1 files changed, 462 insertions, 0 deletions
diff --git a/htp/htp_request_generic.c b/htp/htp_request_generic.c
new file mode 100644
index 0000000..435cf0a
--- /dev/null
+++ b/htp/htp_request_generic.c
@@ -0,0 +1,462 @@
+/***************************************************************************
+ * 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"
+
+/**
+ * Extract one request header. A header can span multiple lines, in
+ * which case they will be folded into one before parsing is attempted.
+ *
+ * @param[in] connp
+ * @param[in] data
+ * @param[in] len
+ * @return HTP_OK or HTP_ERROR
+ */
+htp_status_t htp_process_request_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;
+
+    // Now try to parse the header.
+    if (htp_parse_request_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->in_tx->request_headers, h->name);
+    if (h_existing != NULL) {
+        // TODO Do we want to have a list of the headers that are
+        //      allowed to be combined in this way?
+        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->in_tx->req_header_repetitions < HTP_MAX_HEADERS_REPETITIONS) {
+                connp->in_tx->req_header_repetitions++;
+            } else {
+                bstr_free(h->name);
+                bstr_free(h->value);
+                free(h);
+                return HTP_OK;
+            }
+        }
+        // Keep track of repeated same-name headers.
+        h_existing->flags |= HTP_FIELD_REPEATED;
+
+        // Having multiple C-L headers is against the RFC but
+        // servers may 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 = htp_parse_content_length(h_existing->value, NULL);
+            int64_t new_cl = htp_parse_content_length(h->value, NULL);
+            // Ambiguous response C-L value.
+            if ((existing_cl == -1) || (new_cl == -1) || (existing_cl != new_cl)) {
+                htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Ambiguous request 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, ", ", 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->in_tx->request_headers, h->name, h) != HTP_OK) {
+            bstr_free(h->name);
+            bstr_free(h->value);
+            free(h);
+        }
+    }
+
+    return HTP_OK;
+}
+
+/**
+ * Generic request header parser.
+ *
+ * @param[in] connp
+ * @param[in] h
+ * @param[in] data
+ * @param[in] len
+ * @return HTP_OK or HTP_ERROR
+ */
+htp_status_t htp_parse_request_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;
+
+    htp_chomp(data, &len);
+
+    name_start = 0;
+
+    // Look for the colon.
+    size_t colon_pos = 0;
+    while ((colon_pos < len) && (data[colon_pos] != '\0') && (data[colon_pos] != ':')) colon_pos++;
+
+    if ((colon_pos == len) || (data[colon_pos] == '\0')) {
+        // Missing colon.
+
+        h->flags |= HTP_FIELD_UNPARSEABLE;
+
+        // Log only once per transaction.
+        if (!(connp->in_tx->flags & HTP_FIELD_UNPARSEABLE)) {
+            connp->in_tx->flags |= HTP_FIELD_UNPARSEABLE;
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request field invalid: colon missing");
+        }
+
+        // We handle this case as a header with an empty name, with the value equal
+        // to the entire input string.
+
+        // TODO Apache will respond to this problem with a 400.
+
+        // Now extract the name and the value
+        h->name = bstr_dup_c("");
+        if (h->name == NULL) return HTP_ERROR;
+
+        h->value = bstr_dup_mem(data, len);
+        if (h->value == NULL) {
+            bstr_free(h->name);
+            return HTP_ERROR;
+        }
+
+        return HTP_OK;
+    }
+
+    if (colon_pos == 0) {
+        // Empty header name.
+
+        h->flags |= HTP_FIELD_INVALID;
+
+        // Log only once per transaction.
+        if (!(connp->in_tx->flags & HTP_FIELD_INVALID)) {
+            connp->in_tx->flags |= HTP_FIELD_INVALID;
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request field invalid: empty name");
+        }
+    }
+
+    name_end = colon_pos;
+
+    // Ignore LWS after field-name.
+    size_t prev = name_end;
+    while ((prev > name_start) && (htp_is_lws(data[prev - 1]))) {
+        // LWS after header name.
+
+        prev--;
+        name_end--;
+
+        h->flags |= HTP_FIELD_INVALID;
+
+        // Log only once per transaction.
