HardenedBSD/sys/geom/label/g_label_iso9660.c
Mark Johnston 5402baa5b5 g_label: Handle small sector sizes when tasting
Make sure that the provider sector size is large enough to contain a
valid label before trying to read it.  We performed this check already
for most label types, but not for several filesystem labels.

Reported by:	syzbot+f52918174cdf193ae29c@syzkaller.appspotmail.com
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
2021-09-07 11:19:29 -04:00

81 lines
2.6 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <geom/geom.h>
#include <geom/geom_dbg.h>
#include <geom/label/g_label.h>
#define ISO9660_MAGIC "\x01" "CD001" "\x01\x00"
#define ISO9660_OFFSET 0x8000
#define VOLUME_LEN 32
static void
g_label_iso9660_taste(struct g_consumer *cp, char *label, size_t size)
{
struct g_provider *pp;
char *sector, *volume;
g_topology_assert_not();
pp = cp->provider;
label[0] = '\0';
if ((ISO9660_OFFSET % pp->sectorsize) != 0)
return;
if (pp->sectorsize < 0x28 + VOLUME_LEN)
return;
sector = g_read_data(cp, ISO9660_OFFSET, pp->sectorsize, NULL);
if (sector == NULL)
return;
if (bcmp(sector, ISO9660_MAGIC, sizeof(ISO9660_MAGIC) - 1) != 0) {
g_free(sector);
return;
}
G_LABEL_DEBUG(1, "ISO9660 file system detected on %s.", pp->name);
volume = sector + 0x28;
bzero(label, size);
strlcpy(label, volume, MIN(size, VOLUME_LEN));
g_free(sector);
g_label_rtrim(label, size);
}
struct g_label_desc g_label_iso9660 = {
.ld_taste = g_label_iso9660_taste,
.ld_dirprefix = "iso9660/",
.ld_enabled = 1
};
G_LABEL_INIT(iso9660, g_label_iso9660, "Create device nodes for ISO9660 volume names");