1. 20 Oct, 2015 22 commits
  2. 13 Oct, 2015 4 commits
    • Marcelo Ricardo Leitner's avatar
      sctp: fix race on protocol/netns initialization · 75113254
      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>
      75113254
    • Eric W. Biederman's avatar
      vfs: Test for and handle paths that are unreachable from their mnt_root · 29da259e
      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>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      29da259e
    • Eric W. Biederman's avatar
      dcache: Handle escaped paths in prepend_path · df50ffca
      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>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      df50ffca
    • Johan Hovold's avatar
      USB: whiteheat: fix potential null-deref at probe · 28f76f92
      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>
      28f76f92
  3. 25 Sep, 2015 1 commit
  4. 22 Sep, 2015 8 commits
  5. 21 Sep, 2015 5 commits
    • David S. Miller's avatar
      sparc64: Fix userspace FPU register corruptions. · 31de7bfa
      David S. Miller authored
      [ Upstream commit 44922150 ]
      
      If we have a series of events from userpsace, with %fprs=FPRS_FEF,
      like follows:
      
      ETRAP
      	ETRAP
      		VIS_ENTRY(fprs=0x4)
      		VIS_EXIT
      		RTRAP (kernel FPU restore with fpu_saved=0x4)
      	RTRAP
      
      We will not restore the user registers that were clobbered by the FPU
      using kernel code in the inner-most trap.
      
      Traps allocate FPU save slots in the thread struct, and FPU using
      sequences save the "dirty" FPU registers only.
      
      This works at the initial trap level because all of the registers
      get recorded into the top-level FPU save area, and we'll return
      to userspace with the FPU disabled so that any FPU use by the user
      will take an FPU disabled trap wherein we'll load the registers
      back up properly.
      
      But this is not how trap returns from kernel to kernel operate.
      
      The simplest fix for this bug is to always save all FPU register state
      for anything other than the top-most FPU save area.
      
      Getting rid of the optimized inner-slot FPU saving code ends up
      making VISEntryHalf degenerate into plain VISEntry.
      
      Longer term we need to do something smarter to reinstate the partial
      save optimizations.  Perhaps the fundament error is having trap entry
      and exit allocate FPU save slots and restore register state.  Instead,
      the VISEntry et al. calls should be doing that work.
      
      This bug is about two decades old.
      Reported-by: default avatarJames Y Knight <jyknight@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      31de7bfa
    • Eric Dumazet's avatar
      udp: fix dst races with multicast early demux · 9625566c
      Eric Dumazet authored
      commit 10e2eb87 upstream.
      
      Multicast dst are not cached. They carry DST_NOCACHE.
      
      As mentioned in commit f8864972 ("ipv4: fix dst race in
      sk_dst_get()"), these dst need special care before caching them
      into a socket.
      
      Caching them is allowed only if their refcnt was not 0, ie we
      must use atomic_inc_not_zero()
      
      Also, we must use READ_ONCE() to fetch sk->sk_rx_dst, as mentioned
      in commit d0c294c5 ("tcp: prevent fetching dst twice in early demux
      code")
      
      Fixes: 421b3885 ("udp: ipv4: Add udp early demux")
      Tested-by: default avatarGregory Hoggarth <Gregory.Hoggarth@alliedtelesis.co.nz>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reported-by: default avatarGregory Hoggarth <Gregory.Hoggarth@alliedtelesis.co.nz>
      Reported-by: default avatarAlex Gartrell <agartrell@fb.com>
      Cc: Michal Kubeček <mkubecek@suse.cz>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      [ luis: backported to 3.16: used davem's backport to 3.14 ]
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      9625566c
    • Dan Carpenter's avatar
      rds: fix an integer overflow test in rds_info_getsockopt() · 950a7a69
      Dan Carpenter authored
      commit 468b732b upstream.
      
      "len" is a signed integer.  We check that len is not negative, so it
      goes from zero to INT_MAX.  PAGE_SIZE is unsigned long so the comparison
      is type promoted to unsigned long.  ULONG_MAX - 4095 is a higher than
      INT_MAX so the condition can never be true.
      
      I don't know if this is harmful but it seems safe to limit "len" to
      INT_MAX - 4095.
      
      Fixes: a8c879a7 ('RDS: Info and stats')
      Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      950a7a69
    • Herbert Xu's avatar
      net: Fix skb_set_peeked use-after-free bug · 1f61c92c
      Herbert Xu authored
      commit a0a2a660 upstream.
      