+        if (!(connp->in_tx->flags & HTP_FIELD_INVALID)) {
+            connp->in_tx->flags |= HTP_FIELD_INVALID;
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request field invalid: LWS after name");
+        }
+    }
+
+    // Header value.
+
+    value_start = colon_pos;
+
+    // Go over the colon.
+    if (value_start < len) {
+        value_start++;
+    }
+
+    // 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;
+
+    // Ignore LWS after field-content.
+    prev = value_end - 1;
+    while ((prev > value_start) && (htp_is_lws(data[prev]))) {
+        prev--;
+        value_end--;
+    }
+
+    // Check that the header name is a token.
+    size_t i = name_start;
+    while (i < name_end) {
+        if (!htp_is_token(data[i])) {
+            // Incorrectly formed header name.
+
+            h->flags |= HTP_FIELD_INVALID;
+
+            // Log only once per transaction.
+            if (!(connp->in_tx->flags & HTP_FIELD_INVALID)) {
+                connp->in_tx->flags |= HTP_FIELD_INVALID;
+                htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request header name is not a token");
+            }
+
+            break;
+        }
+
+        i++;
+    }
+
+    // Now extract the name and the value
+    h->name = bstr_dup_mem(data + name_start, name_end - name_start);
+    if (h->name == NULL) return HTP_ERROR;
+
+    h->value = bstr_dup_mem(data + value_start, value_end - value_start);
+    if (h->value == NULL) {
+        bstr_free(h->name);
+        return HTP_ERROR;
+    }
+
+    return HTP_OK;
+}
+
+/**
+ * Generic request line parser.
+ *
+ * @param[in] connp
+ * @return HTP_OK or HTP_ERROR
+ */
+htp_status_t htp_parse_request_line_generic(htp_connp_t *connp) {
+    return htp_parse_request_line_generic_ex(connp, 0 /* NUL does not terminates line */);
+}
+
+htp_status_t htp_parse_request_line_generic_ex(htp_connp_t *connp, int nul_terminates) {
+    htp_tx_t *tx = connp->in_tx;
+    unsigned char *data = bstr_ptr(tx->request_line);
+    size_t len = bstr_len(tx->request_line);
+    size_t pos = 0;
+    size_t mstart = 0;
+    size_t start;
+    size_t bad_delim;
+
+    if (nul_terminates) {
+        // The line ends with the first NUL byte.
+        
+        size_t newlen = 0;
+        while ((pos < len) && (data[pos] != '\0')) {
+            pos++;
+            newlen++;
+        }
+
+        // Start again, with the new length.
+        len = newlen;
+        pos = 0;
+    }
+
+    // skip past leading whitespace. IIS allows this
+    while ((pos < len) && htp_is_space(data[pos])) pos++;
+    if (pos) {
+        htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: leading whitespace");
+        mstart = pos;
+
+        if (connp->cfg->requestline_leading_whitespace_unwanted != HTP_UNWANTED_IGNORE) {
+            // reset mstart so that we copy the whitespace into the method
+            mstart = 0;
+            // set expected response code to this anomaly
+            tx->response_status_expected_number = connp->cfg->requestline_leading_whitespace_unwanted;
+        }
+    }
+
+    // The request method starts at the beginning of the
+    // line and ends with the first whitespace character.
+    while ((pos < len) && (!htp_is_space(data[pos]))) pos++;
+
+    // No, we don't care if the method is empty.
+
+    tx->request_method = bstr_dup_mem(data + mstart, pos - mstart);
+    if (tx->request_method == NULL) return HTP_ERROR;
+
+    #ifdef HTP_DEBUG
+    fprint_raw_data(stderr, __func__, bstr_ptr(tx->request_method), bstr_len(tx->request_method));
+    #endif
+
+    tx->request_method_number = htp_convert_method_to_number(tx->request_method);
+
+    bad_delim = 0;
+    // Ignore whitespace after request method. The RFC allows
+    // for only one SP, but then suggests any number of SP and HT
+    // should be permitted. Apache uses isspace(), which is even
+    // more permitting, so that's what we use here.
+    while ((pos < len) && (isspace(data[pos]))) {
+        if (!bad_delim && data[pos] != 0x20) {
+            bad_delim++;
+        }
+        pos++;
+    }
+// Too much performance overhead for fuzzing
+#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+    if (bad_delim) {
+        htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: non-compliant delimiter between Method and URI");
+    }
+#endif
+
+    // Is there anything after the request method?
