For TCP, verify that the sequence number in the ICMP packet falls within
the tcp receive window before performing any actions indicated by the
icmp packet.
Clean up some layering violations (access to tcp internals from in_pcb)
error will be passed up to the user, who will close the connection, so
it does not appear to make a sense to leave the connection open.
This also fixes a bug with kqueue, where the filter does not set EOF
on the connection, because the connection is still open.
Also remove calls to so{rw}wakeup, as we aren't doing anything with
them at the moment anyway.
Reviewed by: alfred, jesper
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
and 1.84 of src/sys/netinet/udp_usrreq.c
The changes broken down:
- remove 0 as a wildcard for addresses and port numbers in
src/sys/netinet/in_pcb.c:in_pcbnotify()
- add src/sys/netinet/in_pcb.c:in_pcbnotifyall() used to notify
all sessions with the specific remote address.
- change
- src/sys/netinet/udp_usrreq.c:udp_ctlinput()
- src/sys/netinet/tcp_subr.c:tcp_ctlinput()
to use in_pcbnotifyall() to notify multiple sessions, instead of
using in_pcbnotify() with 0 as src address and as port numbers.
- remove check for src port == 0 in
- src/sys/netinet/tcp_subr.c:tcp_ctlinput()
- src/sys/netinet/udp_usrreq.c:udp_ctlinput()
as they are no longer needed.
- move handling of redirects and host dead from in_pcbnotify() to
udp_ctlinput() and tcp_ctlinput(), so they will call
in_pcbnotifyall() to notify all sessions with the specific
remote address.
Approved by: jlemon
Inspired by: NetBSD
treat 0 as a wildcard in src/sys/in_pbc.c:in_pcbnotify()
It's sufficient to check for src|local port, as we'll have no
sessions with src|local port == 0
Without this a attacker sending ICMP messages, where the attached
IP header (+ 8 bytes) has the address and port numbers == 0, would
have the ICMP message applied to all sessions.
PR: kern/25195
Submitted by: originally by jesper, reimplimented by jlemon's advice
Reviewed by: jlemon
Approved by: jlemon
actually in the kernel. This structure is a different size than
what is currently in -CURRENT, but should hopefully be the last time
any application breakage is caused there. As soon as any major
inconveniences are removed, the definition of the in-kernel struct
ucred should be conditionalized upon defined(_KERNEL).
This also changes struct export_args to remove dependency on the
constantly-changing struct ucred, as well as limiting the bounds
of the size fields to the correct size. This means: a) mountd and
friends won't break all the time, b) mountd and friends won't crash
the kernel all the time if they don't know what they're doing wrt
actual struct export_args layout.
Reviewed by: bde
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>
messages send by routers when they deny our traffic, this causes
a timeout when trying to connect to TCP ports/services on a remote
host, which is blocked by routers or firewalls.
rfc1122 (Requirements for Internet Hosts) section 3.2.2.1 actually
requi re that we treat such a message for a TCP session, that we
treat it like if we had recieved a RST.
quote begin.
A Destination Unreachable message that is received MUST be
reported to the transport layer. The transport layer SHOULD
use the information appropriately; for example, see Sections
4.1.3.3, 4.2.3.9, and 4.2.4 below. A transport protocol
that has its own mechanism for notifying the sender that a
port is unreachable (e.g., TCP, which sends RST segments)
MUST nevertheless accept an ICMP Port Unreachable for the
same purpose.
quote end.
I've written a small extension that implement this, it also create
a sysctl "net.inet.tcp.icmp_admin_prohib_like_rst" to control if
this new behaviour is activated.
When it's activated (set to 1) we'll treat a ICMP administratively
prohibited message (icmp type 3 code 9, 10 and 13) for a TCP
sessions, as if we recived a TCP RST, but only if the TCP session
is in SYN_SENT state.
The reason for only reacting when in SYN_SENT state, is that this
will solve the problem, and at the same time minimize the risk of
this being abused.
I suggest that we enable this new behaviour by default, but it
would be a change of current behaviour, so if people prefer to
leave it disabled by default, at least for now, this would be ok
for me, the attached diff actually have the sysctl set to 0 by
default.
