Fix possible segmentation fault.

PR:		203494
MFC after:	1 week

diff --git a/sbin/ipfw/ipfw2.c b/sbin/ipfw/ipfw2.c
index 8ad8f90cc3176c43381ad74b248d8f89036c78aa..bc8af9f833a64b1777cd2bce68eddb686fa30b0b 100644 (file)
--- a/sbin/ipfw/ipfw2.c
+++ b/sbin/ipfw/ipfw2.c
@@ -3625,7 +3625,7 @@ compile_rule(char *av[], uint32_t *rbuf, int *rbufsize, struct tidx *tstate)
                action->opcode = O_NAT;
                action->len = F_INSN_SIZE(ipfw_insn_nat);
                CHECK_ACTLEN;
-               if (_substrcmp(*av, "global") == 0) {
+               if (*av != NULL && _substrcmp(*av, "global") == 0) {
                        action->arg1 = 0;
                        av++;
                        break;