cryptodisk: teach grub_cryptodisk_insert() about partitions (bug #45889)

[TJ]

https://savannah.gnu.org/bugs/index.php?45889

Boot disk with 3 LUKS/dm-crypt GPT partitions

(hd0,gpt3) (hd0,gpt4) (hd0,gpt5)

grub is in (hd0,gpt3). The others have a LVM VG each.

Using GRUB_ENABLE_CRYPTODISK=y I deliberately fail the first 
pass-phrase entry to get the rescue environment. I then

cryptomount hd0,gpt3

(crypto0) device is now present and prefix/root are set correctly. I 
insmod some other modules (exploring available functions) and

set debug=cryptodisk

I try to

cryptomount hd0,gpt4
cryptomount hd0,gpt4

and see the message

disk/cryptodisk.c:978: already mounted as crypto0

But ls shows only (crypto0)

With the attached patch the mounts now work:

Attempting to decrypt master key...
Enter passphrase for hd0,gpt3 ( ...UUID...)
Slot 0 opened
<<<< next line comes from temporary grub_dprintf() not included in 
patch >>>>
disk/cryptodisk.c:718: insert 0, source 'hd0,gpt3', id 128, dev_id 0
grub rescue> ls
(hd0) (hd0,gpt5) (hd0,gpt4) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (crypto0) 
(proc)
grub rescue> cryptomount hd0,gpt4
Attempting to decrypt master key...
Enter passphrase for hd0,gpt4 (...UUID...)
Slot 0 opened
disk/cryptodisk.c:718: insert 1, source 'hd0,gpt4', id 128, dev_id 0
grub rescue> cryptomount hd0,gpt5
Attempting to decrypt master key...
Enter passphrase for hd0,gpt5 (...UUID...)
Slot 0 opened
disk/cryptodisk.c:718: insert 2, source 'hd0,gpt4', id 128, dev_id 0
grub rescue> insmod lvm
grub rescue> ls
(lvm/VG_OS-x86_64.usr_local) (lvm/VG_OS-ubuntu_15.10_var) 
(lvm/VG_OS-ubuntu_15.10_rootfs) (lvm/VG_DATA-home) (hd0) (hd0,gpt5) 
(hd0,gpt4) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (crypto2) (crypto1) 
(crypto0) (proc)

---
 grub-core/disk/cryptodisk.c | 7 ++++++-
 include/grub/cryptodisk.h   | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index 82a3dcb..0e6bc3f 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -25,6 +25,7 @@
 #include <grub/fs.h>
 #include <grub/file.h>
 #include <grub/procfs.h>
+#include <grub/partition.h>

 #ifdef GRUB_UTIL
 #include <grub/emu/hostdisk.h>
@@ -718,6 +719,7 @@ grub_cryptodisk_insert (grub_cryptodisk_t newdev, 
const char *name,
   newdev->id = last_cryptodisk_id++;
   newdev->source_id = source->id;
   newdev->source_dev_id = source->dev->id;
+  newdev->partition_number = source->partition ? 
source->partition->number : 0;
   newdev->next = cryptodisk_list;
   cryptodisk_list = newdev;

@@ -740,7 +742,9 @@ grub_cryptodisk_get_by_source_disk (grub_disk_t 
disk)
   grub_cryptodisk_t dev;
   for (dev = cryptodisk_list; dev != NULL; dev = dev->next)
     if (dev->source_id == disk->id && dev->source_dev_id == 
disk->dev->id)
-      return dev;
+      if ((disk->partition && disk->partition->number == 
dev->partition_number) ||
+          (!disk->partition && dev->partition_number == 0))
+        return dev;
   return NULL;
 }

@@ -761,6 +765,7 @@ grub_cryptodisk_cheat_insert (grub_cryptodisk_t 
newdev, const char *name,
   newdev->cheat_fd = GRUB_UTIL_FD_INVALID;
   newdev->source_id = source->id;
   newdev->source_dev_id = source->dev->id;
+  newdev->partition_number = source->partition ? 
source->partition->number : 0;
   newdev->id = last_cryptodisk_id++;
   newdev->next = cryptodisk_list;
   cryptodisk_list = newdev;
diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h
index f2ad2a7..b638f2e 100644
--- a/include/grub/cryptodisk.h
+++ b/include/grub/cryptodisk.h
@@ -97,6 +97,7 @@ struct grub_cryptodisk
   grub_uint8_t rekey_key[64];
   grub_uint64_t last_rekey;
   int rekey_derived_size;
+  int partition_number;
 };
 typedef struct grub_cryptodisk *grub_cryptodisk_t;

--
2.5.0