PR: 23086
Submitted by: Jesper Skriver <jesper@skriver.dk>
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.
Define __offsetof() in <machine/ansi.h>
Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>
Remove myriad of local offsetof() definitions.
Remove includes of <stddef.h> in kernel code.
NB: Kernelcode should *never* include from /usr/include !
Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.
Deprecate <struct.h> with a warning. The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.
Paritials reviews by: various.
Significant brucifications by: bde
delete the cloned route that is associated with the connection.
This does not exhaust the routing table memory when the system
is under a SYN flood attack. The route entry is not deleted if there
is any prior information cached in it.
Reviewed by: Peter Wemm,asmodai
Without this fix, all IPv6 TCP RST packet has wrong cksum value,
so IPv6 connect() trial to 5.0 machine won't fail until tcp connect timeout,
when they should fail soon.
Thanks to haro@tk.kubota.co.jp (Munehiro Matsuda) for his much debugging
help and detailed info.
for IPv4 communication.(IPv4 mapped IPv6 addr.)
Also removed IPv6 hoplimit initialization because it is alway done at
tcp_output.
Confirmed by: Bernd Walter <ticso@cicely5.cicely.de>
-opt_ipsec.h was missing on some tcp files (sorry for basic mistake)
-made buildable as above fix
-also added some missing IPv4 mapped IPv6 addr consideration into
ipsec4_getpolicybysock
This must be one of the reason why connections over IPsec hangs for
bigger packets.(which was reported on freebsd-current@freebsd.org)
But there still seems to be another bug and the problem is not yet fixed.
desperation measure in low-memory situations), walk the tcpbs and
flush the reassembly queues.
This behaviour is currently controlled by the debug.do_tcpdrain sysctl
(defaults to on).
Submitted by: Bosko Milekic <bmilekic@dsuper.net>
Reviewed by: wollman
packet divert at kernel for IPv6/IPv4 translater daemon
This includes queue related patch submitted by jburkhol@home.com.
Submitted by: queue related patch from jburkhol@home.com
Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project
for IPv6 yet)
With this patch, you can assigne IPv6 addr automatically, and can reply to
IPv6 ping.
Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project
Make a sonewconn3() which takes an extra argument (proc) so new sockets created
with sonewconn() from a user's system call get the correct credentials, not
just the parent's credentials.
- eliminate the fast/slow timeout lists for TCP and instead use a
callout entry for each timer.
- increase the TCP timer granularity to HZ
- implement "bad retransmit" recovery, as presented in
"On Estimating End-to-End Network Path Properties", by Allman and Paxson.
Submitted by: jlemon, wollmann
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
when a TCP "stealth" scan is directed at a *BSD box by ensuring the window
is 0 for all RST packets generated through tcp_respond()
Reviewed by: Don Lewis <Don.Lewis@tsc.tdk.com>
Obtained from: Bugtraq (from: Darren Reed <avalon@COOMBS.ANU.EDU.AU>)
4.1.4. Experimental Protocol
A system should not implement an experimental protocol unless it
is participating in the experiment and has coordinated its use of
the protocol with the developer of the protocol.
Pointed out by: Steinar Haug <sthaug@nethelp.no>
Define a parameter which indicates the maximum number of sockets in a
system, and use this to size the zone allocators used for sockets and
for certain PCBs.
Convert PF_LOCAL PCB structures to be type-stable and add a version number.
Define an external format for infomation about socket structures and use
it in several places.
Define a mechanism to get all PF_LOCAL and PF_INET PCB lists through
sysctl(3) without blocking network interrupts for an unreasonable
length of time. This probably still has some bugs and/or race
conditions, but it seems to work well enough on my machines.
