Security improvements:
- Increase the size of each syncookie secret from 32 to 128 bits
in order to make brute force attacks on the secrets much more
difficult.
- Always return the lowest order dword from the MD5 hash; this
allows us to expose 2 more bits of the cookie and makes ACK
floods which seek to guess the cookie value more difficult.
Performance improvements:
- Increase the lifetime of each syncookie from 4 seconds to 16
seconds. This increases the usefulness of syncookies during
an attack.
- From Yahoo!: Reduce the number of calls to MD5Update; this
results in a ~17% increase in cookie generation time here.
Reviewed by: hsu, jayanth, jlemon, nectar
MFC After: 15 seconds
packets coming out of a GIF tunnel are re-processed by ipfw, et. al.
By default they are not reprocessed. With the option they are.
This reverts 1.214. Prior to that change packets were not re-processed.
After they were which caused problems because packets do not have
distinguishing characteristics (like a special network if) that allows
them to be filtered specially.
This is really a stopgap measure designed for immediate MFC so that
4.8 has consistent handling to what was in 4.7.
PR: 48159
Reviewed by: Guido van Rooij <guido@gvr.org>
MFC after: 1 day
and enable it by default, with a limit of 16.
At the same time, tweak maxfragpackets downward so that in the worst
possible case, IP reassembly can use only 1/2 of all mbuf clusters.
MFC after: 3 days
Reviewed by: hsu
Liked by: bmah
OSes has probably caused more problems than it ever solved. Allow the
user to retire the old behavior by specifying their own privileged
range with,
net.inet.ip.portrange.reservedhigh default = IPPORT_RESERVED - 1
net.inet.ip.portrange.reservedlo default = 0
Now you can run that webserver without ever needing root at all. Or
just imagine, an ftpd that can really drop privileges, rather than
just set the euid, and still do PORT data transfers from 20/tcp.
Two edge cases to note,
# sysctl net.inet.ip.portrange.reservedhigh=0
Opens all ports to everyone, and,
# sysctl net.inet.ip.portrange.reservedhigh=65535
Locks all network activity to root only (which could actually have
been achieved before with ipfw(8), but is somewhat more
complicated).
For those who stick to the old religion that 0-1023 belong to root and
root alone, don't touch the knobs (or even lock them by raising
securelevel(8)), and nothing changes.
control block. Allow the socket and tcpcb structures to be freed
earlier than inpcb. Update code to understand an inp w/o a socket.
Reviewed by: hsu, silby, jayanth
Sponsored by: DARPA, NAI Labs
routine does not require a tcpcb to operate. Since we no longer keep
template mbufs around, move pseudo checksum out of this routine, and
merge it with the length update.
Sponsored by: DARPA, NAI Labs
- delay acks for T/TCP regardless of delack setting
- fix bug where a single pass through tcp_input might not delay acks
- use callout_active() instead of callout_pending()
Sponsored by: DARPA, NAI Labs
cr_uid.
Note: we do not have socheckuid() in RELENG_4, ip_fw2.c uses its
own macro for a similar purpose that is why ipfw2 in RELENG_4 processes
uid rules correctly. I will MFC the diff for code consistency.
Reported by: Oleg Baranov <ol@csa.ru>
Reviewed by: luigi
MFC after: 1 month
ipsec4_process_packet; they happen when a packet is dropped because
an SA acquire is initiated
Submitted by: Doug Ambrisko <ambrisko@verniernetworks.com>
you still don't want to use the two together, but it's ok to have
them in the same kernel (the problem that initiated this bandaid
has long since been fixed)
initialized until after a syncookie was generated. As a result,
all connections resulting from a returned cookie would end up using
a MSS of ~512 bytes. Now larger packets will be used where possible.
MFC after: 5 days
- Honor the previous behavior of maxfragpackets = 0 or -1
- Take a better stab at fragment statistics
- Move / correct a comment
Suggested by: maxim@
MFC after: 7 days
functions implemented approximately the same limits on fragment memory
usage, but in different fashions.)
End user visible changes:
- Fragment reassembly queues are freed in a FIFO manner when maxfragpackets
has been reached, rather than all reassembly stopping.
MFC after: 5 days
in addition to secure level 1. The mask supports up to a secure level of 8
but only add defines through CTLFLAG_SECURE3 for now.
As per the missif in the log entry for 1.11 of ip_fw2.c which added the
secure flag to the IPFW sysctl's in the first place, change the secure
level requirement from 1 to 3 now that we have support for it.
Reviewed by: imp
With Design Suggestions by: imp
were sometimes propagated using M_COPY_PKTHDR which actually did
something between a "move" and a "copy" operation. This is replaced
by M_MOVE_PKTHDR (which copies the pkthdr contents and "removes" it
from the source mbuf) and m_dup_pkthdr which copies the packet
header contents including any m_tag chain. This corrects numerous
problems whereby mbuf tags could be lost during packet manipulations.
These changes also introduce arguments to m_tag_copy and m_tag_copy_chain
to specify if the tag copy work should potentially block. This
introduces an incompatibility with openbsd which we may want to revisit.
Note that move/dup of packet headers does not handle target mbufs
that have a cluster bound to them. We may want to support this;
for now we watch for it with an assert.
Finally, M_COPYFLAGS was updated to include M_FIRSTFRAG|M_LASTFRAG.
Supported by: Vernier Networks
Reviewed by: Robert Watson <rwatson@FreeBSD.org>
Note that the original RFC 1323 (PAWS) says in 4.2.1 that the out of
order / reverse-time-indexed packet should be acknowledged as specified
in RFC-793 page 69 then dropped. The original PAWS code in FreeBSD (1994)
simply acknowledged the segment unconditionally, which is incorrect, and
was fixed in 1.183 (2002). At the moment we do not do checks for SYN or FIN
in addition to (tlen != 0), which may or may not be correct, but the
worst that ought to happen should be a retry by the sender.
in network byte order, but icmp_error() expects the IP header to
be in host order and the code here did not perform the necessary
swapping for the bridged case. This bug causes an "icmp_error: bad
length" panic when certain length IP packets (e.g. ip_len == 0x100)
are rejected by the firewall with an ICMP response.
MFC after: 3 days
