/* packet-http-urlencoded.c * Routines for dissection of HTTP urlecncoded form, based on packet-text-media.c (C) Olivier Biot, 2004. * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #include #include #include "packet-media-type.h" void proto_register_http_urlencoded(void); void proto_reg_handoff_http_urlencoded(void); static dissector_handle_t form_urlencoded_handle; static int proto_urlencoded; static int hf_form_key; static int hf_form_value; static int ett_form_urlencoded; static int ett_form_keyvalue; static ws_mempbrk_pattern pbrk_key; static ws_mempbrk_pattern pbrk_value; static int get_form_key_value(wmem_allocator_t *pool, tvbuff_t *tvb, char **ptr, int offset, const ws_mempbrk_pattern *pbrk) { const int orig_offset = offset; int found_offset; uint8_t ch; char *tmp; int len; len = 0; while (tvb_reported_length_remaining(tvb, offset) > 0) { found_offset = tvb_ws_mempbrk_pattern_uint8(tvb, offset, -1, pbrk, &ch); if (found_offset == -1) { len += tvb_reported_length_remaining(tvb, offset); break; } len += (found_offset - offset); offset = found_offset; if (ch == '%') { if (tvb_reported_length_remaining(tvb, offset) < 2) { return -1; } offset++; ch = tvb_get_uint8(tvb, offset); if (ws_xton(ch) == -1) return -1; offset++; ch = tvb_get_uint8(tvb, offset); if (ws_xton(ch) == -1) return -1; } else if (ch != '+') { /* Key, matched '=', stop. */ break; } len++; offset++; } *ptr = tmp = (char*)wmem_alloc(pool, len + 1); tmp[len] = '\0'; len = 0; offset = orig_offset; while (tvb_reported_length_remaining(tvb, offset)) { found_offset = tvb_ws_mempbrk_pattern_uint8(tvb, offset, -1, pbrk, &ch); if (found_offset == -1) { tvb_memcpy(tvb, &tmp[len], offset, tvb_reported_length_remaining(tvb, offset)); offset = tvb_reported_length(tvb); break; } tvb_memcpy(tvb, &tmp[len], offset, found_offset - offset); len += (found_offset - offset); offset = found_offset; if (ch == '%') { uint8_t ch1, ch2; offset++; ch1 = tvb_get_uint8(tvb, offset); offset++; ch2 = tvb_get_uint8(tvb, offset); tmp[len] = ws_xton(ch1) << 4 | ws_xton(ch2); } else if (ch == '+') { tmp[len] = ' '; } else { /* Key, matched '=', stop */ break; } len++; offset++; } return offset; } static int dissect_form_urlencoded(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data) { proto_tree *url_tree; proto_tree *sub; proto_item *ti; int offset = 0, next_offset, end_offset; const char *data_name; media_content_info_t *content_info; tvbuff_t *sequence_tvb; data_name = pinfo->match_string; if (! (data_name && data_name[0])) { /* * No information from "match_string" */ content_info = (media_content_info_t *)data; if (content_info == NULL) { /* * No information from dissector data */ data_name = NULL; } else { data_name = content_info->media_str; if (! (data_name && data_name[0])) { /* * No information from dissector data */ data_name = NULL; } } } if (data_name) col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "(%s)", data_name); ti = proto_tree_add_item(tree, proto_urlencoded, tvb, 0, -1, ENC_NA); if (data_name) proto_item_append_text(ti, ": %s", data_name); url_tree = proto_item_add_subtree(ti, ett_form_urlencoded); while (tvb_reported_length_remaining(tvb, offset) > 0) { char *key, *value; char *key_decoded, *value_decoded; end_offset = tvb_find_uint8(tvb, offset, -1, '&'); if (end_offset == -1) { end_offset = (int)tvb_reported_length(tvb); } sub = proto_tree_add_subtree(url_tree, tvb, offset, end_offset - offset, ett_form_keyvalue, NULL, "Form item"); sequence_tvb = tvb_new_subset_length(tvb, 0, end_offset); next_offset = get_form_key_value(pinfo->pool, sequence_tvb, &key, offset, &pbrk_key); if (next_offset == -1) break; /* XXX: Only UTF-8 is conforming according to WHATWG, though we * ought to look for a "charset" parameter in media_str * to handle other encodings. * Our charset functions should probably return a boolean * indicating that replacement characters had to be used, * and that the string was not the expected encoding. */ key_decoded = get_utf_8_string(pinfo->pool, key, (int)strlen(key)); proto_tree_add_string(sub, hf_form_key, tvb, offset, next_offset - offset, key_decoded); proto_item_append_text(sub, ": \"%s\"", format_text(pinfo->pool, key, strlen(key))); offset = next_offset+1; next_offset = get_form_key_value(pinfo->pool, sequence_tvb, &value, offset, &pbrk_value); if (next_offset == -1) break; value_decoded = get_utf_8_string(pinfo->pool, value, (int)strlen(value)); proto_tree_add_string(sub, hf_form_value, tvb, offset, next_offset - offset, value_decoded); proto_item_append_text(sub, " = \"%s\"", format_text(pinfo->pool, value, strlen(value))); offset = next_offset+1; } return tvb_captured_length(tvb); } void proto_register_http_urlencoded(void) { static hf_register_info hf[] = { { &hf_form_key, { "Key", "urlencoded-form.key", FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_form_value, { "Value", "urlencoded-form.value", FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL } }, }; static int *ett[] = { &ett_form_urlencoded, &ett_form_keyvalue }; proto_urlencoded = proto_register_protocol("HTML Form URL Encoded", "URL Encoded Form Data", "urlencoded-form"); form_urlencoded_handle = register_dissector("urlencoded-form", dissect_form_urlencoded, proto_urlencoded); proto_register_field_array(proto_urlencoded, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); ws_mempbrk_compile(&pbrk_key, "%+="); ws_mempbrk_compile(&pbrk_value, "%+"); } void proto_reg_handoff_http_urlencoded(void) { dissector_add_string("media_type", "application/x-www-form-urlencoded", form_urlencoded_handle); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 8 * tab-width: 8 * indent-tabs-mode: t * End: * * vi: set shiftwidth=8 tabstop=8 noexpandtab: * :indentSize=8:tabSize=8:noTabs=false: */