Added a new '--pcap-file <file>' option to allow pcap files to
be processed directly by fwknopd instead of sniffing an interface. This
feature is mostly intended for debugging purposes.
This commit adds a new configuration variable "FORCE_NAT" to the access.conf
file:
For any valid SPA packet, force the requested connection to be NAT'd
through to the specified (usually internal) IP and port value. This is
useful if there are multiple internal systems running a service such as
SSHD, and you want to give transparent access to only one internal system
for each stanza in the access.conf file. This way, multiple external
users can each directly access only one internal system per SPA key.
This commit also implements a few minor code cleanups.
This commit does two major things:
1) Two new access.conf variables are added "ACCESS_EXPIRE" and
"ACCESS_EXPIRE_EPOCH" to allow access stanzas to be expired without having
to modify the access.conf file and restart fwknopd.
2) Allow an access stanza that matches the SPA source address to not
automatically short circuit other stanzas if there is an error (such as when
there are multiple encryption keys involved and an incoming SPA packet is
meant for, say, the second stanza and the first therefore doesn't allow
proper decryption).
This commit does several things. First, a memory leak in fwknopd has been
fixed by ensuring to free access.conf stanzas. This bug was found with the
new test suite running in --enable-valgrind mode. Here is what some of the
valgrind output looked like to find the leak:
==19217== 11 bytes in 1 blocks are indirectly lost in loss record 3 of 5
==19217== at 0x4C2815C: malloc (vg_replace_malloc.c:236)
==19217== by 0x52F6B81: strdup (strdup.c:43)
==19217== by 0x10FC8B: add_acc_string (access.c:49)
==19217== by 0x1105C8: parse_access_file (access.c:756)
==19217== by 0x10B79B: main (fwknopd.c:194)
==19217==
==19217== 16 bytes in 1 blocks are indirectly lost in loss record 4 of 5
==19217== at 0x4C27480: calloc (vg_replace_malloc.c:467)
==19217== by 0x10FEC0: add_source_mask (access.c:88)
==19217== by 0x110100: expand_acc_source (access.c:191)
==19217== by 0x1104B0: parse_access_file (access.c:500)
==19217== by 0x10B79B: main (fwknopd.c:194)
==19217==
==19217== 183 (152 direct, 31 indirect) bytes in 1 blocks are definitely lost in loss record 5 of 5
==19217== at 0x4C27480: calloc (vg_replace_malloc.c:467)
==19217== by 0x1103E4: parse_access_file (access.c:551)
==19217== by 0x10B79B: main (fwknopd.c:194)
==19217==
==19217== LEAK SUMMARY:
==19217== definitely lost: 152 bytes in 1 blocks
==19217== indirectly lost: 31 bytes in 3 blocks
==19217== possibly lost: 0 bytes in 0 blocks
==19217== still reachable: 8 bytes in 1 blocks
==19217== suppressed: 0 bytes in 0 blocks
Second, this commit changes how fwknopd acquires packet data with
pcap_dispatch() - packets are now processed within the callback function
process_packet() that is provided to pcap_dispatch(), the global packet
counter is incremented by the return value from pcap_dispatch() (since this is
the number of packets processed per pcap loop), and there are two new
fwknopd.conf variables PCAP_DISPATCH_COUNT and PCAP_LOOP_SLEEP to control the
number of packets that pcap_dispatch() should process per loop and the number
of microseconds that fwknopd should sleep per loop respectively. Without this
change, it was fairly easy to cause fwknopd to miss packets by creating bursts
of packets that would all be processed one at time with the usleep() delay
between each. For fwknopd deployed on a busy network and with a permissive
pcap filter (i.e. something other than the default that causes fwknopd to look
at, say, TCP ACK's), this change should help.
Third, the criteria that a packet must reach before data copying into the
buffer designed for SPA processing has been tightened. A packet less than
/greater than the minimum/maximum expected sizes is ignored before data is
copied, and the base64 check is done as well.
Added new command line options --fw-list-all and --fw-flush to allow all
firewall rules to be displayed including those not created by fwknopd, and
allow all firewall rules created by fwknopd to be deleted.
Also switched -D config dump output to stdout.
To override the value of the PCAP_FILTER variable in the fwknopd.conf
config file, a new fwknopd command line argument "--pcap-filter" was
added. This assists in various activities by making it trivial to
change how fwknopd acquires packet data without editing the fwknopd.conf
file. Here is an example:
fwknopd -i lo -f --pcap-filter "udp port 12345"
