Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> On Sun, 2018-01-28 at 07:41 -0800, Eric Dumazet wrote:
> > From: Eric Dumazet <edumazet@xxxxxxxxxx>
> >
> > Syzbot reported a WARN() in proc_create_data() [1]
> >
> > Issue here is that xt_hashlimit does not check that user space provided
> > an empty table name.
>
> > Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> > Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
> > ---
> > net/netfilter/xt_hashlimit.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
> > index 5da8746f7b88ff4c9446f256e542e823a6a561b0..eae732e013df92a364b500645360d4606c283a75 100644
> > --- a/net/netfilter/xt_hashlimit.c
> > +++ b/net/netfilter/xt_hashlimit.c
> > @@ -894,6 +894,8 @@ static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
> > return -ERANGE;
> > }
> >
> > + if (!name[0])
> > + return -EINVAL;
> > mutex_lock(&hashlimit_mutex);
> > *hinfo = htable_find_get(net, name, par->family);
> > if (*hinfo == NULL) {
>
> I wonder if we should also check if name includes a '/' ?
>
> if (!name[0] || strchr(name, '/'))
> return -EINVAL;
I think there should be a helper for this to reject
- 0 length
- /
- .
- ..
in hashlimit case name is IFNMASIZ so we could even use
dev_valid_name() here.
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