Some network drivers call netif_stop_queue() when detecting loss of
carrier. This leads to packets being queued up at the qdisc level for
an unbound period of time. In order to prevent this effect, the core
networking stack will now cease to queue packets for any device, that
is operationally down (i.e. the queue is flushed and disabled).
Signed-off-by: Tommy S. Christensen <tommy.christensen@tpack.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
If we free up a partially processed packet because it's
skb->len dropped to zero, we need to decrement qlen because
we are dropping out of the top-level loop so it will do
the decrement for us.
Spotted by Herbert Xu.
Signed-off-by: David S. Miller <davem@davemloft.net>
The qlen should continue to decrement, even if we
pop partially processed SKBs back onto the receive queue.
Signed-off-by: David S. Miller <davem@davemloft.net>
Let's recap the problem. The current asynchronous netlink kernel
message processing is vulnerable to these attacks:
1) Hit and run: Attacker sends one or more messages and then exits
before they're processed. This may confuse/disable the next netlink
user that gets the netlink address of the attacker since it may
receive the responses to the attacker's messages.
Proposed solutions:
a) Synchronous processing.
b) Stream mode socket.
c) Restrict/prohibit binding.
2) Starvation: Because various netlink rcv functions were written
to not return until all messages have been processed on a socket,
it is possible for these functions to execute for an arbitrarily
long period of time. If this is successfully exploited it could
also be used to hold rtnl forever.
Proposed solutions:
a) Synchronous processing.
b) Stream mode socket.
Firstly let's cross off solution c). It only solves the first
problem and it has user-visible impacts. In particular, it'll
break user space applications that expect to bind or communicate
with specific netlink addresses (pid's).
So we're left with a choice of synchronous processing versus
SOCK_STREAM for netlink.
For the moment I'm sticking with the synchronous approach as
suggested by Alexey since it's simpler and I'd rather spend
my time working on other things.
However, it does have a number of deficiencies compared to the
stream mode solution:
1) User-space to user-space netlink communication is still vulnerable.
2) Inefficient use of resources. This is especially true for rtnetlink
since the lock is shared with other users such as networking drivers.
The latter could hold the rtnl while communicating with hardware which
causes the rtnetlink user to wait when it could be doing other things.
3) It is still possible to DoS all netlink users by flooding the kernel
netlink receive queue. The attacker simply fills the receive socket
with a single netlink message that fills up the entire queue. The
attacker then continues to call sendmsg with the same message in a loop.
Point 3) can be countered by retransmissions in user-space code, however
it is pretty messy.
In light of these problems (in particular, point 3), we should implement
stream mode netlink at some point. In the mean time, here is a patch
that implements synchronous processing.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Here is a little optimisation for the cb_lock used by netlink_dump.
While fixing that race earlier, I noticed that the reference count
held by cb_lock is completely useless. The reason is that in order
to obtain the protection of the reference count, you have to take
the cb_lock. But the only way to take the cb_lock is through
dereferencing the socket.
That is, you must already possess a reference count on the socket
before you can take advantage of the reference count held by cb_lock.
As a corollary, we can remve the reference count held by the cb_lock.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
htb_enqueue(): Free skb and return NET_XMIT_DROP if a packet is
destined for the direct_queue but the direct_queue is full. (Before
this: erroneously returned NET_XMIT_SUCCESS even though the packet was
not enqueued)
Signed-off-by: Asim Shankar <asimshankar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a trivial fix for a typo on Kconfig, where the Generic Random Early
Detection algorithm is abbreviated as RED instead of GRED.
Signed-off-by: Lucas Correia Villa Real <lucasvr@gobolinux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Converts remaining rtnetlink_link tables to use c99 designated
initializers to make greping a little bit easier.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Converts rtm_min and rtm_max arrays to use c99 designated
initializers for easier insertion of new message families.
RTM_GETMULTICAST and RTM_GETANYCAST did not have the minimal
message size specified which means that the netlink message
was parsed for routing attributes starting from the header.
Adds the proper minimal message sizes for these messages
(netlink header + common rtnetlink header) to fix this issue.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Converts xfrm_msg_min and xfrm_dispatch to use c99 designated
initializers to make greping a little bit easier. Also replaces
two hardcoded message type with meaningful names.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
I made a mistake in my last patch to the raw socket checksum code.
I used the value of inet->cork.length as the length of the payload.
While this works with normal packets, it breaks down when IPsec is
present since the cork length includes the extension header length.
So here is a patch to fix the length calculations.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some KernelDoc descriptions are updated to match the current code.
No code changes.
Signed-off-by: Martin Waitz <tali@admingilde.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I have recompiled Linux kernel 2.6.11.5 documentation for me and our
university students again. The documentation could be extended for more
sources which are equipped by structured comments for recent 2.6 kernels. I
have tried to proceed with that task. I have done that more times from 2.6.0
time and it gets boring to do same changes again and again. Linux kernel
compiles after changes for i386 and ARM targets. I have added references to
some more files into kernel-api book, I have added some section names as well.
So please, check that changes do not break something and that categories are
not too much skewed.
I have changed kernel-doc to accept "fastcall" and "asmlinkage" words reserved
by kernel convention. Most of the other changes are modifications in the
comments to make kernel-doc happy, accept some parameters description and do
not bail out on errors. Changed <pid> to @pid in the description, moved some
#ifdef before comments to correct function to comments bindings, etc.
You can see result of the modified documentation build at
http://cmp.felk.cvut.cz/~pisa/linux/lkdb-2.6.11.tar.gz
Some more sources are ready to be included into kernel-doc generated
documentation. Sources has been added into kernel-api for now. Some more
section names added and probably some more chaos introduced as result of quick
cleanup work.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Martin Waitz <tali@admingilde.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There were still a few comments left refering to verify_area, and two
functions, verify_area_skas & verify_area_tt that just wrap corresponding
access_ok_skas & access_ok_tt functions, just like verify_area does for
access_ok - deprecate those.
There was also a few places that still used verify_area in commented-out
code, fix those up to use access_ok.
After applying this one there should not be anything left but finally
removing verify_area completely, which will happen after a kernel release
or two.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes calls to synchronize_kernel(), deprecated in the earlier
"Deprecate synchronize_kernel, GPL replacement" patch to instead call the new
synchronize_rcu() and synchronize_sched() APIs.
Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
scumbags!
net/netlink/af_netlink.c: In function `netlink_sendmsg':
net/netlink/af_netlink.c:908: warning: implicit declaration of function `audit_get_loginuid'
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Most audit control messages are sent over netlink.In order to properly
log the identity of the sender of audit control messages, we would like
to add the loginuid to the netlink_creds structure, as per the attached
patch.
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
On Mon, Apr 25, 2005 at 12:01:13PM -0400, Dave Jones wrote:
> This has been brought up before.. http://lkml.org/lkml/2000/1/21/116
> but didnt seem to get resolved. This morning I got someone
> file a bugzilla about it breaking sysctl(8).
And here's its ipv6 counterpart.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tommy S. Christensen
David S. Miller
Herbert Xu
Asim Shankar
Folkert van Heusden
Lucas Correia Villa Real
Thomas Graf
Patrick McHardy
David Woodhouse
Martin Waitz
Pavel Pisa
Jesper Juhl
Paul E. McKenney
Andrew Morton
Serge Hallyn
Olaf Rempel
Dave Jones