xnu-4903.221.2.tar.gz

[apple/xnu.git] / bsd / net / packet_mangler.c

diff --git a/bsd/net/packet_mangler.c b/bsd/net/packet_mangler.c
index a09e7c74c2321ba4185d649975f8d0f89842a8c4..24d18870ab4c5f336ace558172d2c9f9bb13c377 100644 (file)
--- a/bsd/net/packet_mangler.c
+++ b/bsd/net/packet_mangler.c
@@ -1068,6 +1068,7 @@ static void chksm_update(mbuf_t data)
        u_int16_t ip_sum;
        u_int16_t tsum;
        struct tcphdr *tcp;
+       errno_t err;
 
        unsigned char *ptr = (unsigned char *)mbuf_data(data);
        struct ip *ip = (struct ip *)(void *)ptr;
@@ -1076,16 +1077,17 @@ static void chksm_update(mbuf_t data)
        }
 
        ip->ip_sum = 0;
-       mbuf_inet_cksum(data, 0, 0, ip->ip_hl << 2, &ip_sum); // ip sum
-
-       ip->ip_sum = ip_sum;
+       err = mbuf_inet_cksum(data, 0, 0, ip->ip_hl << 2, &ip_sum); // ip sum
+       if (err == 0)
+               ip->ip_sum = ip_sum;
        switch (ip->ip_p) {
                case IPPROTO_TCP:
                        tcp = (struct tcphdr *)(void *)(ptr + (ip->ip_hl << 2));
                        tcp->th_sum = 0;
-                       mbuf_inet_cksum(data, IPPROTO_TCP, ip->ip_hl << 2,
+                       err = mbuf_inet_cksum(data, IPPROTO_TCP, ip->ip_hl << 2,
                            ntohs(ip->ip_len) - (ip->ip_hl << 2), &tsum);
-                       tcp->th_sum = tsum;
+                       if (err == 0)
+                               tcp->th_sum = tsum;
                        break;
                case IPPROTO_UDP:
                        /* Don't handle UDP */