Thanks Eric for your review and advice.
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;
Signed-off-by: Zhouyi Zhou <yizhouz...@ict.ac.cn>
---
net/netfilter/nf_conntrack_h323_main.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/net/netfilter/nf_conntrack_h323_main.c
b/net/netfilter/nf_conntrack_h323_main.c
index 9511af0..ccd08c5 100644
--- a/net/netfilter/nf_conntrack_h323_main.c
+++ b/net/netfilter/nf_conntrack_h323_main.c
@@ -110,6 +110,7 @@ int (*nat_q931_hook) (struct sk_buff *skb,
static DEFINE_SPINLOCK(nf_h323_lock);
static char *h323_buffer;
+#define CHECK_BOUND(p, n) ((void *)p + n - (void *)h323_buffer > 65536)
static struct nf_conntrack_helper nf_conntrack_helper_h245;
static struct nf_conntrack_helper nf_conntrack_helper_q931[];
@@ -247,6 +248,9 @@ static int get_h245_addr(struct nf_conn *ct, const unsigned
char *data,
return 0;
}
+ if (CHECK_BOUND(p, len + sizeof(__be16)))
+ return 0;
+
memcpy(addr, p, len);
memset((void *)addr + len, 0, sizeof(*addr) - len);
memcpy(port, p + len, sizeof(__be16));
@@ -669,6 +673,9 @@ int get_h225_addr(struct nf_conn *ct, unsigned char *data,
return 0;
}
+ if (CHECK_BOUND(p, len + sizeof(__be16)))
+ return 0;
+
memcpy(addr, p, len);
memset((void *)addr + len, 0, sizeof(*addr) - len);
memcpy(port, p + len, sizeof(__be16));
--
1.7.10.4
