Commit Graph

101 Commits

Author SHA1 Message Date
Andre Oppermann
4c037f8d6e Add another step of 1280 (gif(4) tunnels) to ip_next_mtu(). 2005-05-04 13:23:54 +00:00
Andre Oppermann
c773494edd Pass icmp_error() the MTU argument directly instead of
an interface pointer.  This simplifies a couple of uses
and removes some XXX workarounds.
2005-05-04 13:09:19 +00:00
Andre Oppermann
1aedbd9c80 Move Path MTU discovery ICMP processing from icmp_input() to
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
2005-04-21 14:29:34 +00:00
Warner Losh
c398230b64 /* -> /*- for license, minor formatting changes 2005-01-07 01:45:51 +00:00
Andre Oppermann
e098266191 Remove the last two global variables that are used to store packet state while
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.
2004-09-15 20:13:26 +00:00
Robert Watson
a4f757cd5d White space cleanup for netinet before branch:
- 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>
2004-08-16 18:32:07 +00:00
Max Laier
c550f2206d Define semantic of M_SKIP_FIREWALL more precisely, i.e. also pass associated
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
2004-07-17 05:10:06 +00:00
Stefan Farfeleder
439dfb0c35 Remove erroneous semicolons. 2004-07-13 16:06:19 +00:00
Hajimu UMEMOTO
cad1917d48 do not send icmp response if the original packet is encrypted.
Obtained from:	KAME
MFC after:	1 week
2004-06-07 09:56:59 +00:00
Maxim Konovalov
d0946241ac o IFNAMSIZ does include the trailing \0.
Approved by:	andre

o Document net.inet.icmp.reply_src.
2004-05-07 01:24:53 +00:00
Warner Losh
f36cfd49ad Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson
2004-04-07 20:46:16 +00:00
Max Laier
cc5934f5af Tweak existing header and other build infrastructure to be able to build
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)
2004-02-26 03:53:54 +00:00
Andre Oppermann
b74d89bbbb Add sysctl net.inet.icmp.reply_src to specify the interface name
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
2004-02-02 22:53:16 +00:00
Andre Oppermann
1488eac8ec More verbose description of the source ip address selection for ICMP replies.
Reviewed by:	bms
2004-02-02 22:17:09 +00:00
Andre Oppermann
53369ac9bb Limiters and sanity checks for TCP MSS (maximum segement size)
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
2004-01-08 17:40:07 +00:00
Andre Oppermann
87c3bd2755 According to RFC1812 we have to ignore ICMP redirects when we
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)
2004-01-06 23:20:07 +00:00
Andre Oppermann
97d8d152c2 Introduce tcp_hostcache and remove the tcp specific metrics from
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)
2003-11-20 20:07:39 +00:00
Andre Oppermann
26d02ca7ba Remove RTF_PRCLONING from routing table and adjust users of it
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)
2003-11-20 19:47:31 +00:00
Andre Oppermann
02c1c7070e Remove the global one-level rtcache variable and associated
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)
2003-11-14 21:48:57 +00:00
Andre Oppermann
16d6c90f5d Move global variables for icmp_input() to its stack. With SMP or
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)
2003-11-13 00:32:13 +00:00
Sam Leffler
9c855a36c1 Introduce the notion of "persistent mbuf tags"; these are tags that stay
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
2003-10-29 05:40:07 +00:00
Sam Leffler
d1dd20be6e Locking for updates to routing table entries. Each rtentry gets a mutex
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)
2003-10-04 03:44:50 +00:00
Robert Watson
baee0c3e66 Introduce two new MAC Framework and MAC policy entry points:
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
2003-08-21 18:39:16 +00:00
Matthew N. Dodd
57842a38fd Add a sysctl node allowing the specification of an address mask to use
when replying to ICMP Address Mask Request packets.
2003-03-21 15:43:06 +00:00
Warner Losh
a163d034fa Back out M_* changes, per decision of the TRB.
Approved by: trb
2003-02-19 05:47:46 +00:00
Alfred Perlstein
44956c9863 Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.
2003-01-21 08:56:16 +00:00
Sam Leffler
069f35d328 correct style bogons 2002-12-30 18:45:31 +00:00
Sam Leffler
00f21882a0 replace the special-purpose rate-limiting code with the general facility
just added; this tries to maintain the same behaviour vis a vis printing
the rate-limiting messages but need tweaking
2002-12-21 00:08:20 +00:00
Poul-Henning Kamp
53be11f680 Fix two instances of variant struct definitions in sys/netinet:
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
2002-10-20 22:52:07 +00:00
Sam Leffler
b9234fafa0 Tie new "Fast IPsec" code into the build. This involves the usual
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
2002-10-16 02:25:05 +00:00
Sam Leffler
5d84645305 Replace aux mbufs with packet tags:
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
2002-10-16 01:54:46 +00:00
Robert Watson
0070e096d7 Introduce support for Mandatory Access Control and extensible
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
2002-08-01 03:53:04 +00:00
Ruslan Ermilov
e3f406b3c1 Prevent icmp_reflect() from calling ip_output() with a NULL route
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
2002-03-22 16:45:54 +00:00
Alfred Perlstein
4d77a549fe Remove __P. 2002-03-19 21:25:46 +00:00
Mike Barcroft
fd8e4ebc8c o Move NTOHL() and associated macros into <sys/param.h>. These are
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
2002-02-18 20:35:27 +00:00
Ruslan Ermilov
84caf00847 Fix a panic condition in icmp_reflect() introduced in rev. 1.61.
(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>
2002-01-11 12:13:57 +00:00
Jonathan Lemon
effa274e9e whitespace fixes. 2001-12-14 19:32:47 +00:00
Ruslan Ermilov
bd7142087b - Make ip_rtaddr() global, and use it to look up the correct source
address in icmp_reflect().
- Two new "struct icmpstat" members: icps_badaddr and icps_noroute.

