From: Pablo Neira Ayuso <pablo@netfilter.org>
To: santosh prasad nayak <santoshprasadnayak@gmail.com>
Cc: bart.de.schuymer@pandora.be, kaber@trash.net,
shemminger@vyatta.com, davem@davemloft.net,
netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org,
coreteam@netfilter.org, bridge@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-janitors@vger.kernel.org,
Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH 1/3] netfilter: Fix copy_to_user too small size parametre.
Date: Thu, 1 Mar 2012 14:03:11 +0100 [thread overview]
Message-ID: <20120301130311.GA7429@1984> (raw)
In-Reply-To: <CAOD=uF6yqCETUG8jMCmjYDM+L1DsM91OiRveONJkNxMf=skTSg@mail.gmail.com>
On Thu, Mar 01, 2012 at 04:15:05PM +0530, santosh prasad nayak wrote:
> Hi Pablo.
>
> copy_to_user( dest, source, length)
>
> Normally, 'length' is equal to 'sizeof (source) '.
>
> In this case "length" = 32
> "sizeof(source)" = 29.
>
> Is it intentional ?
ebtables expects 32 bytes names.
> Won't it copy extra 3 bytes of kernel data to userspace ?
You're right. We have to copy 29 bytes but we have to fill the
remaining bytes with zeroes. I think something like:
char name[EBT_FUNCTION_MAXNAMELEN] = {};
/* user-space ebtables expects 32 bytes-long names, but xt_match uses
* 29 bytes for that. */
sprintf(name, "%s", m->u.match->name);
if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
...
will resolve this issue.
Would you resend a new patch?
next prev parent reply other threads:[~2012-03-01 13:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-01 9:16 [PATCH 1/3] netfilter: Fix copy_to_user too small size parametre santosh nayak
2012-03-01 10:18 ` Pablo Neira Ayuso
2012-03-01 10:45 ` santosh prasad nayak
2012-03-01 13:03 ` Pablo Neira Ayuso [this message]
2012-03-01 13:51 ` santosh prasad nayak
2012-03-01 11:37 ` Dan Carpenter
2012-03-01 13:06 ` Pablo Neira Ayuso
2012-03-01 13:13 ` Dan Carpenter
2012-03-01 11:31 ` Dan Carpenter
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=20120301130311.GA7429@1984 \
--to=pablo@netfilter.org \
--cc=bart.de.schuymer@pandora.be \
--cc=bridge@lists.linux-foundation.org \
--cc=coreteam@netfilter.org \
--cc=dan.carpenter@oracle.com \
--cc=davem@davemloft.net \
--cc=kaber@trash.net \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=netfilter@vger.kernel.org \
--cc=santoshprasadnayak@gmail.com \
--cc=shemminger@vyatta.com \
/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).