 [thread overview]
Message-ID: <20210901070356.750ea996@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <bf0f47974d7141358d810d512d4b9a00@AcuMS.aculab.com>
On Wed, 1 Sep 2021 08:22:42 +0000 David Laight wrote:
> From: Jakub Kicinski
> > Sent: 31 August 2021 17:30
> >
> > On Thu, 26 Aug 2021 12:46:01 -0700 Peter Collingbourne wrote:
> > > @@ -3306,6 +3308,8 @@ static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd,
> > > struct ifreq ifreq;
> > > u32 data32;
> > >
> > > + if (!is_socket_ioctl_cmd(cmd))
> > > + return -ENOTTY;
> > > if (copy_from_user(ifreq.ifr_name, u_ifreq32->ifr_name, IFNAMSIZ))
> > > return -EFAULT;
> > > if (get_user(data32, &u_ifreq32->ifr_data))
> >
> > Hi Peter, when resolving the net -> net-next merge conflict I couldn't
> > figure out why this chunk is needed. It seems all callers of
> > compat_ifr_data_ioctl() already made sure it's a socket IOCTL.
> > Please double check my resolution (tip of net-next) and if this is
> > indeed unnecessary perhaps send a cleanup? Thanks!
>
> To stop the copy_from_user() faulting when the user buffer
> isn't long enough.
> In particular for iasatty() on arm with tagged pointers.
Let me rephrase. is_socket_ioctl_cmd() is always true here. There were
only two callers, both check cmd is of specific, "sockety" type.
next prev parent reply other threads:[~2021-09-01 14:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-26 19:46 [PATCH v2] net: don't unconditionally copy_from_user a struct ifreq for socket ioctls Peter Collingbourne
2021-08-27 8:50 ` patchwork-bot+netdevbpf
2021-08-31 16:30 ` Jakub Kicinski
2021-09-01 8:22 ` David Laight
2021-09-01 14:03 ` Jakub Kicinski [this message]
2021-09-01 18:01 ` Peter Collingbourne
2021-09-01 23:20 ` Jakub Kicinski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210901070356.750ea996@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com \
--to=kuba@kernel.org \
--cc=David.Laight@ACULAB.COM \
--cc=arnd@kernel.org \
--cc=colin.king@canonical.com \
--cc=cong.wang@bytedance.com \
--cc=davem@davemloft.net \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pcc@google.com \
--cc=stable@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).