cluster if needed.
Fixes the TCP issues raised in I-D draft-gont-icmp-payload-00.txt.
This aids in-the-wild debugging a lot and allows the receiver to do
more elaborate checks on the validity of the response.
MFC after: 2 weeks
Sponsored by: TCP/IP Optimization Fundraise 2005
packet in an ICMP reply. The minimum of 8 bytes is internally
enforced. The maximum quotation is the remaining space in the
reply mbuf.
This option is added in response to the issues raised in I-D
draft-gont-icmp-payload-00.txt.
MFC after: 2 weeks
Spnsored by: TCP/IP Optimizations Fundraise 2005
the IP address the packet came through in. This is useful for routers
to show in traceroutes the actual path a packet has taken instead of
the possibly different return path.
The new sysctl is named net.inet.icmp.reply_from_interface and defaults
to off.
MFC after: 2 weeks
tcp_ctlinput() and subject it to active tcpcb and sequence
number checking. Previously any ICMP unreachable/needfrag
message would cause an update to the TCP hostcache. Now only
ICMP PMTU messages belonging to an active TCP session with
the correct src/dst/port and sequence number will update the
hostcache and complete the path MTU discovery process.
Note that we don't entirely implement the recommended counter
measures of Section 7.2 of the paper. However we close down
the possible degradation vector from trivially easy to really
complex and resource intensive. In addition we have limited
the smallest acceptable MTU with net.inet.tcp.minmss sysctl
for some time already, further reducing the effect of any
degradation due to an attack.
Security: draft-gont-tcpm-icmp-attacks-03.txt Section 7.2
MFC after: 3 days
it travels through the IP stack. This wasn't much of a problem because IP
source routing is disabled by default but when enabled together with SMP and
preemption it would have very likely cross-corrupted the IP options in transit.
The IP source route options of a packet are now stored in a mtag instead of the
global variable.
- Trailing tab/space cleanup
- Remove spurious spaces between or before tabs
This change avoids touching files that Andre likely has in his working
set for PFIL hooks changes for IPFW/DUMMYNET.
Approved by: re (scottl)
Submitted by: Xin LI <delphij@frontfree.net>
icmp_error() packets. While here retire PACKET_TAG_PF_GENERATED (which
served the same purpose) and use M_SKIP_FIREWALL in pf as well. This should
speed up things a bit as we get rid of the tag allocations.
Discussed with: juli
pf/pflog/pfsync as modules. Do not list them in NOTES or modules/Makefile
(i.e. do not connect it to any (automatic) builds - yet).
Approved by: bms(mentor)
used for the ICMP reply source in reponse to packets which are not
directly addressed to us. By default continue with with normal
source selection.
Reviewed by: bms
resource exhaustion attacks.
For network link optimization TCP can adjust its MSS and thus
packet size according to the observed path MTU. This is done
dynamically based on feedback from the remote host and network
components along the packet path. This information can be
abused to pretend an extremely low path MTU.
The resource exhaustion works in two ways:
o during tcp connection setup the advertized local MSS is
exchanged between the endpoints. The remote endpoint can
set this arbitrarily low (except for a minimum MTU of 64
octets enforced in the BSD code). When the local host is
sending data it is forced to send many small IP packets
instead of a large one.
For example instead of the normal TCP payload size of 1448
it forces TCP payload size of 12 (MTU 64) and thus we have
a 120 times increase in workload and packets. On fast links
this quickly saturates the local CPU and may also hit pps
processing limites of network components along the path.
This type of attack is particularly effective for servers
where the attacker can download large files (WWW and FTP).
We mitigate it by enforcing a minimum MTU settable by sysctl
net.inet.tcp.minmss defaulting to 256 octets.
o the local host is reveiving data on a TCP connection from
the remote host. The local host has no control over the
packet size the remote host is sending. The remote host
may chose to do what is described in the first attack and
send the data in packets with an TCP payload of at least
one byte. For each packet the tcp_input() function will
be entered, the packet is processed and a sowakeup() is
signalled to the connected process.
For example an attack with 2 Mbit/s gives 4716 packets per
second and the same amount of sowakeup()s to the process
(and context switches).
