I have written kernel module, which enables map disk image as device...
i.e. I can do
dd if=/dev/hda5 of=imghda5
then I can map imghda5 as /dev/dg1 (for example) this device can be
mounted using usual mount utility. But for the sake of security module
checks pid of process, which try read/write something from /dev/dg1
if process with this pid is not a child of upper shell under which file was
mapped to /dev/dg1, then access denied... Theoretically, if root maps and
then mounts some image in one console, then root from another console
can't read this mount point... But naturally VFS saves readed directory
structure in memory, so if, for example, first root entered into directory
/aaa at this mount point, but not entered into directory /bbb, then second
root will see the root of this mount point, content of /aaa, but will not
see content of /bbb...
So, it's needed periodically clear cache buffers of VFS, which contain
inode information abount our mount point... What can you advice me???
Bye...
-----------------------------------------
Lyahovitsky Grigory (grigory@7ka.mipt.ru)
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