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Filename Latest commit message Latest commit date
Xin Long f8a894b218 ipv6: fix calling in6_ifa_hold incorrectly for dad work
Now when starting the dad work in addrconf_mod_dad_work, if the dad work
is idle and queued, it needs to hold ifa.

The problem is there's one gap in [1], during which if the pending dad work
is removed elsewhere. It will miss to hold ifa, but the dad word is still
idea and queue.

        if (!delayed_work_pending(&ifp->dad_work))
                in6_ifa_hold(ifp);
                    <--------------[1]
        mod_delayed_work(addrconf_wq, &ifp->dad_work, delay);

An use-after-free issue can be caused by this.

Chen Wei found this issue when WARN_ON(!hlist_unhashed(&ifp->addr_lst)) in
net6_ifa_finish_destroy was hit because of it.

As Hannes' suggestion, this patch is to fix it by holding ifa first in
addrconf_mod_dad_work, then calling mod_delayed_work and putting ifa if
the dad_work is already in queue.

Note that this patch did not choose to fix it with:

  if (!mod_delayed_work(delay))
          in6_ifa_hold(ifp);

As with it, when delay == 0, dad_work would be scheduled immediately, all
addrconf_mod_dad_work(0) callings had to be moved under ifp->lock.

Reported-by: Wei Chen <weichen@redhat.com>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-15 11:26:16 -04:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-15 18:09:47 +09:00
block
certs
crypto
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-15 18:09:47 +09:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-15 18:09:47 +09:00
firmware
fs Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-06-15 17:54:51 +09:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-15 18:09:47 +09:00
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lib Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-06-15 17:54:51 +09:00
mm
net ipv6: fix calling in6_ifa_hold incorrectly for dad work 2017-06-15 11:26:16 -04:00
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tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-15 18:09:47 +09:00
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Linux kernel
============

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Please notice that there are several guides for kernel developers and users.
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There are various text files in the Documentation/ subdirectory,
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See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.