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-rw-r--r--epan/dissectors/packet-bencode.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/epan/dissectors/packet-bencode.c b/epan/dissectors/packet-bencode.c
new file mode 100644
index 00000000..1f893e4c
--- /dev/null
+++ b/epan/dissectors/packet-bencode.c
@@ -0,0 +1,338 @@
+/* packet-bencode.c
+ * Routines for bencode dissection
+ * Copyright (C) 2004,2013 Jelmer Vernooij <jelmer@samba.org>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * Copied from packet-pop.c
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/expert.h>
+#include <epan/strutil.h>
+
+void proto_register_bencode(void);
+
+static int proto_bencode = -1;
+
+static gint hf_bencode_str_length = -1;
+static gint hf_bencode_str = -1;
+static gint hf_bencode_int = -1;
+static gint hf_bencode_dict = -1;
+static gint hf_bencode_dict_entry = -1;
+static gint hf_bencode_list = -1;
+static gint hf_bencode_truncated_data = -1;
+
+static gint ett_bencode_dict = -1;
+static gint ett_bencode_dict_entry = -1;
+static gint ett_bencode_list = -1;
+
+static expert_field ei_bencode_str = EI_INIT;
+static expert_field ei_bencode_str_length = EI_INIT;
+static expert_field ei_bencode_int = EI_INIT;
+static expert_field ei_bencode_nest = EI_INIT;
+static expert_field ei_bencode_dict_key = EI_INIT;
+static expert_field ei_bencode_dict_value = EI_INIT;
+static expert_field ei_bencode_invalid = EI_INIT;
+
+static int dissect_bencoding_str(tvbuff_t *tvb, packet_info *pinfo,
+ int offset, int length, proto_tree *tree, proto_item *ti, int treeadd)
+{
+ guint8 ch;
+ int stringlen = 0, nextstringlen;
+ int used;
+ int izero = 0;
+
+ if (length < 2) {
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_str, tvb, offset, length);
+ return -1;
+ }
+
+ used = 0;
+
+ while (length >= 1) {
+ ch = tvb_get_guint8(tvb, offset + used);
+ length--;
+ used++;
+
+ if ((ch == ':') && (used > 1)) {
+ if ((stringlen > length) || (stringlen < 0)) {
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_str_length, tvb, offset, length);
+ return -1;
+ }
+ if (tree) {
+ proto_tree_add_uint(tree, hf_bencode_str_length, tvb, offset, used, stringlen);
+ proto_tree_add_item(tree, hf_bencode_str, tvb, offset + used, stringlen, ENC_ASCII);
+
+ if (treeadd == 1) {
+ proto_item_append_text(ti, " Key: %s",
+ tvb_format_text(pinfo->pool, tvb, offset + used, stringlen));
+ }
+ if (treeadd == 2) {
+ proto_item_append_text(ti, " Value: %s",
+ tvb_format_text(pinfo->pool, tvb, offset + used, stringlen));
+ }
+ }
+ return used + stringlen;
+ }
+
+ if (!izero && (ch >= '0') && (ch <= '9')) {
+ if ((ch == '0') && (used == 1)) {
+ izero = 1;
+ }
+
+ nextstringlen = (stringlen * 10) + (ch - '0');
+ if (nextstringlen >= stringlen) {
+ stringlen = nextstringlen;
+ continue;
+ }
+ }
+
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_str, tvb, offset, length);
+ return -1;
+ }
+
+ proto_tree_add_item(tree, hf_bencode_truncated_data, tvb, offset, length, ENC_NA);
+ return -1;
+}
+
+static int dissect_bencoding_int(tvbuff_t *tvb, packet_info *pinfo,
+ int offset, int length, proto_tree *tree, proto_item *ti, int treeadd)
+{
+ gint32 ival = 0;
+ int neg = 0;
+ int izero = 0;
+ int used;
+ guint8 ch;
+
+ if (length<3) {
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_int, tvb, offset, length);
