SCFS in Card
I was trying to put a configuration file (something like this)
in a smartcard to store
multiple keys in one smartcard for the Kerberos/smartcard project.
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#princ realm key_num PIN
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itoi CITI.UMICH.EDU 6
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itoi UMICH.EDU 7 1234
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honey CITIUMICH.EDU 8 1111
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I noticed that the lack of UNIX filesystem inside the card hurt. You
cannot read the entire file in one call because you do not know the
logical length of the config file. You have to read one byte by one
byte, making readBinary() call on every byte. (Is this right?) I
suppose it is going to be very slow.
To avoid it, we should take advantage of the .i file of scfs. I
suggest that we implement a set of functions to access smartcard files
in UNIX style, i.e., open, close, read, write, lseek, and fgets will
be really nice to parse config files.
And ... my dream is that every smartcard has .i file in its
directory, and .i is updated on every access (not just via scfs).
This way, we can use UNIX style files in smartcard from outside (via
scfs) and from inside (via the functions). I suggest to implement
the functions and write a document to convince smartcard vendors to
implement UNIX metadata like .i by default, or to let us implement it
for them.
How do you think?
12/14/1999 smartcards@umich.edu
