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  1. 19 Oct, 2015 17 commits
  3. 13 Oct, 2015 4 commits
    • Marcelo Ricardo Leitner's avatar
      sctp: fix race on protocol/netns initialization · ac73bd07
      Marcelo Ricardo Leitner authored 
      commit 8e2d61e0 upstream.

Consider sctp module is unloaded and is being requested because an user
is creating a sctp socket.

During initialization, sctp will add the new protocol type and then
initialize pernet subsys:

        status = sctp_v4_protosw_init();
        if (status)
                goto err_protosw_init;

        status = sctp_v6_protosw_init();
        if (status)
                goto err_v6_protosw_init;

        status = register_pernet_subsys(&sctp_net_ops);

The problem is that after those calls to sctp_v{4,6}_protosw_init(), it
is possible for userspace to create SCTP sockets like if the module is
already fully loaded. If that happens, one of the possible effects is
that we will have readers for net->sctp.local_addr_list list earlier
than expected and sctp_net_init() does not take precautions while
dealing with that list, leading to a potential panic but not limited to
that, as sctp_sock_init() will copy a bunch of blank/partially
initialized values from net->sctp.

The race happens like this:

     CPU 0                           |  CPU 1
  socket()                           |
   __sock_create                     | socket()
    inet_create                      |  __sock_create
     list_for_each_entry_rcu(        |
        answer, &inetsw[sock->type], |
        list) {                      |   inet_create
      /* no hits */                  |
     if (unlikely(err)) {            |
      ...                            |
      request_module()               |
      /* socket creation is blocked  |
       * the module is fully loaded  |
       */                            |
       sctp_init                     |
        sctp_v4_protosw_init         |
         inet_register_protosw       |
          list_add_rcu(&p->list,     |
                       last_perm);   |
                                     |  list_for_each_entry_rcu(
                                     |     answer, &inetsw[sock->type],
        sctp_v6_protosw_init         |     list) {
                                     |     /* hit, so assumes protocol
                                     |      * is already loaded
                                     |      */
                                     |  /* socket creation continues
                                     |   * before netns is initialized
                                     |   */
        register_pernet_subsys       |

Simply inverting the initialization order between
register_pernet_subsys() and sctp_v4_protosw_init() is not possible
because register_pernet_subsys() will create a control sctp socket, so
the protocol must be already visible by then. Deferring the socket
creation to a work-queue is not good specially because we loose the
ability to handle its errors.

So, as suggested by Vlad, the fix is to split netns initialization in
two moments: defaults and control socket, so that the defaults are
already loaded by when we register the protocol, while control socket
initialization is kept at the same moment it is today.

Fixes: 4db67e80 ("sctp: Make the address lists per network namespace")
Signed-off-by: default avatarVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      ac73bd07
    • Eric W. Biederman's avatar
      vfs: Test for and handle paths that are unreachable from their mnt_root · d0b4cf04
      Eric W. Biederman authored 
      commit 397d425d upstream.

In rare cases a directory can be renamed out from under a bind mount.
In those cases without special handling it becomes possible to walk up
the directory tree to the root dentry of the filesystem and down
from the root dentry to every other file or directory on the filesystem.

Like division by zero .. from an unconnected path can not be given
a useful semantic as there is no predicting at which path component
the code will realize it is unconnected.  We certainly can not match
the current behavior as the current behavior is a security hole.

Therefore when encounting .. when following an unconnected path
return -ENOENT.

- Add a function path_connected to verify path->dentry is reachable
  from path->mnt.mnt_root.  AKA to validate that rename did not do
  something nasty to the bind mount.

  To avoid races path_connected must be called after following a path
  component to it's next path component.
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Reference: CVE-2015-2925
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      d0b4cf04
    • Eric W. Biederman's avatar
      dcache: Handle escaped paths in prepend_path · 6120521c
      Eric W. Biederman authored 
      commit cde93be4 upstream.

A rename can result in a dentry that by walking up d_parent
will never reach it's mnt_root.  For lack of a better term
I call this an escaped path.

prepend_path is called by four different functions __d_path,
d_absolute_path, d_path, and getcwd.

__d_path only wants to see paths are connected to the root it passes
in.  So __d_path needs prepend_path to return an error.

d_absolute_path similarly wants to see paths that are connected to
some root.  Escaped paths are not connected to any mnt_root so
d_absolute_path needs prepend_path to return an error greater
than 1.  So escaped paths will be treated like paths on lazily
unmounted mounts.

getcwd needs to prepend "(unreachable)" so getcwd also needs
prepend_path to return an error.

d_path is the interesting hold out.  d_path just wants to print
something, and does not care about the weird cases.  Which raises
the question what should be printed?

Given that <escaped_path>/<anything> should result in -ENOENT I
believe it is desirable for escaped paths to be printed as empty
paths.  As there are not really any meaninful path components when
considered from the perspective of a mount tree.

So tweak prepend_path to return an empty path with an new error
code of 3 when it encounters an escaped path.
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Reference: CVE-2015-2925
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      6120521c
    • Johan Hovold's avatar
      USB: whiteheat: fix potential null-deref at probe · 18647fe4
      Johan Hovold authored 
      commit cbb4be65 upstream.