+ return -1;
+ }
+
+ length--;
+ used = 1;
+
+ while (length >= 1) {
+ ch = tvb_get_guint8(tvb, offset + used);
+ length--;
+ used++;
+
+ switch (ch) {
+ case 'e':
+ if (tree) {
+ if (neg) ival = -ival;
+ proto_tree_add_int(tree, hf_bencode_int, tvb, offset, used, ival);
+ if (treeadd == 2) {
+ proto_item_append_text(ti, " Value: %d", ival);
+ }
+ }
+ return used;
+
+ case '-':
+ if (used == 2) {
+ neg = 1;
+ break;
+ }
+ /* Fall through */
+
+ default:
+ if (!((ch == '0') && (used == 3) && neg)) { /* -0 is invalid */
+ if ((ch == '0') && (used == 2)) { /* as is 0[0-9]+ */
+ izero = 1;
+ break;
+ }
+ if (!izero && (ch >= '0') && (ch <= '9')) {
+ ival = (ival * 10) + (ch - '0');
+ break;
+ }
+ }
+
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_int, tvb, offset, length);
+ return -1;
+ }
+ }
+
+ proto_tree_add_item(tree, hf_bencode_truncated_data, tvb, offset, length, ENC_NA);
+ return -1;
+}
+
+static int dissect_bencoding_rec(tvbuff_t *tvb, packet_info *pinfo,
+ int offset, int length, proto_tree *tree, int level, proto_item *treei, int treeadd)
+{
+ guint8 op;
+ int oplen = 0, op1len, op2len;
+ int used;
+
+ proto_item *ti = NULL, *td = NULL;
+ proto_tree *itree = NULL, *dtree = NULL;
+
+ if (level > 10) {
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_nest, tvb, offset, -1);
+ return -1;
+ }
+ if (length < 1) {
+ proto_tree_add_item(tree, hf_bencode_truncated_data, tvb, offset, -1, ENC_NA);
+ return length;
+ }
+
+ op = tvb_get_guint8(tvb, offset);
+ oplen = length;
+
+ switch (op) {
+ case 'd':
+ td = proto_tree_add_item(tree, hf_bencode_dict, tvb, offset, oplen, ENC_NA);
+ dtree = proto_item_add_subtree(td, ett_bencode_dict);
+
+ used = 1;
+ length--;
+
+ while (length >= 1) {
+ op = tvb_get_guint8(tvb, offset + used);
+
+ if (op == 'e') {
+ return used + 1;
+ }
+
+ op1len = dissect_bencoding_str(tvb, pinfo, offset + used, length, NULL, NULL, 0);
+ if (op1len < 0) {
+ proto_tree_add_expert(dtree, pinfo, &ei_bencode_dict_key, tvb, offset + used, -1);
+ return op1len;
+ }
+
+ op2len = -1;
+ if ((length - op1len) > 2)
+ op2len = dissect_bencoding_rec(tvb, pinfo, offset + used + op1len, length - op1len, NULL, level + 1, NULL, 0);
+ if (op2len < 0) {
+ proto_tree_add_expert(dtree, pinfo, &ei_bencode_dict_value, tvb, offset + used + op1len, -1);
+ return op2len;
+ }
+
+ ti = proto_tree_add_item(dtree, hf_bencode_dict_entry, tvb, offset + used, op1len + op2len, ENC_NA);
+ itree = proto_item_add_subtree(ti, ett_bencode_dict_entry);
+
+ dissect_bencoding_str(tvb, pinfo, offset + used, length, itree, ti, 1);
+ dissect_bencoding_rec(tvb, pinfo, offset + used + op1len, length - op1len, itree, level + 1, ti, 2);
+
+ used += op1len + op2len;
+ length -= op1len + op2len;
+ }
+
+ proto_tree_add_item(dtree, hf_bencode_truncated_data, tvb, offset + used, length ? -1 : 0, ENC_NA);
+ return -1;
+
+ case 'l':
+ ti = proto_tree_add_item(tree, hf_bencode_list, tvb, offset, oplen, ENC_NA);
+ itree = proto_item_add_subtree(ti, ett_bencode_list);
+
+ used = 1;
+ length--;
+
+ while (length >= 1) {
+ op = tvb_get_guint8(tvb, offset + used);
+
+ if (op == 'e') {
+ return used + 1;
+ }
+
+ oplen = dissect_bencoding_rec(tvb, pinfo, offset + used, length, itree, level + 1, ti, 0);
+ if (oplen < 1) return oplen;
