From ae7b79ff8a7fb576c018bc9a7eaf9e135b7b553e Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Tue, 24 Apr 2018 10:57:48 +0200
Subject: [PATCH 36/40] 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.
Upstream: http://github.com/karelzak/util-linux/commit/136f89ce5ed8cd159a1c56b5a775dada2363ecd3
Upstream: http://github.com/karelzak/util-linux/commit/47afae0caaa2b3440d6ac812079e3ada5f2aa0bd (bitlocker.c part)
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1812576
Addresses: https://github.com/karelzak/util-linux/issues/617
Signed-off-by: Karel Zak <kzak@redhat.com>
---
libblkid/src/Makemodule.am | 1 +
libblkid/src/superblocks/bitlocker.c | 191 +++++++++++++++++++++++++
libblkid/src/superblocks/superblocks.c | 1 +
libblkid/src/superblocks/superblocks.h | 3 +
libblkid/src/superblocks/vfat.c | 3 +
5 files changed, 199 insertions(+)
create mode 100644 libblkid/src/superblocks/bitlocker.c
diff --git a/libblkid/src/Makemodule.am b/libblkid/src/Makemodule.am
index 0e1c765fb..ea0230702 100644
--- a/libblkid/src/Makemodule.am
+++ b/libblkid/src/Makemodule.am
@@ -47,6 +47,7 @@ libblkid_la_SOURCES = \
libblkid/src/superblocks/bcache.c \
libblkid/src/superblocks/befs.c \
libblkid/src/superblocks/bfs.c \
+ libblkid/src/superblocks/bitlocker.c \
libblkid/src/superblocks/btrfs.c \
libblkid/src/superblocks/cramfs.c \
libblkid/src/superblocks/ddf_raid.c \
diff --git a/libblkid/src/superblocks/bitlocker.c b/libblkid/src/superblocks/bitlocker.c
new file mode 100644
index 000000000..111edf39b
--- /dev/null
+++ b/libblkid/src/superblocks/bitlocker.c
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2018 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <stdint.h>
+
+#include "superblocks.h"
+
+#define BDE_HDR_SIZE 512
+#define BDE_HDR_OFFSET 0
+
+struct bde_header_win7 {
+/* 0 */ unsigned char boot_entry_point[3];
+/* 3 */ unsigned char fs_signature[8];
+/* 11 */ unsigned char __dummy1[67 - 11];
+/* 67 */ uint32_t volume_serial; /* NTFS uses 64bit serial number */
+/* 71 */ unsigned char volume_label[11]; /* "NO NAME\x20\x20\x20\x20" only */
+/* 82 */ unsigned char __dummy2[160 - 82];
+/* 160 */ unsigned char guid[16]; /* BitLocker specific GUID */
+/* 176 */ uint64_t fve_metadata_offset;
+} __attribute__((packed));
+
+
+struct bde_header_togo {
+/* 0 */ unsigned char boot_entry_point[3];
+/* 3 */ unsigned char fs_signature[8];
+/* 11 */ unsigned char __dummy[424 - 11];
+/* 424 */ unsigned char guid[16];
+/* 440 */ uint64_t fve_metadata_offset;
+} __attribute__((packed));
+
+
+struct bde_fve_metadata {
+/* 0 */ unsigned char signature[8];
+/* 8 */ uint16_t size;
+/* 10 */ uint16_t version;
+};
+
+enum {
+ BDE_VERSION_VISTA = 0,
+ BDE_VERSION_WIN7,
+ BDE_VERSION_TOGO
+};
+
+#define BDE_MAGIC_VISTA "\xeb\x52\x90-FVE-FS-"
+#define BDE_MAGIC_WIN7 "\xeb\x58\x90-FVE-FS-"
+#define BDE_MAGIC_TOGO "\xeb\x58\x90MSWIN4.1"
+
+#define BDE_MAGIC_FVE "-FVE-FS-"
+
+static int get_bitlocker_type(const unsigned char *buf)
+{
+ size_t i;
+ static const char *map[] = {
+ [BDE_VERSION_VISTA] = BDE_MAGIC_VISTA,
+ [BDE_VERSION_WIN7] = BDE_MAGIC_WIN7,
+ [BDE_VERSION_TOGO] = BDE_MAGIC_TOGO
+ };
+
+ for (i = 0; i < ARRAY_SIZE(map); i++) {
+ if (memcmp(buf, map[i], 11) == 0)
+ return (int) i;
+ }
+
+ return -1;
+}
+
+/* Returns: < 0 error, 1 nothing, 0 success
+ */
+static int get_bitlocker_headers(blkid_probe pr,
+ int *type,
+ const unsigned char **buf_hdr,
+ const unsigned char **buf_fve)
+{
+
+ const unsigned char *buf;
+ const struct bde_fve_metadata *fve;
+ uint64_t off = 0;
+ int kind;
+
+ if (buf_hdr)
+ *buf_hdr = NULL;
+ if (buf_fve)
+ *buf_fve = NULL;
+ if (type)
+ *type = -1;
+
+ buf = blkid_probe_get_buffer(pr, BDE_HDR_OFFSET, BDE_HDR_SIZE);
+ if (!buf)
+ return errno ? -errno : 1;
+
+ kind = get_bitlocker_type(buf);
+
+ /* Check BitLocker header */
+ switch (kind) {
+ case BDE_VERSION_WIN7:
+ off = le64_to_cpu(((const struct bde_header_win7 *) buf)->fve_metadata_offset);
+ break;
+ case BDE_VERSION_TOGO:
+ off = le64_to_cpu(((const struct bde_header_togo *) buf)->fve_metadata_offset);
+ break;
+ case BDE_VERSION_VISTA:
+ goto done;
+ default:
+ goto nothing;
+ }
+
+ if (!off)
+ goto nothing;
+ if (buf_hdr)
+ *buf_hdr = buf;
+
+ /* Check Bitlocker FVE metadata header */
+ buf = blkid_probe_get_buffer(pr, off, sizeof(struct bde_fve_metadata));
+ if (!buf)
+ return errno ? -errno : 1;
+
+ fve = (const struct bde_fve_metadata *) buf;
+ if (memcmp(fve->signature, BDE_MAGIC_FVE, sizeof(fve->signature)) != 0)
+ goto nothing;
+ if (buf_fve)
+ *buf_fve = buf;
+done:
+ if (type)
+ *type = kind;
+ return 0;
+nothing:
+ return 1;
+}
+
+/*
+ * This is used by vFAT and NTFS prober to avoid collisions with bitlocker.
