linux-toradex.git/net/ipv4/tcp_ipv4.c, branch v3.0.77

tcp: resets are misrouted

2012-10-28T17:02:13+00:00

[ Upstream commit 4c67525849e0b7f4bd4fab2487ec9e43ea52ef29 ]

After commit e2446eaa ("tcp_v4_send_reset: binding oif to iif in no
sock case").. tcp resets are always lost, when routing is asymmetric.
Yes, backing out that patch will result in misrouting of resets for
dead connections which used interface binding when were alive, but we
actually cannot do anything here.  What's died that's died and correct
handling normal unbound connections is obviously a priority.

Comment to comment:
> This has few benefits:
>   1. tcp_v6_send_reset already did that.

It was done to route resets for IPv6 link local addresses. It was a
mistake to do so for global addresses. The patch fixes this as well.

Actually, the problem appears to be even more serious than guaranteed
loss of resets.  As reported by Sergey Soloviev , those
misrouted resets create a lot of arp traffic and huge amount of
unresolved arp entires putting down to knees NAT firewalls which use
asymmetric routing.

Signed-off-by: Alexey Kuznetsov 
Signed-off-by: Greg Kroah-Hartman

tcp: fix syncookie regression

2012-03-23T18:20:51+00:00

[ Upstream commit dfd25ffffc132c00070eed64200e8950da5d7e9d ]

commit ea4fc0d619 (ipv4: Don't use rt->rt_{src,dst} in ip_queue_xmit())
added a serious regression on synflood handling.

Simon Kirby discovered a successful connection was delayed by 20 seconds
before being responsive.

In my tests, I discovered that xmit frames were lost, and needed ~4
retransmits and a socket dst rebuild before being really sent.

In case of syncookie initiated connection, we use a different path to
initialize the socket dst, and inet->cork.fl.u.ip4 is left cleared.

As ip_queue_xmit() now depends on inet flow being setup, fix this by
copying the temp flowi4 we use in cookie_v4_check().

Reported-by: Simon Kirby 
Bisected-by: Simon Kirby 
Signed-off-by: Eric Dumazet 
Tested-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp_v4_send_reset: binding oif to iif in no sock case

2012-03-01T00:34:15+00:00

[ Upstream commit e2446eaab5585555a38ea0df4e01ff313dbb4ac9 ]

Binding RST packet outgoing interface to incoming interface
for tcp v4 when there is no socket associate with it.
when sk is not NULL, using sk->sk_bound_dev_if instead.
(suggested by Eric Dumazet).

This has few benefits:
1. tcp_v6_send_reset already did that.
2. This helps tcp connect with SO_BINDTODEVICE set. When
connection is lost, we still able to sending out RST using
same interface.
3. we are sending reply, it is most likely to be succeed
if iif is used

Signed-off-by: Shawn Lu 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: md5: using remote adress for md5 lookup in rst packet

2012-02-03T17:19:04+00:00

[ Upstream commit 8a622e71f58ec9f092fc99eacae0e6cf14f6e742 ]

md5 key is added in socket through remote address.
remote address should be used in finding md5 key when
sending out reset packet.

Signed-off-by: shawnlu 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: properly handle md5sig_pool references

2011-11-11T17:36:27+00:00

[ Upstream commit 260fcbeb1ae9e768a44c9925338fbacb0d7e5ba9 ]

tcp_v4_clear_md5_list() assumes that multiple tcp md5sig peers
only hold one reference to md5sig_pool. but tcp_v4_md5_do_add()
increases use count of md5sig_pool for each peer. This patch
makes tcp_v4_md5_do_add() only increases use count for the first
tcp md5sig peer.

Signed-off-by: Zheng Yan 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: Compute protocol sequence numbers and fragment IDs using MD5.

2011-08-16T01:31:35+00:00

Computers have become a lot faster since we compromised on the
partial MD4 hash which we use currently for performance reasons.