This type of attack is particularly effective for servers
where the attacker can upload large amounts of data.
Normally this is the case with WWW server where large POSTs
can be made.
We mitigate this by calculating the average MSS payload per
second. If it goes below 'net.inet.tcp.minmss' and the pps
rate is above 'net.inet.tcp.minmssoverload' defaulting to
1000 this particular TCP connection is resetted and dropped.
MITRE CVE: CAN-2004-0002
Reviewed by: sam (mentor)
MFC after: 1 day
are acting as router (ipforwarding enabled).
This doesn't fix the problem that host routes from ICMP redirects
are never removed from the kernel routing table but removes the
problem for machines doing packet forwarding.
Reviewed by: sam (mentor)
the routing table. Move all usage and references in the tcp stack
from the routing table metrics to the tcp hostcache.
It caches measured parameters of past tcp sessions to provide better
initial start values for following connections from or to the same
source or destination. Depending on the network parameters to/from
the remote host this can lead to significant speedups for new tcp
connections after the first one because they inherit and shortcut
the learning curve.
tcp_hostcache is designed for multiple concurrent access in SMP
environments with high contention and is hash indexed by remote
ip address.
It removes significant locking requirements from the tcp stack with
regard to the routing table.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
accordingly. The define is left intact for ABI compatibility
with userland.
This is a pre-step for the introduction of tcp_hostcache. The
network stack remains fully useable with this change.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
complex locking and rework ip_rtaddr() to do its own rtlookup.
Adopt all its callers to this and make ip_output() callable
with NULL rt pointer.
Reviewed by: sam (mentor)
preemption two CPUs can be in the same function at the same time
and clobber each others variables. Remove register declaration
from local variables.
Reviewed by: sam (mentor)
with an mbuf until it is reclaimed. This is in contrast to tags that
vanish when an mbuf chain passes through an interface. Persistent tags
are used, for example, by MAC labels.
Add an m_tag_delete_nonpersistent function to strip non-persistent tags
from mbufs and use it to strip such tags from packets as they pass through
the loopback interface and when turned around by icmp. This fixes problems
with "tag leakage".
Pointed out by: Jonathan Stone
Reviewed by: Robert Watson
that covers updates to the contents. Note this is separate from holding
a reference and/or locking the routing table itself.
Other/related changes:
o rtredirect loses the final parameter by which an rtentry reference
may be returned; this was never used and added unwarranted complexity
for locking.
o minor style cleanups to routing code (e.g. ansi-fy function decls)
o remove the logic to bump the refcnt on the parent of cloned routes,
we assume the parent will remain as long as the clone; doing this avoids
a circularity in locking during delete
o convert some timeouts to MPSAFE callouts
Notes:
1. rt_mtx in struct rtentry is guarded by #ifdef _KERNEL as user-level
applications cannot/do-no know about mutex's. Doing this requires
that the mutex be the last element in the structure. A better solution
is to introduce an externalized version of struct rtentry but this is
a major task because of the intertwining of rtentry and other data
structures that are visible to user applications.
2. There are known LOR's that are expected to go away with forthcoming
work to eliminate many held references. If not these will be resolved
prior to release.
3. ATM changes are untested.
Sponsored by: FreeBSD Foundation
Obtained from: BSD/OS (partly)
mac_reflect_mbuf_icmp()
mac_reflect_mbuf_tcp()
These entry points permit MAC policies to do "update in place"
changes to the labels on ICMP and TCP mbuf headers when an ICMP or
TCP response is generated to a packet outside of the context of
an existing socket. For example, in respond to a ping or a RST
packet to a SYN on a closed port.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
Remove the never completed _IP_VHL version, it has not caught on
anywhere and it would make us incompatible with other BSD netstacks
to retain this version.
Add a CTASSERT protecting sizeof(struct ip) == 20.
Don't let the size of struct ipq depend on the IPDIVERT option.
This is a functional no-op commit.
Approved by: re
configuration stuff as well as conditional code in the IPv4 and IPv6
areas. Everything is conditional on FAST_IPSEC which is mutually
exclusive with IPSEC (KAME IPsec implmentation).
