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  1. 25 10月, 2010 1 次提交
    • E
      netlink: fix netlink_change_ngroups() · 5c398dc8
      由 Eric Dumazet 提交于 
      commit 6c04bb18 (netlink: use call_rcu for netlink_change_ngroups)
used a somewhat convoluted and racy way to perform call_rcu().

The old block of memory is freed after a grace period, but the rcu_head
used to track it is located in new block.

This can clash if we call two times or more netlink_change_ngroups(),
and a block is freed before another. call_rcu() called on different cpus
makes no guarantee in order of callbacks.

Fix this using a more standard way of handling this : Each block of
memory contains its own rcu_head, so that no 'use after free' can
happens.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Johannes Berg <johannes@sipsolutions.net>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      5c398dc8
  3. 01 9月, 2010 1 次提交
  5. 19 8月, 2010 1 次提交
    • J
      netlink: fix compat recvmsg · 68d6ac6d
      由 Johannes Berg 提交于 
      Since
commit 1dacc76d
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Wed Jul 1 11:26:02 2009 +0000

    net/compat/wext: send different messages to compat tasks

we had a race condition when setting and then
restoring frag_list. Eric attempted to fix it,
but the fix created even worse problems.

However, the original motivation I had when I
added the code that turned out to be racy is
no longer clear to me, since we only copy up
to skb->len to userspace, which doesn't include
the frag_list length. As a result, not doing
any frag_list clearing and restoring avoids
the race condition, while not introducing any
other problems.

Additionally, while preparing this patch I found
that since none of the remaining netlink code is
really aware of the frag_list, we need to use the
original skb's information for packet information
and credentials. This fixes, for example, the
group information received by compat tasks.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: stable@kernel.org [2.6.31+, for 2.6.35 revert 1235f504]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      68d6ac6d
  7. 16 8月, 2010 1 次提交
  9. 27 7月, 2010 1 次提交
  11. 21 7月, 2010 1 次提交
    • N
      drop_monitor: convert some kfree_skb call sites to consume_skb · 70d4bf6d
      由 Neil Horman 提交于 
      Convert a few calls from kfree_skb to consume_skb

Noticed while I was working on dropwatch that I was detecting lots of internal
skb drops in several places.  While some are legitimate, several were not,
freeing skbs that were at the end of their life, rather than being discarded due
to an error.  This patch converts those calls sites from using kfree_skb to
consume_skb, which quiets the in-kernel drop_monitor code from detecting them as
drops.  Tested successfully by myself
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      70d4bf6d
  13. 17 6月, 2010 1 次提交
  15. 22 5月, 2010 1 次提交
  17. 02 4月, 2010 1 次提交
  19. 27 3月, 2010 1 次提交
  21. 21 3月, 2010 1 次提交
  23. 28 2月, 2010 1 次提交
  25. 04 2月, 2010 1 次提交
    • A
      netlink: fix for too early rmmod · 974c37e9
      由 Alexey Dobriyan 提交于 
      Netlink code does module autoload if protocol userspace is asking for is
not ready. However, module can dissapear right after it was autoloaded.
Example: modprobe/rmmod stress-testing and xfrm_user.ko providing NETLINK_XFRM.

netlink_create() in such situation _will_ create userspace socket and
_will_not_ pin module. Now if module was removed and we're going to call
->netlink_rcv into nothing:

BUG: unable to handle kernel paging request at ffffffffa02f842a
					       ^^^^^^^^^^^^^^^^
	modules are loaded near these addresses here

IP: [<ffffffffa02f842a>] 0xffffffffa02f842a
PGD 161f067 PUD 1623063 PMD baa12067 PTE 0
Oops: 0010 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/uevent
CPU 1
Pid: 11515, comm: ip Not tainted 2.6.33-rc5-netns-00594-gaaa5728-dirty #6 P5E/P5E
RIP: 0010:[<ffffffffa02f842a>]  [<ffffffffa02f842a>] 0xffffffffa02f842a
RSP: 0018:ffff8800baa3db48  EFLAGS: 00010292
RAX: ffff8800baa3dfd8 RBX: ffff8800be353640 RCX: 0000000000000000
RDX: ffffffff81959380 RSI: ffff8800bab7f130 RDI: 0000000000000001
RBP: ffff8800baa3db58 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000011
R13: ffff8800be353640 R14: ffff8800bcdec240 R15: ffff8800bd488010
FS:  00007f93749656f0(0000) GS:ffff880002300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffffffffa02f842a CR3: 00000000ba82b000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process ip (pid: 11515, threadinfo ffff8800baa3c000, task ffff8800bab7eb30)
Stack:
 ffffffff813637c0 ffff8800bd488000 ffff8800baa3dba8 ffffffff8136397d
<0> 0000000000000000 ffffffff81344adc 7fffffffffffffff 0000000000000000
<0> ffff8800baa3ded8 ffff8800be353640 ffff8800bcdec240 0000000000000000
Call Trace:
 [<ffffffff813637c0>] ? netlink_unicast+0x100/0x2d0
 [<ffffffff8136397d>] netlink_unicast+0x2bd/0x2d0

	netlink_unicast_kernel:
		nlk->netlink_rcv(skb);

