[OpenAFS-devel] ptuser interfaces: inconsistent downcasing

[Garrett Wollman]

<<On Wed, 25 Jul 2012 12:35:47 -0400, Jeffrey Altman <jaltman@secure-endpoints.com> said:

[I wrote:]
>> Another strange inconsistency: these routines are very unclear about
>> whether they are dealing with strings or not.  In places they are
>> careful to use interfaces like strncpy() that work on buffers, but
>> in other places they call string-only interfaces like stolower() that
>> will cheerfully walk off the end of the buffer.  Is PR_MAXNAMELEN
>> supposed to account for a trailing null or not?  (The RPC side of
>> things appears to believe the latter, although I haven't looked
>> closely enough to be certain.)

> While the server does append a NUL at the end of the string,
> any network facing code should not assume that a string is NUL
> terminated.  An evil server can choose to do otherwise.

What the server does in this case does not matter, because XDR always
uses counted strings and does not send the NUL over the wire.  Where
it does matter is what the client-side functions do with
maximum-length prnames.  I'm trying clarify exactly what the XDR code
will do in this case, and also what the correct behavior in the client
library should be when given an argument that exceeds PR_MAXNAMELEN-1
bytes: should it silently truncate or return an error?

-GAWollman