From: Phil Sutter <phil@nwl.cc>
To: dyslexicatheist <dyslexicatheist@protonmail.com>
Cc: "netfilter-devel@vger.kernel.org" <netfilter-devel@vger.kernel.org>
Subject: Re: invalid read in
Date: Mon, 3 Feb 2020 18:30:03 +0100 [thread overview]
Message-ID: <20200203173003.GF20229@orbyte.nwl.cc> (raw)
In-Reply-To: <7BnNOPQw33ulxkwoWPovsrpwB_JPbS5nJhaTevbPCUkPRxObOpyrmqo3pFe_h82tov85DMfE1cYdX1xX3xhHNLbTef3XXmkqU26_ulUKpfY=@protonmail.com>
Hi,
On Mon, Feb 03, 2020 at 05:14:45PM +0000, dyslexicatheist wrote:
> On Monday, February 3, 2020 4:31 PM, Phil Sutter <phil@nwl.cc> wrote:
> > On Mon, Feb 03, 2020 at 01:54:31PM +0000, dyslexicatheist wrote:
> >
> > I guess this is the typical "problem" situation in which userspace uses
> > a non-zeroed buffer to feed into sendto() and due to padding not
> > every byte was written to. So basically userspace "leaks" garbage to
> > kernel, which is something I'd consider harmless and merely a minor
> > inconvenience when analyzing with valgrind. I usually suffer from this
> > as well since libmnl()'s allocation routines don't zero the buffer
> > either.
> >
> > In your case, I'd say the error message disappears if you add
> > 'memset(&u, 0, sizeof(u))' to the beginning of nfq_set_mode().
>
> thanks for your help Phil. I have just tried this but unfortunately it didn't change the outcome. Also tried other variations such as memset'ing both &u and the ¶ms struct, but nada.
Maybe you need to apply the same to __build_send_cfg_msg() as well?
Cheers, Phil
next prev parent reply other threads:[~2020-02-03 17:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 13:54 invalid read in dyslexicatheist
2020-02-03 16:31 ` Phil Sutter
2020-02-03 17:14 ` dyslexicatheist
2020-02-03 17:30 ` Phil Sutter [this message]
2020-02-03 17:49 ` dyslexicatheist
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