175 lines
4.5 KiB
C
175 lines
4.5 KiB
C
/* rfc7468.c
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*
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* Implements loading of files in the format specified by RFC 7468.
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include "rfc7468.h"
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#include "file_wrappers.h"
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#include "wtap-int.h"
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#include <wsutil/buffer.h>
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#include <glib.h>
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#include <string.h>
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static gboolean rfc7468_read_file(wtap *wth, FILE_T fh, wtap_rec *rec,
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Buffer *buf, int *err, gchar **err_info)
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{
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gint64 file_size;
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int packet_size;
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if ((file_size = wtap_file_size(wth, err)) == -1)
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return FALSE;
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if (file_size > G_MAXINT) {
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/*
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* Probably a corrupt capture file; don't blow up trying
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* to allocate space for an immensely-large packet.
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*/
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("rfc7468: File has %" G_GINT64_MODIFIER "d-byte packet, bigger than maximum of %u",
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file_size, G_MAXINT);
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return FALSE;
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}
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packet_size = (int)file_size;
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rec->rec_type = REC_TYPE_PACKET;
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rec->presence_flags = 0; /* yes, we have no bananas^Wtime stamp */
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rec->rec_header.packet_header.caplen = packet_size;
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rec->rec_header.packet_header.len = packet_size;
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rec->ts.secs = 0;
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rec->ts.nsecs = 0;
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return wtap_read_packet_bytes(fh, buf, packet_size, err, err_info);
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}
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/* 128 bytes should be enough to contain any line. Strictly speaking, 64 is
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enough, but we provide some leeway to accomodate nonconformant producers and
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trailing whitespace. The 2 extra bytes are for the trailing newline and NUL
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terminator. */
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#define MAX_LINE_LENGTH (128 + 2)
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static char *read_complete_text_line(char line[MAX_LINE_LENGTH], FILE_T fh, int *err, gchar **err_info)
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{
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char *line_end;
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if (!(line_end = file_getsp(line, MAX_LINE_LENGTH, fh))) {
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*err = file_error(fh, err_info);
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return NULL;
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}
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if (strlen(line) != (size_t)(line_end - line)) {
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*err = 0;
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return NULL;
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}
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if (line_end[-1] != '\n' && !file_eof(fh)) {
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*err = 0;
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return NULL;
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}
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return line_end;
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}
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static gboolean rfc7468_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
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{
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gint64 offset;
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*err = 0;
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offset = file_tell(wth->fh);
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/* there is only ever one packet */
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if (offset != 0)
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return FALSE;
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*data_offset = offset;
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return rfc7468_read_file(wth, wth->fh, &wth->rec, wth->rec_data, err, err_info);
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}
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static gboolean rfc7468_seek_read(wtap *wth, gint64 seek_off, wtap_rec *rec,
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Buffer *buf, int *err, gchar **err_info)
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{
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/* there is only one packet */
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if (seek_off > 0) {
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*err = 0;
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return FALSE;
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}
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if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
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return FALSE;
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return rfc7468_read_file(wth, wth->random_fh, rec, buf, err, err_info);
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}
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//
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// Arbitrary value - we don't want to read all of a huge non-RFC 7468 file
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// only to find no pre-encapsulation boundary.
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//
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#define MAX_EXPLANATORY_TEXT_LINES 20
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wtap_open_return_val rfc7468_open(wtap *wth, int *err, gchar **err_info)
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{
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gboolean found_preeb;
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static const char preeb_begin[] = "-----BEGIN ";
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char line[MAX_LINE_LENGTH];
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//
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// Skip up to MAX_EXPLANATORY_TEXT_LINES worth of lines that don't
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// look like pre-encapsulation boundaries.
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//
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found_preeb = FALSE;
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for (unsigned int i = 0; i < MAX_EXPLANATORY_TEXT_LINES; i++) {
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if (!read_complete_text_line(line, wth->fh, err, err_info)) {
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if (*err == 0 || *err == WTAP_ERR_SHORT_READ)
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return WTAP_OPEN_NOT_MINE;
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return WTAP_OPEN_ERROR;
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}
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// Does the line look like a pre-encapsulation boundary?
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if (memcmp(line, preeb_begin, sizeof preeb_begin - 1) == 0) {
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// Yes.
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found_preeb = TRUE;
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break;
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}
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}
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if (!found_preeb)
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return WTAP_OPEN_NOT_MINE;
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if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
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return WTAP_OPEN_ERROR;
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wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_RFC7468;
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wth->file_encap = WTAP_ENCAP_RFC7468;
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wth->snapshot_length = 0;
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wth->file_tsprec = WTAP_TSPREC_SEC;
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wth->subtype_read = rfc7468_read;
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wth->subtype_seek_read = rfc7468_seek_read;
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return WTAP_OPEN_MINE;
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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