[bug #33229] Truecrypt System Volume Header gets overwritten

[Patrick]

URL:
  <http://savannah.gnu.org/bugs/?33229>

                 Summary: Truecrypt System Volume Header gets overwritten
                 Project: GNU GRUB
            Submitted by: p55
            Submitted on: Wed 04 May 2011 04:13:34 PM GMT
                Category: Disk &amp; Partition
                Severity: Major
                Priority: 5 - Normal
              Item Group: Action Request
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: Patrick55
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 
                 Release: other
         Reproducibility: Every Time
         Planned Release: None

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Details:

Truecrypt System Volume Header gets overwritten when you install grub on the
master boot record of a hard disk with windows 7 installed and truecrypt full
_system_ disk encryption set up.

With system disk encryption the truecrypt volume header for the "system
partition" - i.e. the one that holds C:windows - is written to the last (512
byte-) sector (62) of the "dos compatibility area" after the master boot
record of the disk holding the "system partition". (The small 100mb partition
in front of the system partition that windows creates as it's boot partition
and where files like "bootmgr" reside is not encryptet, the system partition
is usually the second of the four partitions defined in the mbr)

Reference: http://www.truecrypt.org/docs/encryption-scheme
-> point 2., 2nd sentence

I believe this would not really be necessary. The core.img produces by
grub-mkimage is usually smaller than 61 sectors. It just gets bloated by the
grub_reed_solomon_add_redundancy() function in grub-setup.c

My idea is to modify the pc_partition_map_embed() function to not include
sector 62 of the disk - at least not if the offset of the first partition is
more than 63 sectors (2048 typically) anyway.

I will try to come up with some patch to implement this functionality.

Suggestions, warnings & wishes are welcome.






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