linux-stable.git, branch v4.9.26

Linux 4.9.26

2017-05-03T15:36:50+00:00

ftrace/x86: Fix triple fault with graph tracing and suspend-to-ram

2017-05-03T15:36:39+00:00

commit 34a477e5297cbaa6ecc6e17c042a866e1cbe80d6 upstream.

On x86-32, with CONFIG_FIRMWARE and multiple CPUs, if you enable function
graph tracing and then suspend to RAM, it will triple fault and reboot when
it resumes.

The first fault happens when booting a secondary CPU:

startup_32_smp()
  load_ucode_ap()
    prepare_ftrace_return()
      ftrace_graph_is_dead()
        (accesses 'kill_ftrace_graph')

The early head_32.S code calls into load_ucode_ap(), which has an an
ftrace hook, so it calls prepare_ftrace_return(), which calls
ftrace_graph_is_dead(), which tries to access the global
'kill_ftrace_graph' variable with a virtual address, causing a fault
because the CPU is still in real mode.

The fix is to add a check in prepare_ftrace_return() to make sure it's
running in protected mode before continuing.  The check makes sure the
stack pointer is a virtual kernel address.  It's a bit of a hack, but
it's not very intrusive and it works well enough.

For reference, here are a few other (more difficult) ways this could
have potentially been fixed:

- Move startup_32_smp()'s call to load_ucode_ap() down to *after* paging
  is enabled.  (No idea what that would break.)

- Track down load_ucode_ap()'s entire callee tree and mark all the
  functions 'notrace'.  (Probably not realistic.)

- Pause graph tracing in ftrace_suspend_notifier_call() or bringup_cpu()
  or __cpu_up(), and ensure that the pause facility can be queried from
  real mode.

Reported-by: Paul Menzel 
Signed-off-by: Josh Poimboeuf 
Tested-by: Paul Menzel 
Reviewed-by: Steven Rostedt (VMware) 
Cc: "Rafael J . Wysocki" 
Cc: linux-acpi@vger.kernel.org
Cc: Borislav Petkov 
Cc: Len Brown 
Link: http://lkml.kernel.org/r/5c1272269a580660703ed2eccf44308e790c7a98.1492123841.git.jpoimboe@redhat.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

ARCv2: save r30 on kernel entry as gcc uses it for code-gen

2017-05-03T15:36:39+00:00

commit ecd43afdbe72017aefe48080631eb625e177ef4d upstream.

This is not exposed to userspace debugers yet, which can be done
independently as a seperate patch !

Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

net: can: usb: gs_usb: Fix buffer on stack

2017-05-03T15:36:39+00:00

commit b05c73bd1e3ec60357580eb042ee932a5ed754d5 upstream.

Allocate buffers on HEAP instead of STACK for local structures
that are to be sent using usb_control_msg().

Signed-off-by: Maksim Salau 
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Greg Kroah-Hartman

macsec: avoid heap overflow in skb_to_sgvec

2017-05-03T15:36:39+00:00

commit 4d6fa57b4dab0d77f4d8e9d9c73d1e63f6fe8fee upstream.

While this may appear as a humdrum one line change, it's actually quite
important. An sk_buff stores data in three places:

1. A linear chunk of allocated memory in skb->data. This is the easiest
   one to work with, but it precludes using scatterdata since the memory
   must be linear.
2. The array skb_shinfo(skb)->frags, which is of maximum length
   MAX_SKB_FRAGS. This is nice for scattergather, since these fragments
   can point to different pages.
3. skb_shinfo(skb)->frag_list, which is a pointer to another sk_buff,
   which in turn can have data in either (1) or (2).

The first two are rather easy to deal with, since they're of a fixed
maximum length, while the third one is not, since there can be
potentially limitless chains of fragments. Fortunately dealing with
frag_list is opt-in for drivers, so drivers don't actually have to deal
with this mess. For whatever reason, macsec decided it wanted pain, and
so it explicitly specified NETIF_F_FRAGLIST.

Because dealing with (1), (2), and (3) is insane, most users of sk_buff
doing any sort of crypto or paging operation calls a convenient function
called skb_to_sgvec (which happens to be recursive if (3) is in use!).
This takes a sk_buff as input, and writes into its output pointer an
array of scattergather list items. Sometimes people like to declare a
fixed size scattergather list on the stack; othertimes people like to
allocate a fixed size scattergather list on the heap. However, if you're
doing it in a fixed-size fashion, you really shouldn't be using
NETIF_F_FRAGLIST too (unless you're also ensuring the sk_buff and its
frag_list children arent't shared and then you check the number of
fragments in total required.)

