From 6cc27c29adf09106a53da97ea919aedb67af9b21 Mon Sep 17 00:00:00 2001
From: Maxim Fomin <maxim@fomin.one>
Date: Sat, 30 May 2020 11:21:44 +0100
Subject: [PATCH] Add 'bitlk' option to mount Bitlocker drives with cryptsetup.

---
 man/crypttab.xml            |  7 +++++++
 src/cryptsetup/cryptsetup.c | 20 +++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/man/crypttab.xml b/man/crypttab.xml
index 3170e5880f..2046911c78 100644
--- a/man/crypttab.xml
+++ b/man/crypttab.xml
@@ -177,6 +177,13 @@
         <option>size=</option>.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><option>bitlk</option></term>
+
+        <listitem><para>Decrypt Bitlocker drive. Encryption parameters
+        are deduced by cryptsetup from Bitlocker header.</para></listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><option>_netdev</option></term>
 
diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c
index 5886f86db6..c05e2d1351 100644
--- a/src/cryptsetup/cryptsetup.c
+++ b/src/cryptsetup/cryptsetup.c
@@ -38,7 +38,7 @@
 #define CRYPT_SECTOR_SIZE 512
 #define CRYPT_MAX_SECTOR_SIZE 4096
 
-static const char *arg_type = NULL; /* ANY_LUKS, CRYPT_LUKS1, CRYPT_LUKS2, CRYPT_TCRYPT or CRYPT_PLAIN */
+static const char *arg_type = NULL; /* ANY_LUKS, CRYPT_LUKS1, CRYPT_LUKS2, CRYPT_TCRYPT, CRYPT_BITLK or CRYPT_PLAIN */
 static char *arg_cipher = NULL;
 static unsigned arg_key_size = 0;
 static unsigned arg_sector_size = CRYPT_SECTOR_SIZE;
@@ -220,6 +220,11 @@ static int parse_one_option(const char *option) {
                 arg_submit_from_crypt_cpus = true;
         else if (streq(option, "luks"))
                 arg_type = ANY_LUKS;
+/* since cryptsetup 2.3.0 (Feb 2020) */
+#ifdef CRYPT_BITLK
+        else if (streq(option, "bitlk"))
+                arg_type = CRYPT_BITLK;
+#endif
         else if (streq(option, "tcrypt"))
                 arg_type = CRYPT_TCRYPT;
         else if (STR_IN_SET(option, "tcrypt-hidden", "tcrypthidden")) {
@@ -545,7 +550,7 @@ static int attach_tcrypt(
         return 0;
 }
 
-static int attach_luks_or_plain(
+static int attach_luks_or_plain_or_bitlk(
                 struct crypt_device *cd,
                 const char *name,
                 const char *key_file,
@@ -950,6 +955,15 @@ static int run(int argc, char *argv[]) {
                         }
                 }
 
+/* since cryptsetup 2.3.0 (Feb 2020) */
+#ifdef CRYPT_BITLK
+                if (!arg_type || STR_IN_SET(arg_type, ANY_LUKS, CRYPT_BITLK)) {
+                        r = crypt_load(cd, CRYPT_BITLK, NULL);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to load Bitlocker superblock on device %s: %m", crypt_get_device_name(cd));
+                }
+#endif
+
                 for (tries = 0; arg_tries == 0 || tries < arg_tries; tries++) {
                         _cleanup_strv_free_erase_ char **passwords = NULL;
 
@@ -988,7 +1002,7 @@ static int run(int argc, char *argv[]) {
                         if (streq_ptr(arg_type, CRYPT_TCRYPT))
                                 r = attach_tcrypt(cd, argv[2], key_file, key_data, key_data_size, passwords, flags);
                         else
-                                r = attach_luks_or_plain(cd, argv[2], key_file, key_data, key_data_size, passwords, flags, until);
+                                r = attach_luks_or_plain_or_bitlk(cd, argv[2], key_file, key_data, key_data_size, passwords, flags, until);
                         if (r >= 0)
                                 break;
                         if (r != -EAGAIN)