--- Klaus Weidner <[EMAIL PROTECTED]> wrote:
> I was a bit surprised that a "s2-s2" process can > connect successfully to > a "s3-s3" process, send it data, and select/poll(2) > waiting for data. > Select will tell it when the s3 process sent data, > and when it tries to > read that data read(2) will return 0 which the > program interprets as EOF. > I was expecting the connect to fail. This way it > permits "write up" > operations (which are compatible with LSPP but > frowned upon), and it > looks like a covert channel. TCP is a bidirectional protocol that requires communication in both directions. Evaluators have in the past "suggested" that the processes involved must be at the same MLS label (level and categories) for TCP connections to succeed. Write-up is OK for UDP, which provides no feedback. It is not OK for TCP, which does detectable handshaking. Casey Schaufler [EMAIL PROTECTED] -- redhat-lspp mailing list [email protected] https://www.redhat.com/mailman/listinfo/redhat-lspp
