On Wed, Jun 01, 2016 at 04:34:28PM +0800, Xiubo Li wrote: > Since we cannot make sure the 'hook_mask' will always be none zero > here. If it equals to zero, the num_hooks will be zero too, and then > kmalloc() will return ZERO_SIZE_PTR, which is (void *)16. > > Then the following error check will fails: > ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); > if (ops == NULL) > return ERR_PTR(-ENOMEM); > > So this patch fix this with just doing the zero check before calling > kmalloc() is called. > > Maybe the case above will never happen here, but in theory. > > Signed-off-by: Xiubo Li <lixi...@cmss.chinamobile.com> > --- > net/netfilter/x_tables.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c > index c8a0b7d..4df8e38 100644 > --- a/net/netfilter/x_tables.c > +++ b/net/netfilter/x_tables.c > @@ -1185,6 +1185,9 @@ struct nf_hook_ops *xt_hook_link(const struct xt_table > *table, nf_hookfn *fn)
What kernel version are you using? I don't see xt_hook_link() in the development tree. > struct nf_hook_ops *ops; > int ret; > > + if (!num_hooks) > + return ERR_PTR(-EINVAL); > + > ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); > if (ops == NULL) > return ERR_PTR(-ENOMEM); > -- > 1.8.3.1 > > >
