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/* mime_file.c
*
* MIME file format decoder for the Wiretap library.
*
* This is for use with Wireshark dissectors that handle file
* formats (e.g., because they handle a particular MIME media type).
* It breaks the file into chunks of at most WTAP_MAX_PACKET_SIZE_STANDARD,
* each of which is reported as a packet, so that files larger than
* WTAP_MAX_PACKET_SIZE_STANDARD can be handled by reassembly.
*
* The "MIME file" dissector does the reassembly, and hands the result
* off to heuristic dissectors to try to identify the file's contents.
*
* Wiretap Library
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "wtap-int.h"
#include "file_wrappers.h"
#include <wsutil/buffer.h>
#include "mime_file.h"
typedef struct {
const guint8 *magic;
guint magic_len;
} mime_files_t;
/*
* Written by Marton Nemeth <nm127@freemail.hu>
* Copyright 2009 Marton Nemeth
* The JPEG and JFIF specification can be found at:
*
* http://www.jpeg.org/public/jfif.pdf
* http://www.w3.org/Graphics/JPEG/itu-t81.pdf
*/
static const guint8 jpeg_jfif_magic[] = { 0xFF, 0xD8, /* SOF */
0xFF /* start of the next marker */
};
/* <?xml */
static const guint8 xml_magic[] = { '<', '?', 'x', 'm', 'l' };
static const guint8 png_magic[] = { 0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n' };
static const guint8 gif87a_magic[] = { 'G', 'I', 'F', '8', '7', 'a'};
static const guint8 gif89a_magic[] = { 'G', 'I', 'F', '8', '9', 'a'};
static const guint8 elf_magic[] = { 0x7F, 'E', 'L', 'F'};
static const guint8 btsnoop_magic[] = { 'b', 't', 's', 'n', 'o', 'o', 'p', 0};
static const guint8 pcap_magic[] = { 0xA1, 0xB2, 0xC3, 0xD4 };
static const guint8 pcap_swapped_magic[] = { 0xD4, 0xC3, 0xB2, 0xA1 };
static const guint8 pcapng_premagic[] = { 0x0A, 0x0D, 0x0D, 0x0A };
/* File does not start with it */
static const guint8 pcapng_xmagic[] = { 0x1A, 0x2B, 0x3C, 0x4D };
static const guint8 pcapng_swapped_xmagic[] = { 0x4D, 0x3C, 0x2B, 0x1A };
static const mime_files_t magic_files[] = {
{ jpeg_jfif_magic, sizeof(jpeg_jfif_magic) },
{ xml_magic, sizeof(xml_magic) },
{ png_magic, sizeof(png_magic) },
{ gif87a_magic, sizeof(gif87a_magic) },
{ gif89a_magic, sizeof(gif89a_magic) },
{ elf_magic, sizeof(elf_magic) },
{ btsnoop_magic, sizeof(btsnoop_magic) },
{ pcap_magic, sizeof(pcap_magic) },
{ pcap_swapped_magic, sizeof(pcap_swapped_magic) },
{ pcapng_premagic, sizeof(pcapng_premagic) }
};
#define N_MAGIC_TYPES (sizeof(magic_files) / sizeof(magic_files[0]))
wtap_open_return_val
mime_file_open(wtap *wth, int *err, gchar **err_info)
{
char magic_buf[128]; /* increase buffer size when needed */
int bytes_read;
gboolean found_file;
/* guint file_ok; */
guint i;
guint read_bytes = 12;
for (i = 0; i < N_MAGIC_TYPES; i++)
read_bytes = MAX(read_bytes, magic_files[i].magic_len);
read_bytes = (guint)MIN(read_bytes, sizeof(magic_buf));
bytes_read = file_read(magic_buf, read_bytes, wth->fh);
if (bytes_read < 0) {
*err = file_error(wth->fh, err_info);
return WTAP_OPEN_ERROR;
}
if (bytes_read == 0)
return WTAP_OPEN_NOT_MINE;
found_file = FALSE;
for (i = 0; i < N_MAGIC_TYPES; i++) {
if ((guint) bytes_read >= magic_files[i].magic_len && !memcmp(magic_buf, magic_files[i].magic, MIN(magic_files[i].magic_len, (guint) bytes_read))) {
if (!found_file) {
if (magic_files[i].magic == pcapng_premagic) {
if (memcmp(magic_buf + 8, pcapng_xmagic, sizeof(pcapng_xmagic)) &&
memcmp(magic_buf + 8, pcapng_swapped_xmagic, sizeof(pcapng_swapped_xmagic)))
continue;
}
found_file = TRUE;
} else
return WTAP_OPEN_NOT_MINE; /* many files matched, bad file */
}
}
if (!found_file)
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_MIME;
wth->file_encap = WTAP_ENCAP_MIME;
wth->file_tsprec = WTAP_TSPREC_SEC;
wth->subtype_read = wtap_full_file_read;
wth->subtype_seek_read = wtap_full_file_seek_read;
wth->snapshot_length = 0;
return WTAP_OPEN_MINE;
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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