Don't assume we have a protocol tree.

In the association_sanity_check_t structure:

Have separate flags to indicate whether we *have* an IE specifying an
FT AKM suite and whether we *have* an IE specifying a non-FT AKM suite.
Use those to decide whether to add an expert info, so we add it
regardless of whether we are building a protocol tree or not.

Set the protocol tree item for the first FT AKM suite and the first
non-FT AKM suite only if we have a protocol tree.

Bug: 13149
Change-Id: I16a3194017b34d8d2c9128364c2761d1c202969d
Reviewed-on: https://code.wireshark.org/review/18863
Reviewed-by: Guy Harris <guy@alum.mit.edu>

2 files changed, 10 insertions, 6 deletions

diff --git a/epan/dissectors/packet-ieee80211.c b/epan/dissectors/packet-ieee80211.c
index ed4b6e2ff1..563cd6caa2 100644
--- a/epan/dissectors/packet-ieee80211.c
+++ b/epan/dissectors/packet-ieee80211.c
@@ -10622,12 +10622,14 @@ dissect_rsn_ie(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
         guint32 akm_suite = tvb_get_ntohl(tvb, offset);
         if (akm_suite == 0x000FAC03 || akm_suite == 0x000FAC04 || akm_suite == 0x000FAC09) {
           /* This is an FT AKM suite */
-          if (association_sanity_check->rsn_first_ft_akm_suite == NULL) {
+          association_sanity_check->has_ft_akm_suite = TRUE;
+          if (association_sanity_check->rsn_first_ft_akm_suite == NULL && rsn_sub_akms_tree != NULL) {
             association_sanity_check->rsn_first_ft_akm_suite = rsn_sub_akms_tree->last_child;
           }
         } else {
           /* This is a non-FT AKM suite */
-          if (association_sanity_check->rsn_first_non_ft_akm_suite == NULL) {
+          association_sanity_check->has_non_ft_akm_suite = TRUE;
+          if (association_sanity_check->rsn_first_non_ft_akm_suite == NULL && rsn_sub_akms_tree != NULL) {
             association_sanity_check->rsn_first_non_ft_akm_suite = rsn_sub_akms_tree->last_child;
           }
         }
@@ -11082,7 +11084,7 @@ dissect_mobility_domain(proto_tree *tree, tvbuff_t *tvb, int offset,
                         guint32 tag_len, association_sanity_check_t *association_sanity_check)
 {
   if (association_sanity_check != NULL) {
-    association_sanity_check->association_has_mobility_domain_element = 1;
+    association_sanity_check->association_has_mobility_domain_element = TRUE;
   }
 
   if (tag_len < 3) {
@@ -16139,13 +16141,13 @@ ieee_80211_do_association_sanity_check(packet_info *pinfo, association_sanity_ch
 
   if (sanity_check->association_has_mobility_domain_element) {
     /* This is an FT association, warn about any non-FT AKM suites */
-    if (sanity_check->rsn_first_non_ft_akm_suite != NULL) {
+    if (sanity_check->has_non_ft_akm_suite) {
       expert_add_info_format(pinfo, sanity_check->rsn_first_non_ft_akm_suite, &ei_ieee80211_mismatched_akm_suite,
                              "Non-FT AKM suite is prohibited for FT association request");
     }
   } else {
     /* This is a non-FT association, warn about any FT AKM suites */
-    if (sanity_check->rsn_first_ft_akm_suite != NULL) {
+    if (sanity_check->has_ft_akm_suite) {
       expert_add_info_format(pinfo, sanity_check->rsn_first_ft_akm_suite, &ei_ieee80211_mismatched_akm_suite,
                              "FT AKM suite is prohibited for non-FT association request");
     }
diff --git a/epan/dissectors/packet-ieee80211.h b/epan/dissectors/packet-ieee80211.h
index f983038b81..54eb5b4ff2 100644
--- a/epan/dissectors/packet-ieee80211.h
+++ b/epan/dissectors/packet-ieee80211.h
@@ -32,7 +32,9 @@ extern "C" {
 #endif /* __cplusplus */
 
 typedef struct {
-  int association_has_mobility_domain_element;
+  gboolean association_has_mobility_domain_element;
+  gboolean has_ft_akm_suite;
+  gboolean has_non_ft_akm_suite;
   proto_node *rsn_first_ft_akm_suite;
   proto_node *rsn_first_non_ft_akm_suite;
 } association_sanity_check_t;