 [<ffffffff81344adc>] ? memcpy_fromiovec+0x6c/0x90
 [<ffffffff81364263>] netlink_sendmsg+0x1d3/0x2d0
 [<ffffffff8133975b>] sock_sendmsg+0xbb/0xf0
 [<ffffffff8106cdeb>] ? __lock_acquire+0x27b/0xa60
 [<ffffffff810a18c3>] ? might_fault+0x73/0xd0
 [<ffffffff810a18c3>] ? might_fault+0x73/0xd0
 [<ffffffff8106db22>] ? __lock_release+0x82/0x170
 [<ffffffff810a190e>] ? might_fault+0xbe/0xd0
 [<ffffffff810a18c3>] ? might_fault+0x73/0xd0
 [<ffffffff81344c77>] ? verify_iovec+0x47/0xd0
 [<ffffffff8133a509>] sys_sendmsg+0x1a9/0x360
 [<ffffffff813c2be5>] ? _raw_spin_unlock_irqrestore+0x65/0x70
 [<ffffffff8106aced>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff813c2bc2>] ? _raw_spin_unlock_irqrestore+0x42/0x70
 [<ffffffff81197004>] ? __up_read+0x84/0xb0
 [<ffffffff8106ac95>] ? trace_hardirqs_on_caller+0x145/0x190
 [<ffffffff813c207f>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff8100262b>] system_call_fastpath+0x16/0x1b
Code:  Bad RIP value.
RIP  [<ffffffffa02f842a>] 0xffffffffa02f842a
 RSP <ffff8800baa3db48>
CR2: ffffffffa02f842a

If module was quickly removed after autoloading, return -E.

Return -EPROTONOSUPPORT if module was quickly removed after autoloading.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      974c37e9
  27. 26 11月, 2009 1 次提交
  29. 17 11月, 2009 1 次提交
  31. 11 11月, 2009 1 次提交
  33. 06 11月, 2009 1 次提交
  35. 07 10月, 2009 1 次提交
  37. 01 10月, 2009 1 次提交
  39. 27 9月, 2009 1 次提交
  41. 25 9月, 2009 1 次提交
    • J
      genetlink: fix netns vs. netlink table locking (2) · b8273570
      由 Johannes Berg 提交于 
      Similar to commit d136f1bd,
there's a bug when unregistering a generic netlink family,
which is caught by the might_sleep() added in that commit:

    BUG: sleeping function called from invalid context at net/netlink/af_netlink.c:183
    in_atomic(): 1, irqs_disabled(): 0, pid: 1510, name: rmmod
    2 locks held by rmmod/1510:
     #0:  (genl_mutex){+.+.+.}, at: [<ffffffff8138283b>] genl_unregister_family+0x2b/0x130
     #1:  (rcu_read_lock){.+.+..}, at: [<ffffffff8138270c>] __genl_unregister_mc_group+0x1c/0x120
    Pid: 1510, comm: rmmod Not tainted 2.6.31-wl #444
    Call Trace:
     [<ffffffff81044ff9>] __might_sleep+0x119/0x150
     [<ffffffff81380501>] netlink_table_grab+0x21/0x100
     [<ffffffff813813a3>] netlink_clear_multicast_users+0x23/0x60
     [<ffffffff81382761>] __genl_unregister_mc_group+0x71/0x120
     [<ffffffff81382866>] genl_unregister_family+0x56/0x130
     [<ffffffffa0007d85>] nl80211_exit+0x15/0x20 [cfg80211]
     [<ffffffffa000005a>] cfg80211_exit+0x1a/0x40 [cfg80211]

Fix in the same way by grabbing the netlink table lock
before doing rcu_read_lock().
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b8273570
  43. 22 9月, 2009 1 次提交
  45. 15 9月, 2009 1 次提交
    • J
      genetlink: fix netns vs. netlink table locking · d136f1bd
      由 Johannes Berg 提交于 
      Since my commits introducing netns awareness into
genetlink we can get this problem:

BUG: scheduling while atomic: modprobe/1178/0x00000002
2 locks held by modprobe/1178:
 #0:  (genl_mutex){+.+.+.}, at: [<ffffffff8135ee1a>] genl_register_mc_grou
 #1:  (rcu_read_lock){.+.+..}, at: [<ffffffff8135eeb5>] genl_register_mc_g
Pid: 1178, comm: modprobe Not tainted 2.6.31-rc8-wl-34789-g95cb731-dirty #
Call Trace:
 [<ffffffff8103e285>] __schedule_bug+0x85/0x90
 [<ffffffff81403138>] schedule+0x108/0x588
 [<ffffffff8135b131>] netlink_table_grab+0xa1/0xf0
 [<ffffffff8135c3a7>] netlink_change_ngroups+0x47/0x100
 [<ffffffff8135ef0f>] genl_register_mc_group+0x12f/0x290

because I overlooked that netlink_table_grab() will
schedule, thinking it was just the rwlock. However,
in the contention case, that isn't actually true.

