On Mon, 2016-02-01 at 18:58 +0100, Pablo Neira Ayuso wrote: > 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 <yizhouz...@ict.ac.cn> > > Signed-off-by: Eric Dumazet <eric.duma...@gmail.com> > > Reviewed-by: Sergei Shtylyov <sergei.shtyl...@cogentembedded.com> > > > > --- > > 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.
BTW, I did not signed-off this patch. Zhouyi Zho, just add your own signature, let people add their own. Thanks.
