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Diffstat (limited to 'htp/htp_response_generic.c')
| -rw-r--r-- | htp/htp_response_generic.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/htp/htp_response_generic.c b/htp/htp_response_generic.c new file mode 100644 index 0000000..f5fa59e --- /dev/null +++ b/htp/htp_response_generic.c @@ -0,0 +1,334 @@ +/*************************************************************************** + * Copyright (c) 2009-2010 Open Information Security Foundation + * Copyright (c) 2010-2013 Qualys, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + + * - Neither the name of the Qualys, Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + ***************************************************************************/ + +/** + * @file + * @author Ivan Ristic <ivanr@webkreator.com> + */ + +#include "htp_config_auto.h" + +#include "htp_private.h" + +/** + * Generic response line parser. + * + * @param[in] connp + * @return HTP status + */ +htp_status_t htp_parse_response_line_generic(htp_connp_t *connp) { + htp_tx_t *tx = connp->out_tx; + unsigned char *data = bstr_ptr(tx->response_line); + size_t len = bstr_len(tx->response_line); + size_t pos = 0; + + tx->response_protocol = NULL; + tx->response_protocol_number = HTP_PROTOCOL_INVALID; + tx->response_status = NULL; + tx->response_status_number = HTP_STATUS_INVALID; + tx->response_message = NULL; + + // Ignore whitespace at the beginning of the line. + while ((pos < len) && (htp_is_space(data[pos]))) pos++; + + size_t start = pos; + + // Find the end of the protocol string. + while ((pos < len) && (!htp_is_space(data[pos]))) pos++; + if (pos - start == 0) return HTP_OK; + + tx->response_protocol = bstr_dup_mem(data + start, pos - start); + if (tx->response_protocol == NULL) return HTP_ERROR; + + tx->response_protocol_number = htp_parse_protocol(tx->response_protocol); + + #ifdef HTP_DEBUG + fprint_raw_data(stderr, "Response protocol", bstr_ptr(tx->response_protocol), bstr_len(tx->response_protocol)); + fprintf(stderr, "Response protocol number: %d\n", tx->response_protocol_number); + #endif + + // Ignore whitespace after the response protocol. + while ((pos < len) && (htp_is_space(data[pos]))) pos++; + if (pos == len) return HTP_OK; + + start = pos; + + // Find the next whitespace character. + while ((pos < len) && (!htp_is_space(data[pos]))) pos++; + if (pos - start == 0) return HTP_OK; + + tx->response_status = bstr_dup_mem(data + start, pos - start); + if (tx->response_status == NULL) return HTP_ERROR; + + tx->response_status_number = htp_parse_status(tx->response_status); + + #ifdef HTP_DEBUG + fprint_raw_data(stderr, "Response status (as text)", bstr_ptr(tx->response_status), bstr_len(tx->response_status)); + fprintf(stderr, "Response status number: %d\n", tx->response_status_number); + #endif + + // Ignore whitespace that follows the status code. + while ((pos < len) && (isspace(data[pos]))) pos++; + if (pos == len) return HTP_OK; + + // Assume the message stretches until the end of the line. + tx->response_message = bstr_dup_mem(data + pos, len - pos); + if (tx->response_message == NULL) return HTP_ERROR; + + #ifdef HTP_DEBUG + fprint_raw_data(stderr, "Response status message", bstr_ptr(tx->response_message), bstr_len(tx->response_message)); + #endif + + return HTP_OK; +} + +/** + * Generic response header parser. + * + * @param[in] connp + * @param[in] h + * @param[in] data + * @param[in] len + * @return HTP status + */ +htp_status_t htp_parse_response_header_generic(htp_connp_t *connp, htp_header_t *h, unsigned char *data, size_t len) { + size_t name_start, name_end; + size_t value_start, value_end; + size_t prev; + + htp_chomp(data, &len); + + name_start = 0; + + // Look for the first colon. + size_t colon_pos = 0; + while ((colon_pos < len) && (data[colon_pos] != ':')) colon_pos++; + + if (colon_pos == len) { + // Header line with a missing colon. + + h->flags |= HTP_FIELD_UNPARSEABLE; + h->flags |= HTP_FIELD_INVALID; + + if (!(connp->out_tx->flags & HTP_FIELD_UNPARSEABLE)) { + // Only once per transaction. + connp->out_tx->flags |= HTP_FIELD_UNPARSEABLE; + connp->out_tx->flags |= HTP_FIELD_INVALID; + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Response field invalid: missing colon."); + } + + // Reset the position. We're going to treat this invalid header + // as a header with an empty name. That will increase the probability + // that the content will be inspected. + colon_pos = 0; + (void)colon_pos; // suppress scan-build warning + name_end = 0; + value_start = 0; + } else { + // Header line with a colon. + + if (colon_pos == 0) { + // Empty header name. + + h->flags |= HTP_FIELD_INVALID; + + if (!