From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhouyi Zhou Subject: [PATCH 1/1] netfilter: h323: avoid potential attack Date: Wed, 27 Jan 2016 22:40:45 +0800 Message-ID: <1453905646-6446-1-git-send-email-zhouzhouyi@gmail.com> Cc: Zhouyi Zhou , Zhouyi Zhou To: , , , , , , , Return-path: Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org From: Zhouyi Zhou 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 --- net/netfilter/nf_conntrack_h323_main.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index 9511af0..3b3dd8c 100644 --- a/net/netfilter/nf_conntrack_h323_main.c +++ b/net/netfilter/nf_conntrack_h323_main.c @@ -110,6 +110,10 @@ int (*nat_q931_hook) (struct sk_buff *skb, static DEFINE_SPINLOCK(nf_h323_lock); static char *h323_buffer; +#define CHECK_BOUND(p, n) do { \ + if (((p - h323_buffer) + n) > 65536) \ + return 0; \ +} while (0) static struct nf_conntrack_helper nf_conntrack_helper_h245; static struct nf_conntrack_helper nf_conntrack_helper_q931[]; @@ -247,6 +251,8 @@ static int get_h245_addr(struct nf_conn *ct, const unsigned char *data, return 0; } + CHECK_BOUND(p, len); + memcpy(addr, p, len); memset((void *)addr + len, 0, sizeof(*addr) - len); memcpy(port, p + len, sizeof(__be16)); @@ -669,6 +675,8 @@ int get_h225_addr(struct nf_conn *ct, unsigned char *data, return 0; } + CHECK_BOUND(p, len); + memcpy(addr, p, len); memset((void *)addr + len, 0, sizeof(*addr) - len); memcpy(port, p + len, sizeof(__be16)); -- 1.7.10.4