Hello.
On 2/2/2016 8:37 AM, 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.
In order to avoid this, I add a valid memory reference check in
get_h2x5_addr functions.
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>
---
net/netfilter/nf_conntrack_h323_main.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
index 9511af0..21665ec 100644
--- a/net/netfilter/nf_conntrack_h323_main.c
+++ b/net/netfilter/nf_conntrack_h323_main.c
@@ -110,6 +110,25 @@ int (*nat_q931_hook) (struct sk_buff *skb,
static DEFINE_SPINLOCK(nf_h323_lock);
static char *h323_buffer;
+static int h323_buffer_valid_bytes;
+
+static bool h323_buffer_ref_valid(void *p, int len)
+{
+
+ if ((unsigned long)len > h323_buffer_valid_bytes) {
+ return false;
+ }
{} not needed.
+
+ if (p + len > (void *)h323_buffer + h323_buffer_valid_bytes) {
+ return false;
+ }
Likewise.
+
+ if (p < (void *)h323_buffer) {
+ return false;
+ }
Likewise.
[...]
MBR, Sergei
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