Fix ipfw packet matching errors with address tables.

Fix ipfw packet matching errors with address tables.

The ipfw tables lookup code caches the result of the last query.  The
kernel may process multiple packets concurrently, performing several
concurrent table lookups.  Due to an insufficient locking, a cached
result can become corrupted that could cause some addresses to be
incorrectly matched against a lookup table.

Submitted by:	ru
Reviewed by:	csjp, mlaier
Security:	CAN-2005-2019
Security:	FreeBSD-SA-05:13.ipfw

Correct bzip2 permission race condition vulnerability.

Obtained from:	Steve Grubb via RedHat
Security:	CAN-2005-0953
Security:	FreeBSD-SA-05:14.bzip2
Approved by:	obrien

Correct TCP connection stall denial of service vulnerability.

A TCP packets with the SYN flag set is accepted for established
connections, allowing an attacker to overwrite certain TCP options.

Submitted by:	Noritoshi Demizu
Reviewed by:	andre, Mohan Srinivasan
Security:	CAN-2005-2068
Security:	FreeBSD-SA-05:15.tcp

Approved by:	re (security blanket), cperciva