+    if (pos == len) {
+        // No, this looks like a HTTP/0.9 request.
+
+        tx->is_protocol_0_9 = 1;
+        tx->request_protocol_number = HTP_PROTOCOL_0_9;
+        if (tx->request_method_number == HTP_M_UNKNOWN)
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: unknown method only");
+
+        return HTP_OK;
+    }
+
+    start = pos;
+    bad_delim = 0;
+    if (tx->connp->cfg->allow_space_uri) {
+        pos = len - 1;
+        // Skips the spaces at the end of line (after protocol)
+        while (pos > start && htp_is_space(data[pos])) pos--;
+        // The URI ends with the last whitespace.
+        while ((pos > start) && (data[pos] != 0x20)) {
+            if (!bad_delim && htp_is_space(data[pos])) {
+                bad_delim++;
+            }
+            pos--;
+        }
+        /* if we've seen some 'bad' delimiters, we retry with those */
+        if (bad_delim && pos == start) {
+            // special case: even though RFC's allow only SP (0x20), many
+            // implementations allow other delimiters, like tab or other
+            // characters that isspace() accepts.
+            pos = len - 1;
+            while ((pos > start) && (!htp_is_space(data[pos]))) pos--;
+        } else {
+            // reset bad_delim found in protocol part
+            bad_delim = 0;
+            for (size_t i = start; i < pos; i++) {
+                if (data[i] != 0x20 && htp_is_space(data[i])) {
+                    bad_delim = 1;
+                    break;
+                }
+            }
+        }
+        if (bad_delim) {
+#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+            // warn regardless if we've seen non-compliant chars
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: URI contains non-compliant delimiter");
+#endif
+        } else if (pos == start) {
+            pos = len;
+        }
+    } else {
+        // The URI ends with the first whitespace.
+        while ((pos < len) && (data[pos] != 0x20)) {
+            if (!bad_delim && htp_is_space(data[pos])) {
+                bad_delim++;
+            }
+            pos++;
+        }
+        /* if we've seen some 'bad' delimiters, we retry with those */
+        if (bad_delim && pos == len) {
+            // special case: even though RFC's allow only SP (0x20), many
+            // implementations allow other delimiters, like tab or other
+            // characters that isspace() accepts.
+            pos = start;
+            while ((pos < len) && (!htp_is_space(data[pos]))) pos++;
+        }
+#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+        if (bad_delim) {
+            // warn regardless if we've seen non-compliant chars
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: URI contains non-compliant delimiter");
+        }
+#endif
+    }
+
+    tx->request_uri = bstr_dup_mem(data + start, pos - start);
+    if (tx->request_uri == NULL) return HTP_ERROR;
+
+    #ifdef HTP_DEBUG
+    fprint_raw_data(stderr, __func__, bstr_ptr(tx->request_uri), bstr_len(tx->request_uri));
+    #endif
+
+    // Ignore whitespace after URI.
+    while ((pos < len) && (htp_is_space(data[pos]))) pos++;
+
+    // Is there protocol information available?
+    if (pos == len) {
+        // No, this looks like a HTTP/0.9 request.
+
+        tx->is_protocol_0_9 = 1;
+        tx->request_protocol_number = HTP_PROTOCOL_0_9;
+        if (tx->request_method_number == HTP_M_UNKNOWN)
+            htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: unknown method and no protocol");
+
+        return HTP_OK;
+    }
+
+    // The protocol information continues until the end of the line.
+    tx->request_protocol = bstr_dup_mem(data + pos, len - pos);
+    if (tx->request_protocol == NULL) return HTP_ERROR;
+
+    tx->request_protocol_number = htp_parse_protocol(tx->request_protocol);
+    if (tx->request_method_number == HTP_M_UNKNOWN && tx->request_protocol_number == HTP_PROTOCOL_INVALID)
+        htp_log(connp, HTP_LOG_MARK, HTP_LOG_WARNING, 0, "Request line: unknown method and invalid protocol");
+
+    #ifdef HTP_DEBUG
+    fprint_raw_data(stderr, __func__, bstr_ptr(tx->request_protocol), bstr_len(tx->request_protocol));
+    #endif
+
+    return HTP_OK;
+}
+