kern/63961: ipfw2 uid matching doesn't work correctly

[Christian S.J. Peron]

Synopsis: ipfw2 uid matching doesn't work correctly

Responsible-Changed-From-To: ipfw->csjp
Responsible-Changed-By: csjp
Responsible-Changed-When: Tue Aug 24 20:57:29 GMT 2004
Responsible-Changed-Why: 
I think this might not be a bug.

If you want to match setup packets for TCP connections it
does work, but only if the connection has a PCB associated with it.
For instance, outgoing setup would have a PCB associated with it,
so ipfw could match on that:

dev0# ipfw show
00400     1      64 count tcp from any to any dst-port 4296 setup uid csjp

It should be noted that all the "setup" keyword does is set the
O_TCPFLAGS opcode and set the operand to TH_SYN for SYN packets.
I dont think Incoming TCP connection requests would not have a
PCB associated with it, so there is no-way that ipfw can look
up the credential associated with it.

However the UID negation problem looks like it could be a bug
either in how ipfw(8) reports the rule or how the kernel is
processing it. In either case I will look into it.

http://www.freebsd.org/cgi/query-pr.cgi?pr=63961