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  1. 13 2月, 2008 10 次提交
    • D
      [NDISC]: Fix race in generic address resolution · 69cc64d8
      由 David S. Miller 提交于 
      Frank Blaschka provided the bug report and the initial suggested fix
for this bug.  He also validated this version of this fix.

The problem is that the access to neigh->arp_queue is inconsistent, we
grab references when dropping the lock lock to call
neigh->ops->solicit() but this does not prevent other threads of
control from trying to send out that packet at the same time causing
corruptions because both code paths believe they have exclusive access
to the skb.

The best option seems to be to hold the write lock on neigh->lock
during the ->solicit() call.  I looked at all of the ndisc_ops
implementations and this seems workable.  The only case that needs
special care is the IPV4 ARP implementation of arp_solicit().  It
wants to take neigh->lock as a reader to protect the header entry in
neigh->ha during the emission of the soliciation.  We can simply
remove the read lock calls to take care of that since holding the lock
as a writer at the caller providers a superset of the protection
afforded by the existing read locking.

The rest of the ->solicit() implementations don't care whether the
neigh is locked or not.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      69cc64d8
    • D
      hci_ldisc: fix null pointer deref · 3611f4d2
      由 David Newall 提交于 
      Arjan:

  With the help of kerneloops.org I've spotted a nice little interaction
  between the TTY layer and the bluetooth code, however the tty layer is not
  something I'm all too familiar with so I rather ask than brute-force fix the
  code incorrectly.

  The raw details are at:
  http://www.kerneloops.org/search.php?search=uart_flush_buffer

  What happens is that, on closing the bluetooth tty, the tty layer goes
  into the release_dev() function, which first does a bunch of stuff, then
  sets the file->private_data to NULL, does some more stuff and then calls the
  ldisc close function.  Which in this case, is hci_uart_tty_close().

  Now, hci_uart_tty_close() calls hci_uart_close() which clears some
  internal bit, and then calls hci_uart_flush()...  which calls back to the
  tty layers' uart_flush_buffer() function.  (in drivers/bluetooth/hci_tty.c
  around line 194) Which then WARN_ON()'s because that's not allowed/supposed
  to be called this late in the shutdown of the port....

  Should the bluetooth driver even call this flush function at all??

David:

  This seems to be what happens: Hci_uart_close() flushes using
  hci_uart_flush().  Subsequently, in hci_dev_do_close(), (one step in
  hci_unregister_dev()), hci_uart_flush() is called again.  The comment in
  uart_flush_buffer(), relating to the WARN_ON(), indicates you can't flush
  after the port is closed; which sounds reasonable.  I think hci_uart_close()
  should set hdev->flush to NULL before returning.  Hci_dev_do_close() does
  check for this.  The code path is rather involved and I'm not entirely clear
  of all steps, but I think that's what should be done.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3611f4d2
    • J
      [AX25] ax25_ds_timer: use mod_timer instead of add_timer · e848b583
      由 Jarek Poplawski 提交于 
      This patch changes current use of: init_timer(), add_timer()
and del_timer() to setup_timer() with mod_timer(), which
should be safer anyway.
Reported-by: NJann Traschewski <jann@gmx.de>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e848b583
    • J
      [AX25] ax25_timer: use mod_timer instead of add_timer · 21fab4a8
      由 Jarek Poplawski 提交于 
      According to one of Jann's OOPS reports it looks like
BUG_ON(timer_pending(timer)) triggers during add_timer()
in ax25_start_t1timer(). This patch changes current use
of: init_timer(), add_timer() and del_timer() to
setup_timer() with mod_timer(), which should be safer
anyway.
Reported-by: NJann Traschewski <jann@gmx.de>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      21fab4a8
    • J
      [AX25] ax25_route: make ax25_route_lock BH safe · 4de211f1
      由 Jarek Poplawski 提交于 
      > =================================
> [ INFO: inconsistent lock state ]
> 2.6.24-dg8ngn-p02 #1
> ---------------------------------
> inconsistent {softirq-on-W} -> {in-softirq-R} usage.
> linuxnet/3046 [HC0[0]:SC1[2]:HE1:SE0] takes:
>  (ax25_route_lock){--.+}, at: [<f8a0cfb7>] ax25_get_route+0x18/0xb7 [ax25]
> {softirq-on-W} state was registered at:
...