As noted previously, don't use FAST_IPSEC with INET6 at the moment.
Reviewed by: KAME, rwatson
Approved by: silence
Supported by: Vernier Networks
o instead of a list of mbufs use a list of m_tag structures a la openbsd
o for netgraph et. al. extend the stock openbsd m_tag to include a 32-bit
ABI/module number cookie
o for openbsd compatibility define a well-known cookie MTAG_ABI_COMPAT and
use this in defining openbsd-compatible m_tag_find and m_tag_get routines
o rewrite KAME use of aux mbufs in terms of packet tags
o eliminate the most heavily used aux mbufs by adding an additional struct
inpcb parameter to ip_output and ip6_output to allow the IPsec code to
locate the security policy to apply to outbound packets
o bump __FreeBSD_version so code can be conditionalized
o fixup ipfilter's call to ip_output based on __FreeBSD_version
Reviewed by: julian, luigi (silent), -arch, -net, darren
Approved by: julian, silence from everyone else
Obtained from: openbsd (mostly)
MFC after: 1 month
kernel access control.
Add support for labeling most out-going ICMP messages using an
appropriate MAC entry point. Currently, we do not explicitly
label packet reflect (timestamp, echo request) ICMP events,
implicitly using the originating packet label since the mbuf is
reused. This will be made explicit at some point.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
pointer which will then result in the allocated route's reference
count never being decremented. Just flood ping the localhost and
watch refcnt of the 127.0.0.1 route with netstat(1).
Submitted by: jayanth
Back out ip_output.c,v 1.143 and ip_mroute.c,v 1.69 that allowed
ip_output() to be called with a NULL route pointer. The previous
paragraph shows why this was a bad idea in the first place.
MFC after: 0 days
deprecated in favor of the POSIX-defined lowercase variants.
o Change all occurrences of NTOHL() and associated marcros in the
source tree to use the lowercase function variants.
o Add missing license bits to sparc64's <machine/endian.h>.
Approved by: jake
o Clean up <machine/endian.h> files.
o Remove unused __uint16_swap_uint32() from i386's <machine/endian.h>.
o Remove prototypes for non-existent bswapXX() functions.
o Include <machine/endian.h> in <arpa/inet.h> to define the
POSIX-required ntohl() family of functions.
o Do similar things to expose the ntohl() family in libstand, <netinet/in.h>,
and <sys/param.h>.
o Prepend underscores to the ntohl() family to help deal with
complexities associated with having MD (asm and inline) versions, and
having to prevent exposure of these functions in other headers that
happen to make use of endian-specific defines.
o Create weak aliases to the canonical function name to help deal with
third-party software forgetting to include an appropriate header.
o Remove some now unneeded pollution from <sys/types.h>.
o Add missing <arpa/inet.h> includes in userland.
Tested on: alpha, i386
Reviewed by: bde, jake, tmm
(We should be able to handle locally originated IP packets, and
these do not have m_pkthdr.rcvif set.)
PR: kern/32806, kern/33766
Reviewed by: luigi
Fix tested by: Maxim Konovalov <maxim@macomnet.ru>,
Erwin Lansing <erwin@lansing.dk>
received on an interface without an IP address, try to find a
non-loopback AF_INET address to use. If that fails, drop it.
Previously, we used the address at the top of the in_ifaddrhead list,
which didn't make much sense, and would cause a panic if there were no
AF_INET addresses configured on the system.
PR: 29337, 30524
Reviewed by: ru, jlemon
Obtained from: NetBSD
This work was based on kame-20010528-freebsd43-snap.tgz and some
critical problem after the snap was out were fixed.
There are many many changes since last KAME merge.
TODO:
- The definitions of SADB_* in sys/net/pfkeyv2.h are still different
from RFC2407/IANA assignment because of binary compatibility
issue. It should be fixed under 5-CURRENT.
- ip6po_m member of struct ip6_pktopts is no longer used. But, it
is still there because of binary compatibility issue. It should
be removed under 5-CURRENT.
Reviewed by: itojun
Obtained from: KAME
MFC after: 3 weeks
