diff options
| -rw-r--r-- | epan/dissectors/packet-http.c | 198 |
1 files changed, 145 insertions, 53 deletions
diff --git a/epan/dissectors/packet-http.c b/epan/dissectors/packet-http.c index e93e644c22..1a4ce6e6fa 100644 --- a/epan/dissectors/packet-http.c +++ b/epan/dissectors/packet-http.c @@ -138,7 +138,8 @@ static gint ett_http_encoded_entity = -1; static gint ett_http_header_item = -1; static expert_field ei_http_chat = EI_INIT; -static expert_field ei_http_chunked_and_length = EI_INIT; +static expert_field ei_http_te_and_length = EI_INIT; +static expert_field ei_http_te_unknown = EI_INIT; static expert_field ei_http_subdissector_failed = EI_INIT; static expert_field ei_http_ssl_port = EI_INIT; static expert_field ei_http_leading_crlf = EI_INIT; @@ -286,6 +287,21 @@ static range_t *http_ssl_range = NULL; typedef void (*ReqRespDissector)(tvbuff_t*, proto_tree*, int, const guchar*, const guchar*, http_conv_t *); +/** + * Transfer codings from + * https://www.iana.org/assignments/http-parameters/http-parameters.xhtml#transfer-coding + * Note: chunked encoding is handled separately. + */ +typedef enum _http_transfer_coding { + HTTP_TE_NONE, /* Dummy value for header which is not set */ + /* HTTP_TE_CHUNKED, */ + HTTP_TE_COMPRESS, + HTTP_TE_DEFLATE, + HTTP_TE_GZIP, + HTTP_TE_IDENTITY, + HTTP_TE_UNKNOWN, /* Header was set, but no valid name was found */ +} http_transfer_coding; + /* * Structure holding information from headers needed by main * HTTP dissector code. @@ -294,9 +310,10 @@ typedef struct { char *content_type; char *content_type_parameters; gboolean have_content_length; - gint64 content_length; - char *content_encoding; - char *transfer_encoding; + gint64 content_length; + char *content_encoding; + gboolean transfer_encoding_chunked; + http_transfer_coding transfer_encoding; guint8 upgrade; } headers_t; @@ -836,7 +853,8 @@ dissect_http_message(tvbuff_t *tvb, int offset, packet_info *pinfo, headers.have_content_length = FALSE; /* content length not known yet */ headers.content_length = 0; /* content length set to 0 (avoid a gcc warning) */ headers.content_encoding = NULL; /* content encoding not known yet */ - headers.transfer_encoding = NULL; /* transfer encoding not known yet */ + headers.transfer_encoding_chunked = FALSE; + headers.transfer_encoding = HTTP_TE_NONE; headers.upgrade = 0; /* assume we're not upgrading */ saw_req_resp_or_header = FALSE; /* haven't seen anything yet */ while (tvb_offset_exists(tvb, offset)) { @@ -1198,8 +1216,7 @@ dissect_http_message(tvbuff_t *tvb, int offset, packet_info *pinfo, * the response in order to handle that. */ if (headers.have_content_length && - headers.content_length != -1 && - headers.transfer_encoding == NULL) { + headers.transfer_encoding == HTTP_TE_NONE) { if (datalen > headers.content_length) datalen = (int)headers.content_length; @@ -1228,7 +1245,7 @@ dissect_http_message(tvbuff_t *tvb, int offset, packet_info *pinfo, * Content-Length header and no Transfer-Encoding * header. */ - if (headers.transfer_encoding == NULL) + if (headers.transfer_encoding == HTTP_TE_NONE) datalen = 0; else reported_datalen = -1; @@ -1285,51 +1302,60 @@ dissect_http_message(tvbuff_t *tvb, int offset, packet_info *pinfo, reported_datalen); /* - * Handle *transfer* encodings other than "identity". + * Handle *transfer* encodings. */ - if (headers.transfer_encoding != NULL && - g_ascii_strcasecmp(headers.transfer_encoding, "identity") != 0) { - if (http_dechunk_body && - (g_ascii_strncasecmp(headers.transfer_encoding, "chunked", 7) - == 0)) { + if (headers.transfer_encoding_chunked) { + if (!http_dechunk_body) { + /* Chunking disabled, cannot dissect further. */ + call_dissector(data_handle, next_tvb, pinfo, + http_tree); + goto body_dissected; + } - chunked_datalen = chunked_encoding_dissector( - &next_tvb, pinfo, http_tree, 0); + chunked_datalen = chunked_encoding_dissector( + &next_tvb, pinfo, http_tree, 0); - if (chunked_datalen == 0) { - /* - * The chunks weren't reassembled, - * or there was a single zero - * length chunk. - */ - goto body_dissected; - } else { - /* - * Add a new data source for the - * de-chunked data. - */ -#if 0 /* Handled in chunked_encoding_dissector() */ - tvb_set_child_real_data_tvbuff(tvb, - next_tvb); -#endif - add_new_data_source(pinfo, next_tvb, - "De-chunked entity body"); - /* chunked-body might be smaller than - * datalen. */ - datalen = chunked_datalen; - } - } else { + if (chunked_datalen == 0) { /* - * We currently can't handle, for example, - * "gzip", "compress", or "deflate" as - * *transfer* encodings; just handle them - * as data for now. + * The chunks weren't reassembled, + * or there was a single zero + * length chunk. */ - call_dissector(data_handle, next_tvb, pinfo, - http_tree); goto body_dissected; + } else { + /* + * Add a new data source for the + * de-chunked data. + */ +#if 0 /* Handled in chunked_encoding_dissector() */ + tvb_set_child_real_data_tvbuff(tvb, + next_tvb); +#endif + add_new_data_source(pinfo, next_tvb, + "De-chunked entity body"); + /* chunked-body might be smaller than + * datalen. */ + datalen = chunked_datalen; } } + /* Handle other transfer codings after de-chunking. */ + switch (headers.transfer_encoding) { + case HTTP_TE_COMPRESS: + case HTTP_TE_DEFLATE: + case HTTP_TE_GZIP: + break; + /* + * We currently can't handle, for example, "gzip", + * "compress", or "deflate" as *transfer* encodings; + * just handle them as data for now. + */ + call_dissector(data_handle, next_tvb, pinfo, http_tree); + goto body_dissected; + default: + /* Nothing to do for "identity" or when header is + * missing or invalid. */ + break; + } /* * At this point, any chunked *transfer* coding has been removed * (the entity body has been dechunked) so it can be presented @@ -2382,6 +2408,71 @@ header_fields_initialize_cb(void) } } +/** + * Parses the transfer-coding, returning TRUE if everything was fully understood + * or FALSE when unknown names were encountered. + */ +static gboolean +http_parse_transfer_coding(const char *value, headers_t *eh_ptr) +{ + gboolean is_fully_parsed = TRUE; + + /* Mark header as set, but with unknown encoding. */ + eh_ptr->transfer_encoding = HTTP_TE_UNKNOWN; + + while (*value) { + /* skip OWS (SP / HTAB) and commas; stop at the end. */ + while (*value == ' ' || *value == '\t' || *value == ',') + value++; + if (!