Fix bug9931 'Encapsulated ethernet packets sometimes show invalid FCS'

This fixes part-1 of bug9931: the uninitialized use of a wtap_pkthdr
struct. The second part of the bug deals with dissectors calling
the Ethernet dissector for ecnapsulated Ethernet packets but using
the wrong dissector handle to do so. That's unrelated to the issue this
commit addresses, so I'm splitting them up.

Change-Id: I87be7b736f82dd74d8c261062f88143372b5344c
Reviewed-on: https://code.wireshark.org/review/848
Reviewed-by: Hadriel Kaplan <hadrielk@yahoo.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

file.c

@@ -4019,7 +4019,7 @@ cf_get_comment(capture_file *cf, const frame_data *fd)
     struct wtap_pkthdr phdr; /* Packet header */
     Buffer buf; /* Packet data */
 
-    phdr.opt_comment = NULL;
+    memset(&phdr, 0, sizeof(struct wtap_pkthdr));
 
     buffer_init(&buf, 1500);
     if (!cf_read_frame_r(cf, fd, &phdr, &buf))

frame_tvbuff.c

@@ -74,6 +74,8 @@ frame_cache(struct tvb_frame *frame_tvb)
 {
 	struct wtap_pkthdr phdr; /* Packet header */
 
+	memset(&phdr, 0, sizeof(struct wtap_pkthdr));
+
 	if (frame_tvb->buf == NULL) {
 		frame_tvb->buf = (struct Buffer *) g_malloc(sizeof(struct Buffer));
 

proto_hier_stats.c

@@ -143,6 +143,8 @@ process_frame(frame_data *frame, column_info *cinfo, ph_stats_t* ps)
 	Buffer				buf;
 	double				cur_time;
 
+	memset(&phdr, 0, sizeof(struct wtap_pkthdr));
+
 	/* Load the frame from the capture file */
 	buffer_init(&buf, 1500);
 	if (!cf_read_frame_r(&cfile, frame, &phdr, &buf))

reordercap.c

@@ -96,6 +96,8 @@ frame_write(FrameRecord_t *frame, wtap *wth, wtap_dumper *pdh, Buffer *buf,
     gchar  *err_info;
     struct wtap_pkthdr phdr;
 
+    memset(&phdr, 0, sizeof(struct wtap_pkthdr));
+
     DEBUG_PRINT("\nDumping frame (offset=%" G_GINT64_MODIFIER "u)\n",
                 frame->offset);
 

tshark.c

@@ -3064,6 +3064,8 @@ load_cap_file(capture_file *cf, char *save_file, int out_file_type,
   Buffer       buf;
   epan_dissect_t *edt = NULL;
 
+  memset(&phdr, 0, sizeof(struct wtap_pkthdr));
+
   shb_hdr = wtap_file_get_shb_info(cf->wth);
   idb_inf = wtap_file_get_idb_info(cf->wth);
 #ifdef PCAP_NG_DEFAULT

ui/gtk/packet_list_store.c

@@ -1102,6 +1102,8 @@ packet_list_dissect_and_cache_record(PacketList *packet_list, PacketListRecord *
 	g_return_if_fail(packet_list);
 	g_return_if_fail(PACKETLIST_IS_LIST(packet_list));
 
+	memset(&phdr, 0, sizeof(struct wtap_pkthdr));
+
 	fdata = record->fdata;
 
 	if (dissect_columns) {

ui/qt/packet_list_model.cpp

@@ -218,6 +218,8 @@ QVariant PacketListModel::data(const QModelIndex &index, int role) const
     else
         cinfo = NULL;
 
+    memset(&phdr, 0, sizeof(struct wtap_pkthdr));
+
     buffer_init(&buf, 1500);
     if (!cap_file_ || !cf_read_frame_r(cap_file_, fdata, &phdr, &buf)) {
         /*

ui/tap_export_pdu.c

@@ -48,6 +48,7 @@ export_pdu_packet(void *tapdata, packet_info *pinfo, epan_dissect_t *edt _U_, co
     int buffer_len;
     guint8 *packet_buf;
 
+    memset(&pkthdr, 0, sizeof(struct wtap_pkthdr));
     buffer_len = exp_pdu_data->tvb_captured_length + exp_pdu_data->tlv_buffer_len;
     packet_buf = (guint8 *)g_malloc(buffer_len);
 
@@ -64,13 +65,11 @@ export_pdu_packet(void *tapdata, packet_info *pinfo, epan_dissect_t *edt _U_, co
     pkthdr.len       = exp_pdu_data->tvb_reported_length + exp_pdu_data->tlv_buffer_len;
 
     pkthdr.pkt_encap = exp_pdu_tap_data->pkt_encap;
-    pkthdr.interface_id = 0;
-    pkthdr.presence_flags = 0;
     pkthdr.opt_comment = g_strdup(pinfo->pkt_comment);
-    pkthdr.drop_count = 0;
-    pkthdr.pack_flags = 0;
     pkthdr.presence_flags = WTAP_HAS_CAP_LEN|WTAP_HAS_INTERFACE_ID|WTAP_HAS_TS|WTAP_HAS_PACK_FLAGS;
 
+    /* XXX: should the pkthdr.pseudo_header be set to the pinfo's pseudo-header? */
+
     wtap_dump(exp_pdu_tap_data->wdh, &pkthdr, packet_buf, &err);
 
     g_free(packet_buf);

ui/text_import.c

@@ -520,16 +520,13 @@ write_current_packet (void)
             struct wtap_pkthdr pkthdr;
             int err;
 
+            memset(&pkthdr, 0, sizeof(struct wtap_pkthdr));
+
             pkthdr.ts.secs = (guint32)ts_sec;
             pkthdr.ts.nsecs = ts_usec * 1000;
             if (ts_fmt == NULL) { ts_usec++; }  /* fake packet counter */
             pkthdr.caplen = pkthdr.len = prefix_length + curr_offset + eth_trailer_length;
             pkthdr.pkt_encap = pcap_link_type;
-            pkthdr.interface_id = 0;
-            pkthdr.presence_flags = 0;
-            pkthdr.opt_comment = NULL;
-            pkthdr.drop_count = 0;
-            pkthdr.pack_flags = 0;
             pkthdr.pack_flags |= direction;
             pkthdr.presence_flags = WTAP_HAS_CAP_LEN|WTAP_HAS_INTERFACE_ID|WTAP_HAS_TS|WTAP_HAS_PACK_FLAGS;