[PATCH 1/5] Cryptomount support LUKS detached header

[John Lane <grub@jelmail.com>]

From: John Lane <john@lane.uk.net>

---
 grub-core/disk/cryptodisk.c | 22 ++++++++++++++++++----
 grub-core/disk/geli.c       |  7 +++++--
 grub-core/disk/luks.c       | 45 +++++++++++++++++++++++++++++++++++++--------
 include/grub/cryptodisk.h   |  5 +++--
 4 files changed, 63 insertions(+), 16 deletions(-)

diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index 82a3dcb..6f596a0 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -40,6 +40,7 @@ static const struct grub_arg_option options[] =
     /* TRANSLATORS: It's still restricted to cryptodisks only.  */
     {"all", 'a', 0, N_("Mount all."), 0, 0},
     {"boot", 'b', 0, N_("Mount all volumes with `boot' flag set."), 0, 0},
+    {"header", 'H', 0, N_("Read LUKS header from file"), 0, ARG_TYPE_STRING},
     {0, 0, 0, 0, 0, 0}
   };
 
@@ -803,6 +804,7 @@ grub_util_cryptodisk_get_uuid (grub_disk_t disk)
 
 static int check_boot, have_it;
 static char *search_uuid;
+static grub_file_t hdr;
 
 static void
 cryptodisk_close (grub_cryptodisk_t dev)
@@ -827,13 +829,13 @@ grub_cryptodisk_scan_device_real (const char *name, grub_disk_t source)
 
   FOR_CRYPTODISK_DEVS (cr)
   {
-    dev = cr->scan (source, search_uuid, check_boot);
+    dev = cr->scan (source, search_uuid, check_boot, hdr);
     if (grub_errno)
       return grub_errno;
     if (!dev)
       continue;
     
-    err = cr->recover_key (source, dev);
+    err = cr->recover_key (source, dev, hdr);
     if (err)
     {
       cryptodisk_close (dev);
@@ -874,7 +876,7 @@ grub_cryptodisk_cheat_mount (const char *sourcedev, const char *cheat)
 
   FOR_CRYPTODISK_DEVS (cr)
   {
-    dev = cr->scan (source, search_uuid, check_boot);
+    dev = cr->scan (source, search_uuid, check_boot,0);
     if (grub_errno)
       return grub_errno;
     if (!dev)
@@ -928,6 +930,18 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args)
   if (argc < 1 && !state[1].set && !state[2].set)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "device name required");
 
+  if (state[3].set) /* LUKS detached header */
+    {
+      if (state[0].set) /* Cannot use UUID lookup with detached header */
+        return GRUB_ERR_BAD_ARGUMENT;
+
+      hdr = grub_file_open (state[3].arg);
+      if (!hdr)
+        return grub_errno;
+    }
+  else
+    hdr = NULL;
+
   have_it = 0;
   if (state[0].set)
     {
@@ -1125,7 +1139,7 @@ GRUB_MOD_INIT (cryptodisk)
 {
   grub_disk_dev_register (&grub_cryptodisk_dev);
   cmd = grub_register_extcmd ("cryptomount", grub_cmd_cryptomount, 0,
-			      N_("SOURCE|-u UUID|-a|-b"),
+			      N_("SOURCE|-u UUID|-a|-b|-H file"),
 			      N_("Mount a crypto device."), options);
   grub_procfs_register ("luks_script", &luks_script);
 }
diff --git a/grub-core/disk/geli.c b/grub-core/disk/geli.c
index e9d2329..f4394eb 100644
--- a/grub-core/disk/geli.c
+++ b/grub-core/disk/geli.c
@@ -52,6 +52,7 @@
 #include <grub/dl.h>
 #include <grub/err.h>
 #include <grub/disk.h>
+#include <grub/file.h>
 #include <grub/crypto.h>
 #include <grub/partition.h>
 #include <grub/i18n.h>
@@ -243,7 +244,8 @@ grub_util_get_geli_uuid (const char *dev)
 
 static grub_cryptodisk_t
 configure_ciphers (grub_disk_t disk, const char *check_uuid,
-		   int boot_only)
+		   int boot_only,
+		   grub_file_t hdr __attribute__ ((unused)) )
 {
   grub_cryptodisk_t newdev;
   struct grub_geli_phdr header;
@@ -398,7 +400,8 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
 }
 
 static grub_err_t
-recover_key (grub_disk_t source, grub_cryptodisk_t dev)
+recover_key (grub_disk_t source, grub_cryptodisk_t dev,
+	     grub_file_t hdr __attribute__ ((unused)) )
 {
   grub_size_t keysize;
   grub_uint8_t digest[GRUB_CRYPTO_MAX_MDLEN];
diff --git a/grub-core/disk/luks.c b/grub-core/disk/luks.c
index 86c50c6..66e64c0 100644
--- a/grub-core/disk/luks.c
+++ b/grub-core/disk/luks.c
@@ -23,6 +23,7 @@
 #include <grub/dl.h>
 #include <grub/err.h>
 #include <grub/disk.h>
+#include <grub/file.h>
 #include <grub/crypto.h>
 #include <grub/partition.h>
 #include <grub/i18n.h>
@@ -66,7 +67,7 @@ gcry_err_code_t AF_merge (const gcry_md_spec_t * hash, grub_uint8_t * src,
 