MD5 is a much safer choice, and is inline with both RFC1948 and
other ISS generators (OpenBSD, Solaris, etc.)

Furthermore, only having 24-bits of the sequence number be truly
unpredictable is a very serious limitation.  So the periodic
regeneration and 8-bit counter have been removed.  We compute and
use a full 32-bit sequence number.

For ipv6, DCCP was found to use a 32-bit truncated initial sequence
number (it needs 43-bits) and that is fixed here as well.

Reported-by: Dan Kaminsky 
Tested-by: Willy Tarreau 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: rfs: enable RFS before first data packet is received

2011-06-17T19:27:31+00:00

Le jeudi 16 juin 2011 à 23:38 -0400, David Miller a écrit :
> From: Ben Hutchings 
> Date: Fri, 17 Jun 2011 00:50:46 +0100
>
> > On Wed, 2011-06-15 at 04:15 +0200, Eric Dumazet wrote:
> >> @@ -1594,6 +1594,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
> >>  			goto discard;
> >>
> >>  		if (nsk != sk) {
> >> +			sock_rps_save_rxhash(nsk, skb->rxhash);
> >>  			if (tcp_child_process(sk, nsk, skb)) {
> >>  				rsk = nsk;
> >>  				goto reset;
> >>
> >
> > I haven't tried this, but it looks reasonable to me.
> >
> > What about IPv6?  The logic in tcp_v6_do_rcv() looks very similar.
>
> Indeed ipv6 side needs the same fix.
>
> Eric please add that part and resubmit.  And in fact I might stick
> this into net-2.6 instead of net-next-2.6
>

OK, here is the net-2.6 based one then, thanks !

[PATCH v2] net: rfs: enable RFS before first data packet is received

First packet received on a passive tcp flow is not correctly RFS
steered.

One sock_rps_record_flow() call is missing in inet_accept()

But before that, we also must record rxhash when child socket is setup.

Signed-off-by: Eric Dumazet 
CC: Tom Herbert 
CC: Ben Hutchings 
CC: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net: convert %p usage to %pK

2011-05-24T05:13:12+00:00

The %pK format specifier is designed to hide exposed kernel pointers,
specifically via /proc interfaces.  Exposing these pointers provides an
easy target for kernel write vulnerabilities, since they reveal the
locations of writable structures containing easily triggerable function
pointers.  The behavior of %pK depends on the kptr_restrict sysctl.

If kptr_restrict is set to 0, no deviation from the standard %p behavior
occurs.  If kptr_restrict is set to 1, the default, if the current user
(intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG
(currently in the LSM tree), kernel pointers using %pK are printed as 0's.
 If kptr_restrict is set to 2, kernel pointers using %pK are printed as
0's regardless of privileges.  Replacing with 0's was chosen over the
default "(null)", which cannot be parsed by userland %p, which expects
"(nil)".

The supporting code for kptr_restrict and %pK are currently in the -mm
tree.  This patch converts users of %p in net/ to %pK.  Cases of printing
pointers to the syslog are not covered, since this would eliminate useful
information for postmortem debugging and the reading of the syslog is
already optionally protected by the dmesg_restrict sysctl.

Signed-off-by: Dan Rosenberg 
Cc: James Morris 
Cc: Eric Dumazet 
Cc: Thomas Graf 
Cc: Eugene Teo 
Cc: Kees Cook 
Cc: Ingo Molnar 
Cc: David S. Miller 
Cc: Peter Zijlstra 
Cc: Eric Paris 
Signed-off-by: Andrew Morton 
Signed-off-by: David S. Miller

ipv4: Pass explicit destination address to rt_bind_peer().

2011-05-18T22:42:43+00:00

Signed-off-by: David S. Miller

ipv4: Pass explicit destination address to rt_get_peer().

2011-05-18T22:38:54+00:00

This will next trickle down to rt_bind_peer().

Signed-off-by: David S. Miller