dumpcap: fix uninitialized memory read on dumpcap -d errors

Reproduce with: dumpcap -pdf bad

Change-Id: I8c1f80c9d88262bc57651e886740083ea8e6ad52
Fixes: 4d6cb744df ("Add a "-d" flag to dumpcap")
Reviewed-on: https://code.wireshark.org/review/33863
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/dumpcap.c b/dumpcap.c
index 0492b07ac0..374300b208 100644
--- a/dumpcap.c
+++ b/dumpcap.c
@@ -758,6 +758,7 @@ show_filter_code(capture_options *capture_opts)
         /* OK, try to compile the capture filter. */
         if (!compile_capture_filter(interface_opts->name, pcap_h, &fcode,
                                     interface_opts->cfilter)) {
+            g_snprintf(errmsg, sizeof(errmsg), "%s", pcap_geterr(pcap_h));
             pcap_close(pcap_h);
             report_cfilter_error(capture_opts, j, errmsg);
             return FALSE;