| Message ID | 1467815048-2240-4-git-send-email-pablo@netfilter.org |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Hello. On 07/06/2016 05:23 PM, Pablo Neira Ayuso wrote: > From: Xiubo Li <lixiubo@cmss.chinamobile.com> > > Since we cannot make sure that the 'hook_mask' will always be none > zero here. Non-zero, you mean? > 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 will fix this with just doing the zero check before > kmalloc() is called. > > Maybe the case above will never happen here, but in theory. > > Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> > Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> > --- > 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 c69c892..8aff34e 100644 > --- a/net/netfilter/x_tables.c > +++ b/net/netfilter/x_tables.c > @@ -1460,6 +1460,9 @@ xt_hook_ops_alloc(const struct xt_table *table, nf_hookfn *fn) > uint8_t hooknum; > struct nf_hook_ops *ops; > > + if (!num_hooks) > + return ERR_PTR(-EINVAL); > + > ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); BTW, asking to be kcalloc() instead? [...] MBR, Sergei
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index c69c892..8aff34e 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1460,6 +1460,9 @@ xt_hook_ops_alloc(const struct xt_table *table, nf_hookfn *fn) uint8_t hooknum; struct nf_hook_ops *ops; + if (!num_hooks) + return ERR_PTR(-EINVAL); + ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); if (ops == NULL) return ERR_PTR(-ENOMEM);