On Sat, Dec 13, 2003 at 07:57:48AM +0000, Srinivas Vedula wrote: > > Hello, > > I am trying to write a transparent interface to some encrypted files so > that the user does not notice that the files are stored encrypted. All the > files are encrypted using the same key and algorithm. some time ago, I've worked for this problem, my interest was to made a framework for keep file transparent encrypted and user accessibiliy discrimined by a password. my solution was implemented on userspace http://www.s0ftpj.org/tools/umpf.tar.gz but have a lots of design problem and security tactics. (btw, my first focus on developing umpf was to made software very small and lightweight, file system indepentend and usable from a simple user, not requiring root) after, one friend have ported umpf on kernel module, "kumpf" http://kumpf.sf.net, this should better for some reason, this should interest you too, > As a quick hack I thought of catching the necessary system calls ( like > open, read, write) do the necessary encryption, decryption and return the > data to the user. This will work with write as the processing is done > before calling the system call. But with read the processing has to be done > after the system call completes. This can be may be done by changing the > way system calls are returned in entry.S. But I am not sure how to do this. umh, the way to change systemcall, runtime or not, is not a good way. for the future I'm thinking to implement a new kind of file supported, with some file operations act to dispense userspace program to manage the file function open/mmap/close/write etc... but is only a remote idea, because this software have sense (imho) only if used on multiuser system where you shouldn't work with root permission. on your systems... > Could some one suggest if this is a good way to proceed or if there is a > better solution to this. I do not want to use an encrypted filesystem > because the files are very few and part of different directories use symlink to encrypted loop-aes partition :) bye Claudio
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