*value) + break; + + if (g_str_has_prefix(value, "chunked")) { + eh_ptr->transfer_encoding_chunked = TRUE; + value += sizeof("chunked") - 1; + continue; + } + + /* For now assume that chunked can only combined with exactly + * one other (compression) encoding. Anything else is + * unsupported. */ + if (eh_ptr->transfer_encoding != HTTP_TE_UNKNOWN) { + /* No more transfer codings are expected. */ + is_fully_parsed = FALSE; + break; + } + + if (g_str_has_prefix(value, "compress")) { + eh_ptr->transfer_encoding = HTTP_TE_COMPRESS; + value += sizeof("compress") - 1; + } else if (g_str_has_prefix(value, "deflate")) { + eh_ptr->transfer_encoding = HTTP_TE_DEFLATE; + value += sizeof("deflate") - 1; + } else if (g_str_has_prefix(value, "gzip")) { + eh_ptr->transfer_encoding = HTTP_TE_GZIP; + value += sizeof("gzip") - 1; + } else if (g_str_has_prefix(value, "identity")) { + eh_ptr->transfer_encoding = HTTP_TE_IDENTITY; + value += sizeof("identity") - 1; + } else if (g_str_has_prefix(value, "x-compress")) { + eh_ptr->transfer_encoding = HTTP_TE_COMPRESS; + value += sizeof("x-compress") - 1; + } else if (g_str_has_prefix(value, "x-gzip")) { + eh_ptr->transfer_encoding = HTTP_TE_GZIP; + value += sizeof("x-gzip") - 1; + } else { + /* Unknown transfer encoding, skip until next comma. + * Stop when no more names are found. */ + is_fully_parsed = FALSE; + value = strchr(value, ','); + if (!value) + break; + } + } + + return is_fully_parsed; +} + static void process_header(tvbuff_t *tvb, int offset, int next_offset, const guchar *line, int linelen, int colon_offset, @@ -2617,9 +2708,8 @@ process_header(tvbuff_t *tvb, int offset, int next_offset, tree_item = proto_tree_add_uint64(header_tree, hf_http_content_length, tvb, offset, len, eh_ptr->content_length); PROTO_ITEM_SET_GENERATED(tree_item); - if (eh_ptr->transfer_encoding != NULL && - g_ascii_strncasecmp(eh_ptr->transfer_encoding, "chunked", 7) == 0) { - expert_add_info(pinfo, hdr_item, &ei_http_chunked_and_length); + if (eh_ptr->transfer_encoding != HTTP_TE_NONE) { + expert_add_info(pinfo, hdr_item, &ei_http_te_and_length); } } break; @@ -2629,10 +2719,11 @@ process_header(tvbuff_t *tvb, int offset, int next_offset, break; case HDR_TRANSFER_ENCODING: - eh_ptr->transfer_encoding = wmem_strndup(wmem_packet_scope(), value, value_len); - if (eh_ptr->have_content_length && - g_ascii_strncasecmp(eh_ptr->transfer_encoding, "chunked", 7) == 0) { - expert_add_info(pinfo, hdr_item, &ei_http_chunked_and_length); + if (eh_ptr->have_content_length) { + expert_add_info(pinfo, hdr_item, &ei_http_te_and_length); + } + if (!http_parse_transfer_coding(value, eh_ptr)) { + expert_add_info(pinfo, hdr_item, &ei_http_te_unknown); } break; @@ -3281,7 +3372,8 @@ proto_register_http(void) static ei_register_info ei[] = { { &ei_http_chat, { "http.chat", PI_SEQUENCE, PI_CHAT, "Formatted text", EXPFILL }}, - { &ei_http_chunked_and_length, { "http.chunkd_and_length", PI_MALFORMED, PI_WARN, "It is incorrect to specify a content-length header and chunked encoding together.", EXPFILL }}, + { &ei_http_te_and_length, { "http.te_and_length", PI_MALFORMED, PI_WARN, "The Content-Length and Transfer-Encoding header must not be set together", EXPFILL }}, + { &ei_http_te_unknown, { "http.te_unknown", PI_UNDECODED, PI_WARN, "Unknown transfer coding name in Transfer-Encoding header", EXPFILL }}, { &ei_http_subdissector_failed, { "http.subdissector_failed", PI_MALFORMED, PI_NOTE, "HTTP body subdissector failed, trying heuristic subdissector", EXPFILL }}, { &ei_http_ssl_port, { "http.ssl_port", PI_SECURITY, PI_WARN, "Unencrypted HTTP protocol detected over encrypted port, could indicate a dangerous misconfiguration.", EXPFILL }}, { &ei_http_leading_crlf, { "http.leading_crlf", PI_MALFORMED, PI_ERROR, "Leading CRLF previous message in the stream may have extra CRLF", EXPFILL }}, |