Fix potential null-pointer dereference at probe by making sure that the
required endpoints are present.

The whiteheat driver assumes there are at least five pairs of bulk
endpoints, of which the final pair is used for the "command port". An
attempt to bind to an interface with fewer bulk endpoints would
currently lead to an oops.

Fixes CVE-2015-5257.
Reported-by: default avatarMoein Ghasemzadeh <moein@istuary.com>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      18647fe4
  5. 25 Sep, 2015 1 commit
  7. 24 Sep, 2015 2 commits
    • Jiang Liu's avatar
      ACPI, PCI: Penalize legacy IRQ used by ACPI SCI · b8fecc9f
      Jiang Liu authored 
      commit 5d0ddfeb upstream.

Nick Meier reported a regression with HyperV that "
  After rebooting the VM, the following messages are logged in syslog
  when trying to load the tulip driver:
    tulip: Linux Tulip drivers version 1.1.15 (Feb 27, 2007)
    tulip: 0000:00:0a.0: PCI INT A: failed to register GSI
    tulip: Cannot enable tulip board #0, aborting
    tulip: probe of 0000:00:0a.0 failed with error -16
  Errors occur in 3.19.0 kernel
  Works in 3.17 kernel.
"

According to the ACPI dump file posted by Nick at
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1440072

The ACPI MADT table includes an interrupt source overridden entry for
ACPI SCI:
[236h 0566  1]                Subtable Type : 02 <Interrupt Source Override>
[237h 0567  1]                       Length : 0A
[238h 0568  1]                          Bus : 00
[239h 0569  1]                       Source : 09
[23Ah 0570  4]                    Interrupt : 00000009
[23Eh 0574  2]        Flags (decoded below) : 000D
                                   Polarity : 1
                               Trigger Mode : 3

And in DSDT table, we have _PRT method to define PCI interrupts, which
eventually goes to:
        Name (PRSA, ResourceTemplate ()
        {
            IRQ (Level, ActiveLow, Shared, )
                {3,4,5,7,9,10,11,12,14,15}
        })
        Name (PRSB, ResourceTemplate ()
        {
            IRQ (Level, ActiveLow, Shared, )
                {3,4,5,7,9,10,11,12,14,15}
        })
        Name (PRSC, ResourceTemplate ()
        {
            IRQ (Level, ActiveLow, Shared, )
                {3,4,5,7,9,10,11,12,14,15}
        })
        Name (PRSD, ResourceTemplate ()
        {
            IRQ (Level, ActiveLow, Shared, )
                {3,4,5,7,9,10,11,12,14,15}
        })

According to the MADT and DSDT tables, IRQ 9 may be used for:
 1) ACPI SCI in level, high mode
 2) PCI legacy IRQ in level, low mode
So there's a conflict in polarity setting for IRQ 9.

Prior to commit cd68f6bd ("x86, irq, acpi: Get rid of special
handling of GSI for ACPI SCI"), ACPI SCI is handled specially and
there's no check for conflicts between ACPI SCI and PCI legagy IRQ.
And it seems that the HyperV hypervisor doesn't make use of the
polarity configuration in IOAPIC entry, so it just works.

Commit cd68f6bd gets rid of the specially handling of ACPI SCI,
and then the pin attribute checking code discloses the conflicts
between ACPI SCI and PCI legacy IRQ on HyperV virtual machine,
and rejects the request to assign IRQ9 to PCI devices.

So penalize legacy IRQ used by ACPI SCI and mark it unusable if ACPI
SCI attributes conflict with PCI IRQ attributes.

Please refer to following links for more information:
https://bugzilla.kernel.org/show_bug.cgi?id=101301
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1440072

Fixes: cd68f6bd ("x86, irq, acpi: Get rid of special handling of GSI for ACPI SCI")
Reported-and-tested-by: default avatarNick Meier <nmeier@microsoft.com>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      b8fecc9f
    • Eric Whitney's avatar
      ext4: fix loss of delalloc extent info in ext4_zero_range() · 68e8fb56
      Eric Whitney authored 
      commit 94426f4b upstream.

In ext4_zero_range(), removing a file's entire block range from the
extent status tree removes all records of that file's delalloc extents.
The delalloc accounting code uses this information, and its loss can
then lead to accounting errors and kernel warnings at writeback time and
subsequent file system damage.  This is most noticeable on bigalloc
file systems where code in ext4_ext_map_blocks() handles cases where
delalloc extents share clusters with a newly allocated extent.

Because we're not deleting a block range and are correctly updating the
status of its associated extent, there is no need to remove anything
from the extent status tree.

When this patch is combined with an unrelated bug fix for
ext4_zero_range(), kernel warnings and e2fsck errors reported during
xfstests runs on bigalloc filesystems are greatly reduced without
introducing regressions on other xfstests-bld test scenarios.
Signed-off-by: default avatarEric Whitney <enwlinux@gmail.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      68e8fb56
  9. 22 Sep, 2015 16 commits
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