(connp->out_tx->flags & HTP_FIELD_INVALID)) { + // Only once per transaction. + connp->out_tx->flags |= HTP_FIELD_INVALID; + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Response field invalid: empty name."); + } + } + + name_end = colon_pos; + + // Ignore unprintable after field-name. + prev = name_end; + while ((prev > name_start) && htp_is_space(data[prev - 1])) { + prev--; + name_end--; + + h->flags |= HTP_FIELD_INVALID; + + if (!(connp->out_tx->flags & HTP_FIELD_INVALID)) { + // Only once per transaction. + connp->out_tx->flags |= HTP_FIELD_INVALID; + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Response field invalid: LWS after name."); + } + } + + value_start = colon_pos + 1; + } + + // Header value. + + // Ignore LWS before field-content. + while ((value_start < len) && (htp_is_lws(data[value_start]))) { + value_start++; + } + + // Look for the end of field-content. + value_end = len; + + // Check that the header name is a token. + size_t i = name_start; + while (i < name_end) { + if (!htp_is_token(data[i])) { + h->flags |= HTP_FIELD_INVALID; + + if (!(connp->out_tx->flags & HTP_FIELD_INVALID)) { + connp->out_tx->flags |= HTP_FIELD_INVALID; + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Response header name is not a token."); + } + + break; + } + + i++; + } + for (i = value_start; i < value_end; i++) { + if (data[i] == 0) { + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Response header value contains null."); + break; + } + } + // Ignore LWS after field-content. + prev = value_end - 1; + while ((prev > value_start) && (htp_is_lws(data[prev]))) { + prev--; + value_end--; + } + + // Now extract the name and the value. + h->name = bstr_dup_mem(data + name_start, name_end - name_start); + h->value = bstr_dup_mem(data + value_start, value_end - value_start); + if ((h->name == NULL) || (h->value == NULL)) { + bstr_free(h->name); + bstr_free(h->value); + return HTP_ERROR; + } + + return HTP_OK; +} + +/** + * Generic response header line(s) processor, which assembles folded lines + * into a single buffer before invoking the parsing function. + * + * @param[in] connp + * @param[in] data + * @param[in] len + * @return HTP status + */ +htp_status_t htp_process_response_header_generic(htp_connp_t *connp, unsigned char *data, size_t len) { + // Create a new header structure. + htp_header_t *h = calloc(1, sizeof (htp_header_t)); + if (h == NULL) return HTP_ERROR; + + if (htp_parse_response_header_generic(connp, h, data, len) != HTP_OK) { + free(h); + return HTP_ERROR; + } + + #ifdef HTP_DEBUG + fprint_bstr(stderr, "Header name", h->name); + fprint_bstr(stderr, "Header value", h->value); + #endif + + // Do we already have a header with the same name? + htp_header_t *h_existing = htp_table_get(connp->out_tx->response_headers, h->name); + if (h_existing != NULL) { + // Keep track of repeated same-name headers. + if ((h_existing->flags & HTP_FIELD_REPEATED) == 0) { + // This is the second occurence for this header. + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Repetition for header"); + } else { + // For simplicity reasons, we count the repetitions of all headers + if (connp->out_tx->res_header_repetitions < HTP_MAX_HEADERS_REPETITIONS) { + connp->out_tx->res_header_repetitions++; + } else { + bstr_free(h->name); + bstr_free(h->value); + free(h); + return HTP_OK; + } + } + h_existing->flags |= HTP_FIELD_REPEATED; + + // Having multiple C-L headers is against the RFC but many + // browsers ignore the subsequent headers if the values are the same. + if (bstr_cmp_c_nocase(h->name, "Content-Length") == 0) { + // Don't use string comparison here because we want to + // ignore small formatting differences. + + int64_t existing_cl, new_cl; + + existing_cl = htp_parse_content_length(h_existing->value, NULL); + new_cl = htp_parse_content_length(h->value, NULL); + if ((existing_cl == -1) || (new_cl == -1) || (existing_cl != new_cl)) { + // Ambiguous response C-L value. + htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Ambiguous response C-L value"); + } + + // Ignoring the new C-L header that has the same value as the previous ones. + } else { + // Add to the existing header. + + bstr *new_value = bstr_expand(h_existing->value, bstr_len(h_existing->value) + 2 + bstr_len(h->value)); + if (new_value == NULL) { + bstr_free(h->name); + bstr_free(h->value); + free(h); + return HTP_ERROR; + } + + h_existing->value = new_value; + bstr_add_mem_noex(h_existing->value, (unsigned char *) ", ", 2); + bstr_add_noex(h_existing->value, h->value); + } + + // The new header structure is no longer needed. + bstr_free(h->name); + bstr_free(h->value); + free(h); + } else { + // Add as a new header. + if (htp_table_add(connp->out_tx->response_headers, h->name, h) != HTP_OK) { + bstr_free(h->name); + bstr_free(h->value); + free(h); + return HTP_ERROR; + } + } + + return HTP_OK; +} |