RRC: reset strbuf pointer after its use

While we are at it, let's add a partial dissection of
PLMN-IdentityWithOptionalMCC-r6 IE.

Bug: 14248
Change-Id: I20b76bc74c248914db21629f8ce77799fccb1612
Reviewed-on: https://code.wireshark.org/review/24661
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
Petri-Dish: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 41 insertions, 7 deletions

diff --git a/epan/dissectors/asn1/rrc/rrc.cnf b/epan/dissectors/asn1/rrc/rrc.cnf
index 213c2bd0aa..4837a7c887 100644
--- a/epan/dissectors/asn1/rrc/rrc.cnf
+++ b/epan/dissectors/asn1/rrc/rrc.cnf
@@ -780,21 +780,21 @@ HandoverFromUTRANCommand-GSM-r6-IEs/gsm-message/single-GSM-Message single-GSM-Me
   tvbuff_t* mcc_mnc_tvb;
 
   /* Reset the digits string in the private data struct */
-  /* Maximal length: 6 = 3 digits MCC + 3 digits MNC + trailing '\0'*/
+  /* Maximal length: 7 = 3 digits MCC + 3 digits MNC + trailing '\0' */
   mcc_mnc_strbuf = wmem_strbuf_sized_new(actx->pinfo->pool,7,7);
   private_data_set_digits_strbuf(actx, mcc_mnc_strbuf);
   /* Reset parsing failure flag*/
   private_data_set_digits_strbuf_parsing_failed_flag(actx, FALSE);
 %(DEFAULT_BODY)s
+  private_data_set_digits_strbuf(actx, NULL);
   /* Check for parsing errors */
   if(private_data_get_digits_strbuf_parsing_failed_flag(actx)) {
     return offset;
   }
 
-  /* Extracing the string collected in the strbuf */
+  /* Extracting the string collected in the strbuf */
   string_len = (guint32)wmem_strbuf_get_len(mcc_mnc_strbuf);
-  mcc_mnc_string = wmem_strdup(actx->pinfo->pool, wmem_strbuf_get_str(mcc_mnc_strbuf));
-  wmem_strbuf_truncate(mcc_mnc_strbuf, 0);
+  mcc_mnc_string = wmem_strbuf_finalize(mcc_mnc_strbuf);
 
   /* Creating TVB from extracted string*/
   mcc_mnc_tvb = tvb_new_child_real_data(tvb, (guint8*)mcc_mnc_string, string_len, string_len);
@@ -803,6 +803,40 @@ HandoverFromUTRANCommand-GSM-r6-IEs/gsm-message/single-GSM-Message single-GSM-Me
   /* Calling E.212 */
   dissect_e212_mcc_mnc_in_utf8_address(mcc_mnc_tvb, actx->pinfo, tree, 0);
 
+#.FN_BODY PLMN-IdentityWithOptionalMCC-r6
+  wmem_strbuf_t* mcc_mnc_strbuf;
+  guint32 string_len;
+  gchar* mcc_mnc_string;
+  tvbuff_t* mcc_mnc_tvb;
+
+  /* Reset the digits string in the private data struct */
+  /* Maximal length: 7 = 3 digits MCC + 3 digits MNC + trailing '\0' */
+  mcc_mnc_strbuf = wmem_strbuf_sized_new(actx->pinfo->pool,7,7);
+  private_data_set_digits_strbuf(actx, mcc_mnc_strbuf);
+  /* Reset parsing failure flag*/
+  private_data_set_digits_strbuf_parsing_failed_flag(actx, FALSE);
+%(DEFAULT_BODY)s
+  private_data_set_digits_strbuf(actx, NULL);
+  /* Check for parsing errors */
+  if(private_data_get_digits_strbuf_parsing_failed_flag(actx)) {
+    return offset;
+  }
+
+  /* Extracting the string collected in the strbuf */
+  string_len = (guint32)wmem_strbuf_get_len(mcc_mnc_strbuf);
+  if (string_len >= 5) {
+    /* optional MCC was present, we can call E.212 dissector */
+    /* if not present, we could apply the algorithm in 25.331 chapter 8.1.1.5 */
+    mcc_mnc_string = wmem_strbuf_finalize(mcc_mnc_strbuf);
+
+    /* Creating TVB from extracted string*/
+    mcc_mnc_tvb = tvb_new_child_real_data(tvb, (guint8*)mcc_mnc_string, string_len, string_len);
+    add_new_data_source(actx->pinfo, mcc_mnc_tvb, "MCC-MNC");
+
+    /* Calling E.212 */
+    dissect_e212_mcc_mnc_in_utf8_address(mcc_mnc_tvb, actx->pinfo, tree, 0);
+  }
+
 #.FN_BODY IMSI-GSM-MAP
   wmem_strbuf_t* imsi_strbuf;
   guint32 string_len;
@@ -815,15 +849,15 @@ HandoverFromUTRANCommand-GSM-r6-IEs/gsm-message/single-GSM-Message single-GSM-Me
   /* Reset parsing failure flag*/
   private_data_set_digits_strbuf_parsing_failed_flag(actx, FALSE);
 %(DEFAULT_BODY)s
+  private_data_set_digits_strbuf(actx, NULL);
   /* Check for parsing errors */
   if(private_data_get_digits_strbuf_parsing_failed_flag(actx)) {
     return offset;
   }
 
-  /* Extracing the string collected in the strbuf */
+  /* Extracting the string collected in the strbuf */
   string_len = (guint32)wmem_strbuf_get_len(imsi_strbuf);
-  imsi_string = wmem_strdup(actx->pinfo->pool, wmem_strbuf_get_str(imsi_strbuf));
-  wmem_strbuf_truncate(imsi_strbuf, 0);
+  imsi_string = wmem_strbuf_finalize(imsi_strbuf);
 
   /* Creating TVB from extracted string*/
   imsi_tvb = tvb_new_child_real_data(tvb, (guint8*)imsi_string, string_len, string_len);