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5402baa5b5
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
107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2005 Stanislav Sedov
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <geom/geom.h>
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#include <geom/geom_dbg.h>
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#include <geom/label/g_label.h>
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#define EXT2FS_SB_OFFSET 1024
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#define EXT2_SUPER_MAGIC 0xef53
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#define EXT2_DYNAMIC_REV 1
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typedef struct e2sb {
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uint8_t fake1[56];
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uint16_t s_magic;
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uint8_t fake2[18];
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uint32_t s_rev_level;
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uint8_t fake3[40];
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char s_volume_name[16];
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} e2sb_t;
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static void
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g_label_ext2fs_taste(struct g_consumer *cp, char *label, size_t size)
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{
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struct g_provider *pp;
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e2sb_t *fs;
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char *s_volume_name;
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g_topology_assert_not();
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pp = cp->provider;
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label[0] = '\0';
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if ((EXT2FS_SB_OFFSET % pp->sectorsize) != 0)
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return;
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if (pp->sectorsize < sizeof(*fs))
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return;
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fs = g_read_data(cp, EXT2FS_SB_OFFSET, pp->sectorsize, NULL);
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if (fs == NULL)
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return;
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/* Check for magic and versio n*/
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if (fs->s_magic == EXT2_SUPER_MAGIC &&
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fs->s_rev_level == EXT2_DYNAMIC_REV) {
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G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
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pp->name);
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} else {
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goto exit_free;
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}
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s_volume_name = fs->s_volume_name;
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/* Terminate label */
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s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';
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if (s_volume_name[0] == '/')
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s_volume_name += 1;
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/* Check for volume label */
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if (s_volume_name[0] == '\0')
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goto exit_free;
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strlcpy(label, s_volume_name, size);
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exit_free:
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g_free(fs);
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}
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struct g_label_desc g_label_ext2fs = {
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.ld_taste = g_label_ext2fs_taste,
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.ld_dirprefix = "ext2fs/",
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.ld_enabled = 1
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};
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G_LABEL_INIT(ext2fs, g_label_ext2fs, "Create device nodes for EXT2FS volumes");
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