On Fri, Jan 29, 2016 at 11:25:35AM +0800, Zhouyi Zhou wrote: > I think hackers chould build a malicious h323 packet to overflow > the pointer p which will panic during the memcpy(addr, p, len) > For example, he may fabricate a very large taddr->ipAddress.ip; > As suggested by Eric, this module is protected by a lock (nf_h323_lock) > so adding a variable h323_buffer_valid_bytes that would contain > the number of valid bytes would not require to change prototypes of > get_h2x5_addr. > > Signed-off-by: Zhouyi Zhou <yizhouzhou@xxxxxxxxx> > Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx> > Reviewed-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> > > --- > net/netfilter/nf_conntrack_h323_main.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c > index 9511af0..65d84bc 100644 > --- a/net/netfilter/nf_conntrack_h323_main.c > +++ b/net/netfilter/nf_conntrack_h323_main.c > @@ -110,6 +110,11 @@ int (*nat_q931_hook) (struct sk_buff *skb, > > static DEFINE_SPINLOCK(nf_h323_lock); > static char *h323_buffer; > +static unsigned int h323_buffer_valid_bytes; > +/* check offset overflow and out of range data reference */ > +#define CHECK_BOUND(p, n) ((n) > h323_buffer_valid_bytes || \ > + ((void *)(p) + (n) - (void *)h323_buffer \ > + > h323_buffer_valid_bytes)) We don't want obscure macros. You add a function for this, the compiler will likely inline it. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
