netdev - Re: [PATCH] dns_resolver: assure that dns_query() result is null-terminated

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Message-ID: <1402167452.4806.0.camel@schoellingm.dzne.de>
Date:	Sat, 07 Jun 2014 20:57:32 +0200
From:	Manuel Schoelling <manuel.schoelling@....de>
To:	Trond Myklebust <trond.myklebust@...marydata.com>
Cc:	"Miller David S." <davem@...emloft.net>,
	jeffrey.t.kirsher@...el.com,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Linux Kernel mailing list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dns_resolver: assure that dns_query() result is
 null-terminated

LOL, that was stupid!
Sorry, I'll send a corrected version in a second...

On Sa, 2014-06-07 at 14:54 -0400, Trond Myklebust wrote:
> On Sat, Jun 7, 2014 at 1:56 PM, Manuel Schölling
> <manuel.schoelling@....de> wrote:
> > dns_query() credulously assumes that keys are null-terminated and
> > returns a copy of a memory block that is off by one.
> > ---
> >  net/dns_resolver/dns_query.c |    4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c
> > index e7b6d53..53be635 100644
> > --- a/net/dns_resolver/dns_query.c
> > +++ b/net/dns_resolver/dns_query.c
> > @@ -149,7 +149,9 @@ int dns_query(const char *type, const char *name, size_t namelen,
> >         if (!*_result)
> >                 goto put;
> >
> > -       memcpy(*_result, upayload->data, len + 1);
> > +       memcpy(*_result, upayload->data, len);
> > +       *_result[len+1] = '\0';
> 
> Off by one...
> 
> > +
> >         if (_expiry)
> >                 *_expiry = rkey->expiry;
> >
> > --
> > 1.7.10.4
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> 
> 
> 


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