+
+ used += oplen;
+ length -= oplen;
+ }
+
+ proto_tree_add_item(itree, hf_bencode_truncated_data, tvb, offset + used, -1, ENC_NA);
+ return -1;
+
+ case 'i':
+ return dissect_bencoding_int(tvb, pinfo, offset, length, tree, treei, treeadd);
+
+ default:
+ if ((op >= '1') && (op <= '9')) {
+ return dissect_bencoding_str(tvb, pinfo, offset, length, tree, treei, treeadd);
+ }
+
+ proto_tree_add_expert(tree, pinfo, &ei_bencode_invalid, tvb, offset, -1);
+ }
+
+ return -1;
+}
+
+static int dissect_bencoding(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+ dissect_bencoding_rec(tvb, pinfo, 0, tvb_reported_length(tvb), tree, 0, NULL, 0);
+ return tvb_captured_length(tvb);
+}
+
+void
+proto_register_bencode(void)
+{
+ static hf_register_info hf[] = {
+ { &hf_bencode_str_length,
+ { "String Length", "bencode.str.length", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL }
+ },
+ { &hf_bencode_str,
+ { "String", "bencode.str", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL }
+ },
+ { &hf_bencode_int,
+ { "Integer", "bencode.int", FT_INT32, BASE_DEC, NULL, 0x0, NULL, HFILL }
+ },
+ { &hf_bencode_dict,
+ { "Dictionary", "bencode.dict", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }
+ },
+ { &hf_bencode_dict_entry,
+ { "Entry", "bencode.dict.entry", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }
+ },
+ { &hf_bencode_list,
+ { "List", "bencode.list", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }
+ },
+ { &hf_bencode_truncated_data,
+ { "Truncated Data", "bencode.truncated_data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }
+ },
+ };
+
+ static gint *ett[] = {
+ &ett_bencode_dict,
+ &ett_bencode_dict_entry,
+ &ett_bencode_list,
+ };
+
+ static ei_register_info ei[] = {
+ { &ei_bencode_str, { "bencode.str.invalid", PI_MALFORMED, PI_ERROR, "Decode Aborted: Invalid String", EXPFILL }},
+ { &ei_bencode_str_length, { "bencode.str.length.invalid", PI_MALFORMED, PI_ERROR, "Decode Aborted: Invalid String Length", EXPFILL }},
+ { &ei_bencode_int, { "bencode.int.invalid", PI_MALFORMED, PI_ERROR, "Decode Aborted: Invalid Integer", EXPFILL }},
+ { &ei_bencode_nest, { "bencode.nest", PI_MALFORMED, PI_ERROR, "Decode Aborted: Nested Too Deep", EXPFILL }},
+ { &ei_bencode_dict_key, { "bencode.dict.key_invalid", PI_MALFORMED, PI_ERROR, "Decode Aborted: Invalid Dictionary Key", EXPFILL }},
+ { &ei_bencode_dict_value, { "bencode.dict.value_invalid", PI_MALFORMED, PI_ERROR, "Decode Aborted: Invalid Dictionary Value", EXPFILL }},
+ { &ei_bencode_invalid, { "bencode.invalid", PI_MALFORMED, PI_ERROR, "Invalid Bencoding", EXPFILL }},
+ };
+
+ expert_module_t* expert_bencode;
+
+ proto_bencode = proto_register_protocol("Bencode", "Bencode", "bencode");
+ register_dissector("bencode", dissect_bencoding, proto_bencode);
+ proto_register_field_array(proto_bencode, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+ expert_bencode = expert_register_protocol(proto_bencode);
+ expert_register_field_array(expert_bencode, ei, array_length(ei));
+}
+
+/*
+ * Editor modelines - https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 3
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=3 tabstop=8 expandtab:
+ * :indentSize=3:tabSize=8:noTabs=true:
+ */
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