On Sun, Jan 28, 2018 at 09:54:05AM -0800, Eric Dumazet 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;
We can probably add our own variant of dev_valid_name?
bool nf_valid_name(const char *name, size_t len)
{
if (*name == '\0')
return false;
if (strlen(name) >= len)
return false;
if (!strcmp(name, ".") || !strcmp(name, ".."))
return false;
while (*name) {
if (*name == '/' || *name == ':' || isspace(*name))
return false;
name++;
}
return true;
}
Or place this in the core, something like:
bool net_valid_name(const char *name, size_t len)
{
...
}
then use it from dev_valid_name()
bool dev_valid_name(const char *name)
{
return net_valid_name(name, IFNAMSIZ);
}
@Eric, I can give it a shot here to this, just let me know. Thanks!
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