diff options
| author | Peter Wu <peter@lekensteyn.nl> | 2017-11-24 00:05:05 +0000 |
|---|---|---|
| committer | Anders Broman <a.broman58@gmail.com> | 2017-11-24 05:20:49 +0000 |
| commit | 9ac02f18c981c175be83b41bded7462aef128a3d (patch) | |
| tree | c5146ae7e6d3c5e2e270762ab7bd5d29fa346b91 | |
| parent | b99677dea95a8886429574713d5a78dde9181959 (diff) | |
packet: ensure consistent layer number for heuristics dissector
DTLS decryption works for single-pass dissection, but breaks in the
second pass. Turns out that "curr_layer_num" has decremented in the
second pass, resulting in a failure to lookup the decrypted data.
This decryption issue was triggered by v2.3.0rc0-3740-ge1f84f985e
("Fix Decode As for protocols that may use tunneling.").
The first time the UDP dissector invokes "dissector_try_heuristic", the
second time "call_heur_dissector_direct". The first one increments
"curr_layer_num", so do the same in the second case.
Change-Id: I62679b817b02f42d073cfc07b88ec36d5bec5f04
Bug: 14243
Fixes: v1.11.4-rc1-468-g2cfda31ff0 ("Change the signature of dissector_try_heuristic() to return hdtbl_entry")
Reviewed-on: https://code.wireshark.org/review/24565
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Anders Broman <a.broman58@gmail.com>
| -rw-r--r-- | epan/packet.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/epan/packet.c b/epan/packet.c index 3904256d3c..7895610b5a 100644 --- a/epan/packet.c +++ b/epan/packet.c @@ -3102,6 +3102,7 @@ void call_heur_dissector_direct(heur_dtbl_entry_t *heur_dtbl_entry, tvbuff_t *tv const char *saved_curr_proto; const char *saved_heur_list_name; guint16 saved_can_desegment; + guint saved_layers_len = 0; g_assert(heur_dtbl_entry); @@ -3121,6 +3122,8 @@ void call_heur_dissector_direct(heur_dtbl_entry_t *heur_dtbl_entry, tvbuff_t *tv saved_curr_proto = pinfo->current_proto; saved_heur_list_name = pinfo->heur_list_name; + saved_layers_len = wmem_list_count(pinfo->layers); + if (!heur_dtbl_entry->enabled || (heur_dtbl_entry->protocol != NULL && !proto_is_protocol_enabled(heur_dtbl_entry->protocol))) { g_assert(data_handle->protocol != NULL); @@ -3132,15 +3135,27 @@ void call_heur_dissector_direct(heur_dtbl_entry_t *heur_dtbl_entry, tvbuff_t *tv /* do NOT change this behavior - wslua uses the protocol short name set here in order to determine which Lua-based heuristic dissector to call */ pinfo->current_proto = proto_get_protocol_short_name(heur_dtbl_entry->protocol); + pinfo->curr_layer_num++; wmem_list_append(pinfo->layers, GINT_TO_POINTER(proto_get_id(heur_dtbl_entry->protocol))); } pinfo->heur_list_name = heur_dtbl_entry->list_name; /* call the dissector, in case of failure call data handle (might happen with exported PDUs) */ - if(!(*heur_dtbl_entry->dissector)(tvb, pinfo, tree, data)) + if(!(*heur_dtbl_entry->dissector)(tvb, pinfo, tree, data)) { call_dissector_work(data_handle, tvb, pinfo, tree, TRUE, NULL); + /* + * We added a protocol layer above. The dissector + * didn't accept the packet or it didn't add any + * items to the tree so remove it from the list. + */ + while (wmem_list_count(pinfo->layers) > saved_layers_len) { + pinfo->curr_layer_num--; + wmem_list_remove_frame(pinfo->layers, wmem_list_tail(pinfo->layers)); + } + } + /* Restore info from caller */ pinfo->can_desegment = saved_can_desegment; pinfo->current_proto = saved_curr_proto; |