libblkid: add BitLocker detection
Supported: * WinVista version * Win7 and later versions (based on NTFS) * BitLockerToGo (for removable media; based on FAT32) Unfortunately, it's without LABEL and UUID. It seems BitLocker does not use volume_label and volume_serial stuff from NTFS header. Addresses: https://github.com/karelzak/util-linux/issues/617 Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak
parent
485241c0a3
commit
136f89ce5e
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@ -47,6 +47,7 @@ libblkid_la_SOURCES = \
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libblkid/src/superblocks/bcache.c \
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libblkid/src/superblocks/befs.c \
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libblkid/src/superblocks/bfs.c \
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libblkid/src/superblocks/bitlocker.c \
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libblkid/src/superblocks/btrfs.c \
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libblkid/src/superblocks/cramfs.c \
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libblkid/src/superblocks/ddf_raid.c \
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@ -0,0 +1,191 @@
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/*
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* Copyright (C) 2018 Karel Zak <kzak@redhat.com>
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*
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* This file may be redistributed under the terms of the
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* GNU Lesser General Public License.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <ctype.h>
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#include <stdint.h>
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#include "superblocks.h"
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#define BDE_HDR_SIZE 512
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#define BDE_HDR_OFFSET 0
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struct bde_header_win7 {
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/* 0 */ unsigned char boot_entry_point[3];
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/* 3 */ unsigned char fs_signature[8];
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/* 11 */ unsigned char __dummy1[67 - 11];
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/* 67 */ uint32_t volume_serial; /* NTFS uses 64bit serial number */
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/* 71 */ unsigned char volume_label[11]; /* "NO NAME\x20\x20\x20\x20" only */
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/* 82 */ unsigned char __dummy2[160 - 82];
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/* 160 */ unsigned char guid[16]; /* BitLocker specific GUID */
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/* 176 */ uint64_t fve_metadata_offset;
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} __attribute__((packed));
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struct bde_header_togo {
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/* 0 */ unsigned char boot_entry_point[3];
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/* 3 */ unsigned char fs_signature[8];
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/* 11 */ unsigned char __dummy[424 - 11];
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/* 424 */ unsigned char guid[16];
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/* 440 */ uint64_t fve_metadata_offset;
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} __attribute__((packed));
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struct bde_fve_metadata {
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/* 0 */ unsigned char signature[8];
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/* 8 */ uint16_t size;
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/* 10 */ uint16_t version;
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};
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enum {
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BDE_VERSION_VISTA = 0,
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BDE_VERSION_WIN7,
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BDE_VERSION_TOGO
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};
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#define BDE_MAGIC_VISTA "\xeb\x52\x90-FVE-FS-"
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#define BDE_MAGIC_WIN7 "\xeb\x58\x90-FVE-FS-"
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#define BDE_MAGIC_TOGO "\xeb\x58\x90MSWIN4.1"
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#define BDE_MAGIC_FVE "-FVE-FS-"
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static int get_bitlocker_type(const unsigned char *buf)
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{
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size_t i;
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static const char *map[] = {
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[BDE_VERSION_VISTA] = BDE_MAGIC_VISTA,
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[BDE_VERSION_WIN7] = BDE_MAGIC_WIN7,
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[BDE_VERSION_TOGO] = BDE_MAGIC_TOGO
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};
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for (i = 0; i < ARRAY_SIZE(map); i++) {
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if (memcmp(buf, map[i], 11) == 0)
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return (int) i;
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}
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return -1;
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}
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/* Returns: < 0 error, 1 nothing, 0 success
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*/
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static int get_bitlocker_headers(blkid_probe pr,
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int *type,
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const unsigned char **buf_hdr,
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const unsigned char **buf_fve)
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{
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const unsigned char *buf;
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struct bde_fve_metadata *fve;
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uint64_t off = 0;
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int kind;
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if (buf_hdr)
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*buf_hdr = NULL;
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if (buf_fve)
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*buf_fve = NULL;
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if (type)
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*type = -1;
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buf = blkid_probe_get_buffer(pr, BDE_HDR_OFFSET, BDE_HDR_SIZE);
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if (!buf)
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return errno ? -errno : 1;
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kind = get_bitlocker_type(buf);
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/* Check BitLocker header */
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switch (kind) {
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case BDE_VERSION_WIN7:
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off = le64_to_cpu(((struct bde_header_win7 *) buf)->fve_metadata_offset);
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break;
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case BDE_VERSION_TOGO:
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off = le64_to_cpu(((struct bde_header_togo *) buf)->fve_metadata_offset);
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break;
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case BDE_VERSION_VISTA:
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goto done;
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default:
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goto nothing;
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}
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if (!off)
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goto nothing;
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if (buf_hdr)
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*buf_hdr = buf;
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/* Check Bitlocker FVE metadata header */
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buf = blkid_probe_get_buffer(pr, off, sizeof(struct bde_fve_metadata));
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if (!buf)
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return errno ? -errno : 1;
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fve = (struct bde_fve_metadata *) buf;
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if (memcmp(fve->signature, BDE_MAGIC_FVE, sizeof(fve->signature)) != 0)
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goto nothing;
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if (buf_fve)
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*buf_fve = buf;
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done:
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if (type)
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*type = kind;
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return 0;
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nothing:
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return 1;
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}
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/*
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* This is used by vFAT and NTFS prober to avoid collisions with bitlocker.
