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 <yizhouzhou@xxxxxxxxx> --- 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 -- 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
