/**
* 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.
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);
new_cl = htp_parse_content_length(h->value);
if ((existing_cl == -1) || (new_cl == -1) || (existing_cl != new_cl)) {
// Ambiguous response C-L value.
htp_log(connp, HTP_LOG_MARK, HTP_LOG_ERROR, 0, "Ambiguous response C-L value");
bstr_free(h->name);
bstr_free(h->value);
free(h);
return HTP_ERROR;
}
// 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;
}
/**
* Generic response header line(s) processor, which assembles folded lines
* into a single buffer before invoking the parsing function.
*
* @param[in] connp
* @return HTP status
*/
int htp_process_response_header_generic(htp_connp_t *connp) {
bstr *tempstr = NULL;
unsigned char *data = NULL;
size_t len = 0;
// Parse header
htp_header_t *h = calloc(1, sizeof (htp_header_t));
if (h == NULL) return HTP_ERROR;
// Ensure we have the necessary header data in a single buffer
if (connp->out_header_line_index + 1 == connp->out_header_line_counter) {
// Single line
htp_header_line_t *hl = htp_list_get(connp->out_tx->response_header_lines,
connp->out_header_line_index);
if (hl == NULL) {
// Internal error
htp_log(connp, HTP_LOG_MARK, HTP_LOG_ERROR, 0,
"Process response header (generic): Internal error");
free(h);
return HTP_ERROR;
}
data = bstr_ptr(hl->line);
len = bstr_len(hl->line);
hl->header = h;
} else {
// Multiple lines (folded)
int i = 0;
for (i = connp->out_header_line_index; i < connp->out_header_line_counter; i++) {
htp_header_line_t *hl = htp_list_get(connp->out_tx->response_header_lines, i);
len += bstr_len(hl->line);
}
tempstr = bstr_alloc(len);
if (tempstr == NULL) {
htp_log(connp, HTP_LOG_MARK, HTP_LOG_ERROR, 0,
"Process reqsponse header (generic): Failed to allocate bstring of %d bytes", len);
free(h);
return HTP_ERROR;
}
for (i = connp->out_header_line_index; i < connp->out_header_line_counter; i++) {
htp_header_line_t *hl = htp_list_get(connp->out_tx->response_header_lines, i);
unsigned char *line = bstr_ptr(hl->line);
size_t llen = bstr_len(hl->line);
htp_chomp((unsigned char *)line, &llen);
bstr_add_mem_noex(tempstr, line, llen);
hl->header = h;
if (i != connp->out_header_line_index) {
hl->flags |= HTP_FIELD_FOLDED;
}
}
h->flags |= HTP_FIELD_FOLDED;
data = bstr_ptr(tempstr);
len = bstr_len(tempstr);
}
if (htp_parse_response_header_generic(connp, h, data, len) != HTP_OK) {
// Note: downstream responsible for error logging
bstr_free(tempstr);
free(h);
return HTP_ERROR;
}
// 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) {
// repeated header
int i = 0;
// TODO Do we want to keep a list of the headers that are
// allowed to be combined in this way?
// Add to 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);
bstr_free(tempstr);
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);
// replace the header references in all lines
for (i = connp->out_header_line_index; i < connp->out_header_line_counter; i++) {
htp_header_line_t *hl = htp_list_get(connp->out_tx->response_header_lines, i);
hl->header = h_existing;
}
// The header is no longer needed
bstr_free(h->name);
bstr_free(h->value);
free(h);
// Keep track of same-name headers
h_existing->flags |= HTP_FIELD_REPEATED;
} else {
// Add as a new header
htp_table_add(connp->out_tx->response_headers, h->name, h);
}
bstr_free(tempstr);
return HTP_OK;
}