Fix this by letting the code grab the netlink table
lock first and then the RCU for netns protection.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d136f1bd
  47. 25 8月, 2009 1 次提交
  49. 15 7月, 2009 1 次提交
    • J
      net/compat/wext: send different messages to compat tasks · 1dacc76d
      由 Johannes Berg 提交于 
      Wireless extensions have the unfortunate problem that events
are multicast netlink messages, and are not independent of
pointer size. Thus, currently 32-bit tasks on 64-bit platforms
cannot properly receive events and fail with all kinds of
strange problems, for instance wpa_supplicant never notices
disassociations, due to the way the 64-bit event looks (to a
32-bit process), the fact that the address is all zeroes is
lost, it thinks instead it is 00:00:00:00:01:00.

The same problem existed with the ioctls, until David Miller
fixed those some time ago in an heroic effort.

A different problem caused by this is that we cannot send the
ASSOCREQIE/ASSOCRESPIE events because sending them causes a
32-bit wpa_supplicant on a 64-bit system to overwrite its
internal information, which is worse than it not getting the
information at all -- so we currently resort to sending a
custom string event that it then parses. This, however, has a
severe size limitation we are frequently hitting with modern
access points; this limitation would can be lifted after this
patch by sending the correct binary, not custom, event.

A similar problem apparently happens for some other netlink
users on x86_64 with 32-bit tasks due to the alignment for
64-bit quantities.

In order to fix these problems, I have implemented a way to
send compat messages to tasks. When sending an event, we send
the non-compat event data together with a compat event data in
skb_shinfo(main_skb)->frag_list. Then, when the event is read
from the socket, the netlink code makes sure to pass out only
the skb that is compatible with the task. This approach was
suggested by David Miller, my original approach required
always sending two skbs but that had various small problems.

To determine whether compat is needed or not, I have used the
MSG_CMSG_COMPAT flag, and adjusted the call path for recv and
recvfrom to include it, even if those calls do not have a cmsg
parameter.

I have not solved one small part of the problem, and I don't
think it is necessary to: if a 32-bit application uses read()
rather than any form of recvmsg() it will still get the wrong
(64-bit) event. However, neither do applications actually do
this, nor would it be a regression.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1dacc76d
  51. 13 7月, 2009 2 次提交
  53. 18 6月, 2009 1 次提交
  55. 25 3月, 2009 1 次提交
    • P
      netlink: add NETLINK_NO_ENOBUFS socket flag · 38938bfe
      由 Pablo Neira Ayuso 提交于 
      This patch adds the NETLINK_NO_ENOBUFS socket flag. This flag can
be used by unicast and broadcast listeners to avoid receiving
ENOBUFS errors.

Generally speaking, ENOBUFS errors are useful to notify two things
to the listener:

a) You may increase the receiver buffer size via setsockopt().
b) You have lost messages, you may be out of sync.

In some cases, ignoring ENOBUFS errors can be useful. For example:

a) nfnetlink_queue: this subsystem does not have any sort of resync
method and you can decide to ignore ENOBUFS once you have set a
given buffer size.

b) ctnetlink: you can use this together with the socket flag
NETLINK_BROADCAST_SEND_ERROR to stop getting ENOBUFS errors as
you do not need to resync (packets whose event are not delivered
are drop to provide reliable logging and state-synchronization).

Moreover, the use of NETLINK_NO_ENOBUFS also reduces a "go up, go down"
effect in terms of performance which is due to the netlink congestion
control when the listener cannot back off. The effect is the following:

1) throughput rate goes up and netlink messages are inserted in the
receiver buffer.
2) Then, netlink buffer fills and overruns (set on nlk->state bit 0).
3) While the listener empties the receiver buffer, netlink keeps
dropping messages. Thus, throughput goes dramatically down.
4) Then, once the listener has emptied the buffer (nlk->state
bit 0 is set off), goto step 1.

This effect is easy to trigger with netlink broadcast under heavy
load, and it is more noticeable when using a big receiver buffer.
You can find some results in [1] that show this problem.