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*/
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int blkid_probe_is_bitlocker(blkid_probe pr)
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{
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return get_bitlocker_headers(pr, NULL, NULL, NULL) == 0;
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}
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static int probe_bitlocker(blkid_probe pr,
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const struct blkid_idmag *mag __attribute__((__unused__)))
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{
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const unsigned char *buf_fve = NULL;
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const unsigned char *buf_hdr = NULL;
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int rc, kind;
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rc = get_bitlocker_headers(pr, &kind, &buf_hdr, &buf_fve);
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if (rc)
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return rc;
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if (kind == BDE_VERSION_WIN7) {
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struct bde_header_win7 *hdr = (struct bde_header_win7 *) buf_hdr;
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/* Unfortunately, it seems volume_serial is always zero */
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blkid_probe_sprintf_uuid(pr,
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(unsigned char *) &hdr->volume_serial,
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sizeof(hdr->volume_serial),
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"%016d", le32_to_cpu(hdr->volume_serial));
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}
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if (buf_fve) {
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struct bde_fve_metadata *fve = (struct bde_fve_metadata *) buf_fve;
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blkid_probe_sprintf_version(pr, "%d", fve->version);
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}
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return 0;
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}
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/* See header details:
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* https://github.com/libyal/libbde/blob/master/documentation/BitLocker%20Drive%20Encryption%20(BDE)%20format.asciidoc
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*/
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const struct blkid_idinfo bitlocker_idinfo =
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{
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.name = "BitLocker",
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.usage = BLKID_USAGE_CRYPTO,
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.probefunc = probe_bitlocker,
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.magics =
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{
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{ .magic = BDE_MAGIC_VISTA, .len = 11 },
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{ .magic = BDE_MAGIC_WIN7, .len = 11 },
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{ .magic = BDE_MAGIC_TOGO, .len = 11 },
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{ NULL }
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}
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};
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@ -115,6 +115,7 @@ static const struct blkid_idinfo *idinfos[] =
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&ubi_idinfo,
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&vdo_idinfo,
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&stratis_idinfo,
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&bitlocker_idinfo,
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/* Filesystems */
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&vfat_idinfo,
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@ -81,6 +81,7 @@ extern const struct blkid_idinfo bcache_idinfo;
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extern const struct blkid_idinfo mpool_idinfo;
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extern const struct blkid_idinfo vdo_idinfo;
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extern const struct blkid_idinfo stratis_idinfo;
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extern const struct blkid_idinfo bitlocker_idinfo;
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/*
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* superblock functions
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@ -105,4 +106,6 @@ extern int blkid_probe_set_id_label(blkid_probe pr, const char *name,
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extern int blkid_probe_set_utf8_id_label(blkid_probe pr, const char *name,
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unsigned char *data, size_t len, int enc);
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extern int blkid_probe_is_bitlocker(blkid_probe pr);
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#endif /* _BLKID_SUPERBLOCKS_H */
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@ -268,6 +268,9 @@ static int fat_valid_superblock(blkid_probe pr,
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}
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}
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if (blkid_probe_is_bitlocker(pr))
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return 0;
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return 1; /* valid */
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}
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