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