It is now possible for `netstat' to get almost all of its information
via the sysctl(3) interface rather than reading kmem (changes to follow).
its own zone; this is used particularly by TCP which allocates both inpcb and
tcpcb in a single allocation. (Some hackery ensures that the tcpcb is
reasonably aligned.) Also keep track of the number of pcbs of each type
allocated, and keep a generation count (instance version number) for future
use.
a hashed port list. In the new scheme, in_pcblookup() goes away and is
replaced by a new routine, in_pcblookup_local() for doing the local port
check. Note that this implementation is space inefficient in that the PCB
struct is now too large to fit into 128 bytes. I might deal with this in the
future by using the new zone allocator, but I wanted these changes to be
extensively tested in their current form first.
Also:
1) Fixed off-by-one errors in the port lookup loops in in_pcbbind().
2) Got rid of some unneeded rehashing. Adding a new routine, in_pcbinshash()
to do the initialial hash insertion.
3) Renamed in_pcblookuphash() to in_pcblookup_hash() for easier readability.
4) Added a new routine, in_pcbremlists() to remove the PCB from the various
hash lists.
5) Added/deleted comments where appropriate.
6) Removed unnecessary splnet() locking. In general, the PCB functions should
be called at splnet()...there are unfortunately a few exceptions, however.
7) Reorganized a few structs for better cache line behavior.
8) Killed my TCP_ACK_HACK kludge. It may come back in a different form in
the future, however.
These changes have been tested on wcarchive for more than a month. In tests
done here, connection establishment overhead is reduced by more than 50
times, thus getting rid of one of the major networking scalability problems.
Still to do: make tcp_fastimo/tcp_slowtimo scale well for systems with a
large number of connections. tcp_fastimo is easy; tcp_slowtimo is difficult.
WARNING: Anything that knows about inpcb and tcpcb structs will have to be
recompiled; at the very least, this includes netstat(1).
where if you are using the "reset tcp" firewall command,
the kernel would write ethernet headers onto random kernel stack locations.
Fought to the death by: terry, julian, archie.
fix valid for 2.2 series as well.
cache lines. Removed the struct ip proto since only a couple of chars
were actually being used in it. Changed the order of compares in the
PCB hash lookup to take advantage of partial cache line fills (on PPro).
Discussed-with: wollman
the quality of the hash distribution. This does not fix a problem dealing
with poor distribution when using lots of IP aliases and listening
on the same port on every one of them...some other day perhaps; fixing
that requires significant code changes.
The use of xor was inspired by David S. Miller <davem@jenolan.rutgers.edu>
in the route. This allows us to remove the unconditional setting of the
pipesize in the route, which should mean that SO_SNDBUF and SO_RCVBUF
should actually work again. While we're at it:
- Convert udp_usrreq from `mondo switch statement from Hell' to new-style.
- Delete old TCP mondo switch statement from Hell, which had previously
been diked out.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
*' instead of caddr_t and it isn't optional (it never was). Most of the
netipx (and netns) pr_ctlinput functions abuse the second arg instead of
using the third arg but fixing this is beyond the scope of this round
of changes.
a few new wrinkles for MTU discovery which tcp_output() had better
be prepared to handle. ip_output() is also modified to do something
helpful in this case, since it has already calculated the information
we need.
turned out not to be necessary; simply watching for MTU decreases (which
we already did) automagically eliminates all the cases we were trying to
protect against.
middle of a fully-open window. Also, keep track of how many retransmits
we do as a result of MTU discovery. This may actually do more work than
necessary, but it's an unusual condition...
Suggested by: Janey Hoe <janey@lcs.mit.edu>
and gated on `options MTUDISC' in the source. It is also practically
untested becausse (sniff!) I don't have easy access to a network with
an MTU of less than an Ethernet. If you have a small MTU network,
please try it and tell me if it works!
know better when to cache values in the route, rather than relying on a
heuristic involving sequence numbers that broke when tcp_sendspace
was increased to 16k.
its connection parameters, we want to keep statistics on how often this
actually happens to see whether there is any work that needs to be done in
TCP itself.
Suggested by: John Wroclawski <jtw@lcs.mit.edu>
Bob Braden <braden@isi.edu>.
NB: This has not had David's TCP ACK hack re-integrated. It is not clear
what the correct solution to this problem is, if any. If a better solution
doesn't pop up in response to this message, I'll put David's code back in
(or he's welcome to do so himself).