[1] http://1984.lsi.us.es/linux/netlink/

This patch also includes the use of sk_drop to account the number of
netlink messages drop due to overrun. This value is shown in
/proc/net/netlink.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      38938bfe
  57. 23 3月, 2009 1 次提交
  59. 04 3月, 2009 1 次提交
    • P
      netlink: invert error code in netlink_set_err() · 4843b93c
      由 Pablo Neira Ayuso 提交于 
      The callers of netlink_set_err() currently pass a negative value
as parameter for the error code. However, sk->sk_err wants a
positive error value. Without this patch, skb_recv_datagram() called
by netlink_recvmsg() may return a positive value to report an error.

Another choice to fix this is to change callers to pass a positive
error value, but this seems a bit inconsistent and error prone
to me. Indeed, the callers of netlink_set_err() assumed that the
(usual) negative value for error codes was fine before this patch :).

This patch also includes some documentation in docbook format
for netlink_set_err() to avoid this sort of confusion.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4843b93c
  61. 27 2月, 2009 1 次提交
  63. 25 2月, 2009 1 次提交
    • P
      netlink: change nlmsg_notify() return value logic · 1ce85fe4
      由 Pablo Neira Ayuso 提交于 
      This patch changes the return value of nlmsg_notify() as follows:

If NETLINK_BROADCAST_ERROR is set by any of the listeners and
an error in the delivery happened, return the broadcast error;
else if there are no listeners apart from the socket that
requested a change with the echo flag, return the result of the
unicast notification. Thus, with this patch, the unicast
notification is handled in the same way of a broadcast listener
that has set the NETLINK_BROADCAST_ERROR socket flag.

This patch is useful in case that the caller of nlmsg_notify()
wants to know the result of the delivery of a netlink notification
(including the broadcast delivery) and take any action in case
that the delivery failed. For example, ctnetlink can drop packets
if the event delivery failed to provide reliable logging and
state-synchronization at the cost of dropping packets.

This patch also modifies the rtnetlink code to ignore the return
value of rtnl_notify() in all callers. The function rtnl_notify()
(before this patch) returned the error of the unicast notification
which makes rtnl_set_sk_err() reports errors to all listeners. This
is not of any help since the origin of the change (the socket that
requested the echoing) notices the ENOBUFS error if the notification
fails and should resync itself.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1ce85fe4
  65. 20 2月, 2009 1 次提交
    • P
      netlink: add NETLINK_BROADCAST_ERROR socket option · be0c22a4
      由 Pablo Neira Ayuso 提交于 
      This patch adds NETLINK_BROADCAST_ERROR which is a netlink
socket option that the listener can set to make netlink_broadcast()
return errors in the delivery to the caller. This option is useful
if the caller of netlink_broadcast() do something with the result
of the message delivery, like in ctnetlink where it drops a network
packet if the event delivery failed, this is used to enable reliable
logging and state-synchronization. If this socket option is not set,
netlink_broadcast() only reports ESRCH errors and silently ignore
ENOBUFS errors, which is what most netlink_broadcast() callers
should do.

This socket option is based on a suggestion from Patrick McHardy.
Patrick McHardy can exchange this patch for a beer from me ;).
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      be0c22a4
  67. 06 2月, 2009 1 次提交
    • P
      netlink: change return-value logic of netlink_broadcast() · ff491a73
      由 Pablo Neira Ayuso 提交于 
      Currently, netlink_broadcast() reports errors to the caller if no
messages at all were delivered:

1) If, at least, one message has been delivered correctly, returns 0.
2) Otherwise, if no messages at all were delivered due to skb_clone()
   failure, return -ENOBUFS.
3) Otherwise, if there are no listeners, return -ESRCH.

With this patch, the caller knows if the delivery of any of the
messages to the listeners have failed:

1) If it fails to deliver any message (for whatever reason), return
   -ENOBUFS.
2) Otherwise, if all messages were delivered OK, returns 0.
3) Otherwise, if no listeners, return -ESRCH.

In the current ctnetlink code and in Netfilter in general, we can add
reliable logging and connection tracking event delivery by dropping the
packets whose events were not successfully delivered over Netlink. Of
course, this option would be settable via /proc as this approach reduces
performance (in terms of filtered connections per seconds by a stateful
firewall) but providing reliable logging and event delivery (for
conntrackd) in return.

This patch also changes some clients of netlink_broadcast() that
may report ENOBUFS errors via printk. This error handling is not
of any help. Instead, the userspace daemons that are listening to
those netlink messages should resync themselves with the kernel-side
if they hit ENOBUFS.

BTW, netlink_broadcast() clients include those that call
cn_netlink_send(), nlmsg_multicast() and genlmsg_multicast() since they
internally call netlink_broadcast() and return its error value.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ff491a73
  69. 25 11月, 2008 1 次提交
  71. 24 11月, 2008 2 次提交
  73. 17 10月, 2008 1 次提交
  75. 14 10月, 2008 1 次提交