+ */
+int blkid_probe_is_bitlocker(blkid_probe pr)
+{
+ return get_bitlocker_headers(pr, NULL, NULL, NULL) == 0;
+}
+
+static int probe_bitlocker(blkid_probe pr,
+ const struct blkid_idmag *mag __attribute__((__unused__)))
+{
+ const unsigned char *buf_fve = NULL;
+ const unsigned char *buf_hdr = NULL;
+ int rc, kind;
+
+ rc = get_bitlocker_headers(pr, &kind, &buf_hdr, &buf_fve);
+ if (rc)
+ return rc;
+
+ if (kind == BDE_VERSION_WIN7) {
+ const struct bde_header_win7 *hdr = (const struct bde_header_win7 *) buf_hdr;
+
+ /* Unfortunately, it seems volume_serial is always zero */
+ blkid_probe_sprintf_uuid(pr,
+ (const unsigned char *) &hdr->volume_serial,
+ sizeof(hdr->volume_serial),
+ "%016d", le32_to_cpu(hdr->volume_serial));
+ }
+
+ if (buf_fve) {
+ const struct bde_fve_metadata *fve = (const struct bde_fve_metadata *) buf_fve;
+
+ blkid_probe_sprintf_version(pr, "%d", fve->version);
+ }
+ return 0;
+}
+
+/* See header details:
+ * https://github.com/libyal/libbde/blob/master/documentation/BitLocker%20Drive%20Encryption%20(BDE)%20format.asciidoc
+ */
+const struct blkid_idinfo bitlocker_idinfo =
+{
+ .name = "BitLocker",
+ .usage = BLKID_USAGE_CRYPTO,
+ .probefunc = probe_bitlocker,
+ .magics =
+ {
+ { .magic = BDE_MAGIC_VISTA, .len = 11 },
+ { .magic = BDE_MAGIC_WIN7, .len = 11 },
+ { .magic = BDE_MAGIC_TOGO, .len = 11 },
+ { NULL }
+ }
+};
diff --git a/libblkid/src/superblocks/superblocks.c b/libblkid/src/superblocks/superblocks.c
index 076541d1a..6dfd2be64 100644
--- a/libblkid/src/superblocks/superblocks.c
+++ b/libblkid/src/superblocks/superblocks.c
@@ -115,6 +115,7 @@ static const struct blkid_idinfo *idinfos[] =
&ubi_idinfo,
&vdo_idinfo,
&stratis_idinfo,
+ &bitlocker_idinfo,
/* Filesystems */
&vfat_idinfo,
diff --git a/libblkid/src/superblocks/superblocks.h b/libblkid/src/superblocks/superblocks.h
index 2723fb1d5..d677f85bc 100644
--- a/libblkid/src/superblocks/superblocks.h
+++ b/libblkid/src/superblocks/superblocks.h
@@ -81,6 +81,7 @@ extern const struct blkid_idinfo bcache_idinfo;
extern const struct blkid_idinfo mpool_idinfo;
extern const struct blkid_idinfo vdo_idinfo;
extern const struct blkid_idinfo stratis_idinfo;
+extern const struct blkid_idinfo bitlocker_idinfo;
/*
* superblock functions
@@ -105,4 +106,6 @@ extern int blkid_probe_set_id_label(blkid_probe pr, const char *name,
extern int blkid_probe_set_utf8_id_label(blkid_probe pr, const char *name,
unsigned char *data, size_t len, int enc);
+extern int blkid_probe_is_bitlocker(blkid_probe pr);
+
#endif /* _BLKID_SUPERBLOCKS_H */
diff --git a/libblkid/src/superblocks/vfat.c b/libblkid/src/superblocks/vfat.c
index 3aeba018a..29b3c501c 100644
--- a/libblkid/src/superblocks/vfat.c
+++ b/libblkid/src/superblocks/vfat.c
@@ -268,6 +268,9 @@ static int fat_valid_superblock(blkid_probe pr,
}
}
+ if (blkid_probe_is_bitlocker(pr))
+ return 0;
+
return 1; /* valid */
}
--
2.25.4