      The commit 738ac1eb ("net: Clone
      skb before setting peeked flag") introduced a use-after-free bug
      in skb_recv_datagram.  This is because skb_set_peeked may create
      a new skb and free the existing one.  As it stands the caller will
      continue to use the old freed skb.
      
      This patch fixes it by making skb_set_peeked return the new skb
      (or the old one if unchanged).
      
      Fixes: 738ac1eb ("net: Clone skb before setting peeked flag")
      Reported-by: default avatarBrenden Blanco <bblanco@plumgrid.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      Tested-by: default avatarBrenden Blanco <bblanco@plumgrid.com>
      Reviewed-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      1f61c92c
    • David Ahern's avatar
      net: Fix RCU splat in af_key · 815c0610
      David Ahern authored
      commit ba51b6be upstream.
      
      Hit the following splat testing VRF change for ipsec:
      
      [  113.475692] ===============================
      [  113.476194] [ INFO: suspicious RCU usage. ]
      [  113.476667] 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED Not tainted
      [  113.477545] -------------------------------
      [  113.478013] /work/monster-14/dsa/kernel.git/include/linux/rcupdate.h:568 Illegal context switch in RCU read-side critical section!
      [  113.479288]
      [  113.479288] other info that might help us debug this:
      [  113.479288]
      [  113.480207]
      [  113.480207] rcu_scheduler_active = 1, debug_locks = 1
      [  113.480931] 2 locks held by setkey/6829:
      [  113.481371]  #0:  (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff814e9887>] pfkey_sendmsg+0xfb/0x213
      [  113.482509]  #1:  (rcu_read_lock){......}, at: [<ffffffff814e767f>] rcu_read_lock+0x0/0x6e
      [  113.483509]
      [  113.483509] stack backtrace:
      [  113.484041] CPU: 0 PID: 6829 Comm: setkey Not tainted 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED
      [  113.485422] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014
      [  113.486845]  0000000000000001 ffff88001d4c7a98 ffffffff81518af2 ffffffff81086962
      [  113.487732]  ffff88001d538480 ffff88001d4c7ac8 ffffffff8107ae75 ffffffff8180a154
      [  113.488628]  0000000000000b30 0000000000000000 00000000000000d0 ffff88001d4c7ad8
      [  113.489525] Call Trace:
      [  113.489813]  [<ffffffff81518af2>] dump_stack+0x4c/0x65
      [  113.490389]  [<ffffffff81086962>] ? console_unlock+0x3d6/0x405
      [  113.491039]  [<ffffffff8107ae75>] lockdep_rcu_suspicious+0xfa/0x103
      [  113.491735]  [<ffffffff81064032>] rcu_preempt_sleep_check+0x45/0x47
      [  113.492442]  [<ffffffff8106404d>] ___might_sleep+0x19/0x1c8
      [  113.493077]  [<ffffffff81064268>] __might_sleep+0x6c/0x82
      [  113.493681]  [<ffffffff81133190>] cache_alloc_debugcheck_before.isra.50+0x1d/0x24
      [  113.494508]  [<ffffffff81134876>] kmem_cache_alloc+0x31/0x18f
      [  113.495149]  [<ffffffff814012b5>] skb_clone+0x64/0x80
      [  113.495712]  [<ffffffff814e6f71>] pfkey_broadcast_one+0x3d/0xff
      [  113.496380]  [<ffffffff814e7b84>] pfkey_broadcast+0xb5/0x11e
      [  113.497024]  [<ffffffff814e82d1>] pfkey_register+0x191/0x1b1
      [  113.497653]  [<ffffffff814e9770>] pfkey_process+0x162/0x17e
      [  113.498274]  [<ffffffff814e9895>] pfkey_sendmsg+0x109/0x213
      
      In pfkey_sendmsg the net mutex is taken and then pfkey_broadcast takes
      the RCU lock.
      
      Since pfkey_broadcast takes the RCU lock the allocation argument is
      pointless since GFP_ATOMIC must be used between the rcu_read_{,un}lock.
      The one call outside of rcu can be done with GFP_KERNEL.
      
      Fixes: 7f6b9dbd ("af_key: locking change")
      Signed-off-by: default avatarDavid Ahern <dsa@cumulusnetworks.com>
      Acked-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      815c0610