This lockdep report shows that ax25_route_lock is taken for reading in
softirq context, and for writing in process context with BHs enabled.
So, to make this safe, all write_locks in ax25_route.c are changed to
_bh versions.

Reported-by: Jann Traschewski <jann@gmx.de>,
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4de211f1
    • J
      [AX25] af_ax25: remove sock lock in ax25_info_show() · 1105b5d1
      由 Jarek Poplawski 提交于 
      This lockdep warning:

> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.24 #3
> -------------------------------------------------------
> swapper/0 is trying to acquire lock:
>  (ax25_list_lock){-+..}, at: [<f91dd3b1>] ax25_destroy_socket+0x171/0x1f0 [ax25]
>
> but task is already holding lock:
>  (slock-AF_AX25){-+..}, at: [<f91dbabc>] ax25_std_heartbeat_expiry+0x1c/0xe0 [ax25]
>
> which lock already depends on the new lock.
...

shows that ax25_list_lock and slock-AF_AX25 are taken in different
order: ax25_info_show() takes slock (bh_lock_sock(ax25->sk)) while
ax25_list_lock is held, so reversely to other functions. To fix this
the sock lock should be moved to ax25_info_start(), and there would
be still problem with breaking ax25_list_lock (it seems this "proper"
order isn't optimal yet). But, since it's only for reading proc info
it seems this is not necessary (e.g.  ax25_send_to_raw() does similar
reading without this lock too).

So, this patch removes sock lock to avoid deadlock possibility; there
is also used sock_i_ino() function, which reads sk_socket under proper
read lock. Additionally printf format of this i_ino is changed to %lu.
Reported-by: NBernard Pidoux F6BVP <f6bvp@free.fr>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1105b5d1
    • S
      fib_trie: /proc/net/route performance improvement · 8315f5d8
      由 Stephen Hemminger 提交于 
      Use key/offset caching to change /proc/net/route (use by iputils route)
from O(n^2) to O(n). This improves performance from 30sec with 160,000
routes to 1sec.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8315f5d8
    • S
      fib_trie: handle empty tree · ec28cf73
      由 Stephen Hemminger 提交于 
      This fixes possible problems when trie_firstleaf() returns NULL
to trie_leafindex().
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ec28cf73
    • D
      [IPV4]: Remove IP_TOS setting privilege checks. · e4f8b5d4
      由 David S. Miller 提交于 
      Various RFCs have all sorts of things to say about the CS field of the
DSCP value.  In particular they try to make the distinction between
values that should be used by "user applications" and things like
routing daemons.

This seems to have influenced the CAP_NET_ADMIN check which exists for
IP_TOS socket option settings, but in fact it has an off-by-one error
so it wasn't allowing CS5 which is meant for "user applications" as
well.

Further adding to the inconsistency and brokenness here, IPV6 does not
validate the DSCP values specified for the IPV6_TCLASS socket option.

The real actual uses of these TOS values are system specific in the
final analysis, and these RFC recommendations are just that, "a
recommendation".  In fact the standards very purposefully use
"SHOULD" and "SHOULD NOT" when describing how these values can be
used.

In the final analysis the only clean way to provide consistency here
is to remove the CAP_NET_ADMIN check.  The alternatives just don't
work out:

1) If we add the CAP_NET_ADMIN check to ipv6, this can break existing
   setups.

2) If we just fix the off-by-one error in the class comparison in
   IPV4, certain DSCP values can be used in IPV6 but not IPV4 by
   default.  So people will just ask for a sysctl asking to
   override that.

I checked several other freely available kernel trees and they
do not make any privilege checks in this area like we do.  For
the BSD stacks, this goes back all the way to Stevens Volume 2
and beyond.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e4f8b5d4
    • D
      Merge branch 'upstream-davem' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6 · b791dd3e
      由 David S. Miller 提交于
      b791dd3e
  3. 12 2月, 2008 30 次提交