Revert "Get rid of the per-capture_file wtap_rec and Buffer."

This reverts commit 9445403f9558901dc54c88754ff21795ea1803f3.

cf_select_packet frees the buffer backing the dissection result
(cf->edt) which results in use-after-frees when callers try to access
the contents. See for example this call trace:

* PacketList::selectionChanged
  * cf_select_packet(cap_file_, row)
  * frameSelected(row) -> ByteViewTab::selectedFrameChanged
    * addTab(source_name, get_data_source_tvb(source))

get_data_source_tvb returns the buffer that backs the dissection and
must remain valid even after dissection has completed. If this is not
done, then a possibly expensive redissection must be done in order to
populate the byte view. The temporary memory savings are not worth it.

Bug: 15683
Change-Id: Ia5ec2c7736cdebbac3c5bf46a4e2470c9236262d
Reviewed-on: https://code.wireshark.org/review/32758
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 3 insertions, 18 deletions

diff --git a/ui/qt/rtp_analysis_dialog.cpp b/ui/qt/rtp_analysis_dialog.cpp
index dab1b94a5c..bc54d70820 100644
--- a/ui/qt/rtp_analysis_dialog.cpp
+++ b/ui/qt/rtp_analysis_dialog.cpp
@@ -1558,24 +1558,15 @@ void RtpAnalysisDialog::findStreams()
 
     frame_data *fdata = cap_file_.capFile()->current_frame;
 
-    wtap_rec rec;
-    Buffer buf;
-    wtap_rec_init(&rec);
-    ws_buffer_init(&buf, 1500);
-    if (!cf_read_record(cap_file_.capFile(), fdata, &rec, &buf)) {
-        wtap_rec_cleanup(&rec);
-        ws_buffer_free(&buf);
-        close();
-        return;
-    }
+    if (!cf_read_record(cap_file_.capFile(), fdata)) close();
 
     epan_dissect_t edt;
 
     epan_dissect_init(&edt, cap_file_.capFile()->epan, TRUE, FALSE);
     epan_dissect_prime_with_dfilter(&edt, sfcode);
     epan_dissect_prime_with_hfid(&edt, hfid_rtp_ssrc);
-    epan_dissect_run(&edt, cap_file_.capFile()->cd_t, &rec,
-                     frame_tvbuff_new_buffer(&cap_file_.capFile()->provider, fdata, &buf),
+    epan_dissect_run(&edt, cap_file_.capFile()->cd_t, &cap_file_.capFile()->rec,
+                     frame_tvbuff_new_buffer(&cap_file_.capFile()->provider, fdata, &cap_file_.capFile()->buf),
                      fdata, NULL);
 
     /*
@@ -1584,8 +1575,6 @@ void RtpAnalysisDialog::findStreams()
      */
     if (!dfilter_apply_edt(sfcode, &edt)) {
         epan_dissect_cleanup(&edt);
-        wtap_rec_cleanup(&rec);
-        ws_buffer_free(&buf);
         dfilter_free(sfcode);
         err_str_ = tr("Please select an RTPv2 packet with an SSRC value");
         updateWidgets();
@@ -1605,8 +1594,6 @@ void RtpAnalysisDialog::findStreams()
     if (gp == NULL || gp->len == 0) {
         /* XXX - should not happen, as the filter includes rtp.ssrc */
         epan_dissect_cleanup(&edt);
-        wtap_rec_cleanup(&rec);
-        ws_buffer_free(&buf);
         err_str_ = tr("SSRC value not found.");
         updateWidgets();
         return;
@@ -1614,8 +1601,6 @@ void RtpAnalysisDialog::findStreams()
     fwd_statinfo_.id.ssrc = fvalue_get_uinteger(&((field_info *)gp->pdata[0])->value);
 
     epan_dissect_cleanup(&edt);
-    wtap_rec_cleanup(&rec);
-    ws_buffer_free(&buf);
 
     /* Register the tap listener */
     memset(&tapinfo_, 0, sizeof(rtpstream_tapinfo_t));