 static grub_cryptodisk_t
 configure_ciphers (grub_disk_t disk, const char *check_uuid,
-		   int check_boot)
+		   int check_boot, grub_file_t hdr)
 {
   grub_cryptodisk_t newdev;
   const char *iptr;
@@ -86,11 +87,21 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
   int benbi_log = 0;
   grub_err_t err;
 
+  err = GRUB_ERR_NONE;
+
   if (check_boot)
     return NULL;
 
   /* Read the LUKS header.  */
-  err = grub_disk_read (disk, 0, 0, sizeof (header), &header);
+  if (hdr)
+  {
+    grub_file_seek (hdr, 0);
+    if (grub_file_read (hdr, &header, sizeof (header)) != sizeof (header))
+        err = GRUB_ERR_READ_ERROR;
+  }
+  else
+    err = grub_disk_read (disk, 0, 0, sizeof (header), &header);
+
   if (err)
     {
       if (err == GRUB_ERR_OUT_OF_RANGE)
@@ -304,12 +315,14 @@ configure_ciphers (grub_disk_t disk, const char *check_uuid,
   grub_memcpy (newdev->uuid, uuid, sizeof (newdev->uuid));
   newdev->modname = "luks";
   COMPILE_TIME_ASSERT (sizeof (newdev->uuid) >= sizeof (uuid));
+
   return newdev;
 }
 
 static grub_err_t
 luks_recover_key (grub_disk_t source,
-		  grub_cryptodisk_t dev)
+		  grub_cryptodisk_t dev,
+	          grub_file_t hdr)
 {
   struct grub_luks_phdr header;
   grub_size_t keysize;
@@ -321,8 +334,19 @@ luks_recover_key (grub_disk_t source,
   grub_err_t err;
   grub_size_t max_stripes = 1;
   char *tmp;
+  grub_uint32_t sector;
+
+  err = GRUB_ERR_NONE;
+
+  if (hdr)
+  {
+    grub_file_seek (hdr, 0);
+    if (grub_file_read (hdr, &header, sizeof (header)) != sizeof (header))
+        err = GRUB_ERR_READ_ERROR;
+  }
+  else
+    err = grub_disk_read (source, 0, 0, sizeof (header), &header);
 
-  err = grub_disk_read (source, 0, 0, sizeof (header), &header);
   if (err)
     return err;
 
@@ -391,13 +415,18 @@ luks_recover_key (grub_disk_t source,
 	  return grub_crypto_gcry_error (gcry_err);
 	}
 
+      sector = grub_be_to_cpu32 (header.keyblock[i].keyMaterialOffset);
       length = (keysize * grub_be_to_cpu32 (header.keyblock[i].stripes));
 
       /* Read and decrypt the key material from the disk.  */
-      err = grub_disk_read (source,
-			    grub_be_to_cpu32 (header.keyblock
-					      [i].keyMaterialOffset), 0,
-			    length, split_key);
+      if (hdr)
+        {
+	  grub_file_seek (hdr, sector * 512);
+          if (grub_file_read (hdr, split_key, length) != (grub_ssize_t)length)
+            err = GRUB_ERR_READ_ERROR;
+        }
+      else
+        err = grub_disk_read (source, sector, 0, length, split_key);
       if (err)
 	{
 	  grub_free (split_key);
diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h
index f2ad2a7..16dee3c 100644
--- a/include/grub/cryptodisk.h
+++ b/include/grub/cryptodisk.h
@@ -20,6 +20,7 @@
 #define GRUB_CRYPTODISK_HEADER	1
 
 #include <grub/disk.h>
+#include <grub/file.h>
 #include <grub/crypto.h>
 #include <grub/list.h>
 #ifdef GRUB_UTIL
@@ -106,8 +107,8 @@ struct grub_cryptodisk_dev
   struct grub_cryptodisk_dev **prev;
 
   grub_cryptodisk_t (*scan) (grub_disk_t disk, const char *check_uuid,
-			     int boot_only);
-  grub_err_t (*recover_key) (grub_disk_t disk, grub_cryptodisk_t dev);
+			     int boot_only, grub_file_t hdr);
+  grub_err_t (*recover_key) (grub_disk_t disk, grub_cryptodisk_t dev, grub_file_t hdr);
 };
 typedef struct grub_cryptodisk_dev *grub_cryptodisk_dev_t;
 
-- 
2.1.2