Macsec specifically does this:

        size += sizeof(struct scatterlist) * (MAX_SKB_FRAGS + 1);
        tmp = kmalloc(size, GFP_ATOMIC);
        *sg = (struct scatterlist *)(tmp + sg_offset);
	...
        sg_init_table(sg, MAX_SKB_FRAGS + 1);
        skb_to_sgvec(skb, sg, 0, skb->len);

Specifying MAX_SKB_FRAGS + 1 is the right answer usually, but not if you're
using NETIF_F_FRAGLIST, in which case the call to skb_to_sgvec will
overflow the heap, and disaster ensues.

Signed-off-by: Jason A. Donenfeld 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ceph: fix recursion between ceph_set_acl() and __ceph_setattr()

2017-05-03T15:36:39+00:00

commit 8179a101eb5f4ef0ac9a915fcea9a9d3109efa90 upstream.

ceph_set_acl() calls __ceph_setattr() if the setacl operation needs
to modify inode's i_mode. __ceph_setattr() updates inode's i_mode,
then calls posix_acl_chmod().

The problem is that __ceph_setattr() calls posix_acl_chmod() before
sending the setattr request. The get_acl() call in posix_acl_chmod()
can trigger a getxattr request. The reply of the getxattr request
can restore inode's i_mode to its old value. The set_acl() call in
posix_acl_chmod() sees old value of inode's i_mode, so it calls
__ceph_setattr() again.

Link: http://tracker.ceph.com/issues/19688
Reported-by: Jerry Lee 
Signed-off-by: "Yan, Zheng" 
Reviewed-by: Jeff Layton 
Tested-by: Luis Henriques 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

nfsd: stricter decoding of write-like NFSv2/v3 ops

2017-05-03T15:36:38+00:00

commit 13bf9fbff0e5e099e2b6f003a0ab8ae145436309 upstream.

The NFSv2/v3 code does not systematically check whether we decode past
the end of the buffer.  This generally appears to be harmless, but there
are a few places where we do arithmetic on the pointers involved and
don't account for the possibility that a length could be negative.  Add
checks to catch these.

Reported-by: Tuomas Haanpää 
Reported-by: Ari Kauppi 
Reviewed-by: NeilBrown 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

nfsd4: minor NFSv2/v3 write decoding cleanup

2017-05-03T15:36:38+00:00

commit db44bac41bbfc0c0d9dd943092d8bded3c9db19b upstream.

Use a couple shortcuts that will simplify a following bugfix.

Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

nfsd: check for oversized NFSv2/v3 arguments

2017-05-03T15:36:38+00:00

commit e6838a29ecb484c97e4efef9429643b9851fba6e upstream.

A client can append random data to the end of an NFSv2 or NFSv3 RPC call
without our complaining; we'll just stop parsing at the end of the
expected data and ignore the rest.

Encoded arguments and replies are stored together in an array of pages,
and if a call is too large it could leave inadequate space for the
reply.  This is normally OK because NFS RPC's typically have either
short arguments and long replies (like READ) or long arguments and short
replies (like WRITE).  But a client that sends an incorrectly long reply
can violate those assumptions.  This was observed to cause crashes.

Also, several operations increment rq_next_page in the decode routine
before checking the argument size, which can leave rq_next_page pointing
well past the end of the page array, causing trouble later in
svc_free_pages.

So, following a suggestion from Neil Brown, add a central check to
enforce our expectation that no NFSv2/v3 call has both a large call and
a large reply.

As followup we may also want to rewrite the encoding routines to check
more carefully that they aren't running off the end of the page array.

We may also consider rejecting calls that have any extra garbage
appended.  That would be safer, and within our rights by spec, but given
the age of our server and the NFS protocol, and the fact that we've
never enforced this before, we may need to balance that against the
possibility of breaking some oddball client.

Reported-by: Tuomas Haanpää 
Reported-by: Ari Kauppi 
Reviewed-by: NeilBrown 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

Input: i8042 - add Clevo P650RS to the i8042 reset list

2017-05-03T15:36:38+00:00

commit 7c5bb4ac2b76d2a09256aec8a7d584bf3e2b0466 upstream.

Clevo P650RS and other similar devices require i8042 to be reset in order
to detect Synaptics touchpad.

Reported-by: Paweł Bylica 
Tested-by: Ed Bordin 
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=190301
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman