netdev - Re: [PATCH 1/2] samples: bpf: ensure that we don't load over MAX

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Message-ID: <20180713151541.m6ksulnjb6qsh24w@mwanda>
Date:   Fri, 13 Jul 2018 18:15:41 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Colin Ian King <colin.king@...onical.com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>, netdev@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 1/2] samples: bpf: ensure that we don't load over
 MAX_PROGS programs

On Fri, Jul 13, 2018 at 04:13:30PM +0100, Colin Ian King wrote:
> On 13/07/18 16:11, Dan Carpenter wrote:
> > I can't see that we check prog_cnt to ensure it doesn't go over
> > MAX_PROGS.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> > 
> > diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
> > index 89161c9ed466..904e775d1a44 100644
> > --- a/samples/bpf/bpf_load.c
> > +++ b/samples/bpf/bpf_load.c
> > @@ -107,6 +107,9 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
> >  		return -1;
> >  	}
> >  
> > +	if (prog_cnt == MAX_PROGS)
> > +		return -1;
> > +
> 
> Should that be "if (prog_cnt >= MAX_PROGS)" ?

It's incremented one at a time so it can't go over.

regards,
dan carpenter