PR:		kern/31575
Obtained from:	BSD/OS
MFC after:	1 week
2001-11-30 10:40:28 +00:00
Dima Dorfman
0d4bef5dd4 In icmp_reflect(): If the packet was not addressed to us and was
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
2001-11-27 19:58:09 +00:00
Jonathan Lemon
807b8338ba Relocate the KASSERT for a null recvif to a location where it will
actually do some good.

Pointed out by: ru
2001-10-25 05:56:30 +00:00
Jonathan Lemon
ca925d9c17 Add a hash table that contains the list of internet addresses, and use
this in place of the in_ifaddr list when appropriate.  This improves
performance on hosts which have a large number of IP aliases.
2001-09-29 04:34:11 +00:00
Brooks Davis
9494d5968f Make faith loadable, unloadable, and clonable. 2001-09-25 18:40:52 +00:00
Julian Elischer
f0ffb944d2 Patches from Keiichi SHIMA <keiichi@iij.ad.jp>
to make ip use the standard protosw structure again.

Obtained from: Well, KAME I guess.
2001-09-03 20:03:55 +00:00
Ruslan Ermilov
c73d99b567 Add netstat(1) knob to reset net.inet.{ip|icmp|tcp|udp|igmp}.stats.
For example, ``netstat -s -p ip -z'' will show and reset IP stats.

PR:		bin/17338
2001-06-23 17:17:59 +00:00
Hajimu UMEMOTO
3384154590 Sync with recent KAME.
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
2001-06-11 12:39:29 +00:00
Jesper Skriver
b77d155dd3 MFC candidate.
Change code from PRC_UNREACH_ADMIN_PROHIB to PRC_UNREACH_PORT for
ICMP_UNREACH_PROTOCOL and ICMP_UNREACH_PORT

And let TCP treat PRC_UNREACH_PORT like PRC_UNREACH_ADMIN_PROHIB

This should fix the case where port unreachables for udp returned
ENETRESET instead of ECONNREFUSED

Problem found by:	Bill Fenner <fenner@research.att.com>
Reviewed by:		jlemon
2001-03-28 14:13:19 +00:00
Ruslan Ermilov
8ce3f3dd28 Make it possible to use IP_TTL and IP_TOS setsockopt(2) options
on certain types of SOCK_RAW sockets.  Also, use the ip.ttl MIB
variable instead of MAXTTL constant as the default time-to-live
value for outgoing IP packets all over the place, as we already
do this for TCP and UDP.

Reviewed by:	wollman
2001-03-09 12:22:51 +00:00
Ian Dowse
bfef7ed45c It was possible for ip_forward() to supply to icmp_error()
an IP header with ip_len in network byte order. For certain
values of ip_len, this could cause icmp_error() to write
beyond the end of an mbuf, causing mbuf free-list corruption.
This problem was observed during generation of ICMP redirects.

We now make quite sure that the copy of the IP header kept
for icmp_error() is stored in a non-shared mbuf header so
that it will not be modified by ip_output().

Also:
- Calculate the correct number of bytes that need to be
  retained for icmp_error(), instead of assuming that 64
  is enough (it's not).
- In icmp_error(), use m_copydata instead of bcopy() to
  copy from the supplied mbuf chain, in case the first 8
  bytes of IP payload are not stored directly after the IP
  header.
- Sanity-check ip_len in icmp_error(), and panic if it is
  less than sizeof(struct ip). Incoming packets with bad
  ip_len values are discarded in ip_input(), so this should
  only be triggered by bugs in the code, not by bad packets.

This patch results from code and suggestions from Ruslan, Bosko,
Jonathan Lemon and Matt Dillon, with important testing by Mike
Tancsa, who could reproduce this problem at will.

Reported by:	Mike Tancsa <mike@sentex.net>
Reviewed by:	ru, bmilekic, jlemon, dillon
2001-03-08 19:03:26 +00:00
Jonathan Lemon
e4bb5b0572 Allow ICMP unreachables which map into PRC_UNREACH_ADMIN_PROHIB to
reset TCP connections which are in the SYN_SENT state, if the sequence
number in the echoed ICMP reply is correct.  This behavior can be
controlled by the sysctl net.inet.tcp.icmp_may_rst.

Currently, only subtypes 2,3,10,11,12 are treated as such
(port, protocol and administrative unreachables).

Assocaiate an error code with these resets which is reported to the
user application: ENETRESET.

Disallow resetting TCP sessions which are not in a SYN_SENT state.

Reviewed by: jesper, -net
2001-02-23 20:51:46 +00:00
Poul-Henning Kamp
90fcbbd635 Remove unneeded loop increment in src/sys/netinet/in_pcb.c:in_pcbnotify
Add new PRC_UNREACH_ADMIN_PROHIB in sys/sys/protosw.h

Remove condition on TCP in src/sys/netinet/ip_icmp.c:icmp_input

In src/sys/netinet/ip_icmp.c:icmp_input set code = PRC_UNREACH_ADMIN_PROHIB
or PRC_UNREACH_HOST for all unreachables except ICMP_UNREACH_NEEDFRAG

Rename sysctl icmp_admin_prohib_like_rst to icmp_unreach_like_rst
to reflect the fact that we also react on ICMP unreachables that
are not administrative prohibited.  Also update the comments to
reflect this.

In sys/netinet/tcp_subr.c:tcp_ctlinput add code to treat
PRC_UNREACH_ADMIN_PROHIB and PRC_UNREACH_HOST different.

PR:		23986
Submitted by:	Jesper Skriver <jesper@skriver.dk>
2001-02-18 09:34:55 +00:00