diff --git a/lib/libifconfig/libifconfig_carp.c b/lib/libifconfig/libifconfig_carp.c
--- a/lib/libifconfig/libifconfig_carp.c
+++ b/lib/libifconfig/libifconfig_carp.c
@@ -55,7 +55,7 @@
 	{ .type = CARP_NL_STATE, .off = _OUT(carpr_state), .cb = snl_attr_get_uint32 },
 	{ .type = CARP_NL_ADVBASE, .off = _OUT(carpr_advbase), .cb = snl_attr_get_int32 },
 	{ .type = CARP_NL_ADVSKEW, .off = _OUT(carpr_advskew), .cb = snl_attr_get_int32 },
-	{ .type = CARP_NL_KEY, .off = _OUT(carpr_key), .cb = snl_attr_get_string },
+	{ .type = CARP_NL_KEY, .off = _OUT(carpr_key), .cb = snl_attr_copy_string, .arg_u32 = CARP_KEY_LEN },
 	{ .type = CARP_NL_ADDR, .off = _OUT(carpr_addr), .cb = snl_attr_get_in_addr },
 	{ .type = CARP_NL_ADDR6, .off = _OUT(carpr_addr6), .cb = snl_attr_get_in6_addr },
 };
@@ -176,6 +176,7 @@
 	    &carpr->carpr_addr);
 	snl_add_msg_attr(&nw, CARP_NL_ADDR6, sizeof(carpr->carpr_addr6),
 	    &carpr->carpr_addr6);
+	snl_add_msg_attr_string(&nw, CARP_NL_KEY, carpr->carpr_key);
 
 	hdr = snl_finalize_msg(&nw);
 	if (hdr == NULL) {
diff --git a/sys/netlink/netlink_snl.h b/sys/netlink/netlink_snl.h
--- a/sys/netlink/netlink_snl.h
+++ b/sys/netlink/netlink_snl.h
@@ -138,7 +138,12 @@
 	uint16_t		type;	/* Attribute type */
 	uint16_t		off;	/* field offset in the target structure */
 	snl_parse_attr_f	*cb;	/* parser function to call */
-	const void		*arg;	/* Optional argument parser */
+
+	/* Optional parser argument */
+	union {
+		const void		*arg;
+		const uint32_t		 arg_u32;
+	};
 };
 
 struct snl_hdr_parser {
@@ -588,6 +593,19 @@
 	return (true);
 }
 
+static inline bool
+snl_attr_copy_string(struct snl_state *ss, struct nlattr *nla,
+    const void *arg, void *target)
+{
+	char *tmp;
+
+	if (snl_attr_get_string(ss, nla, NULL, &tmp)) {
+		strlcpy(target, tmp, (size_t)arg);
+		return (true);
+	}
+	return (false);
+}
+
 static inline bool
 snl_attr_get_nested(struct snl_state *ss, struct nlattr *nla, const void *arg, void *target)
 {