linux-stable.git/arch/arm/kernel, branch v3.10.7

ARM: fix nommu builds with 48be69a02 (ARM: move signal handlers into a vdso-like page)

2013-08-12T01:35:20+00:00

commit 8c0cc8a5d90bc7373a7a9e7f7a40eb41f51e03fc upstream.

Olof reports that noMMU builds error out with:

arch/arm/kernel/signal.c: In function 'setup_return':
arch/arm/kernel/signal.c:413:25: error: 'mm_context_t' has no member named 'sigpage'

This shows one of the evilnesses of IS_ENABLED().  Get rid of it here
and replace it with #ifdef's - and as no noMMU platform can make use
of sigpage, depend on CONIFG_MMU not CONFIG_ARM_MPU.

Reported-by: Olof Johansson 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: fix a cockup in 48be69a02 (ARM: move signal handlers into a vdso-like page)

2013-08-12T01:35:20+00:00

commit e0d407564b532d978b03ceccebd224a05d02f111 upstream.

Unfortunately, I never committed the fix to a nasty oops which can
occur as a result of that commit:

------------[ cut here ]------------
kernel BUG at /home/olof/work/batch/include/linux/mm.h:414!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 490 Comm: killall5 Not tainted 3.11.0-rc3-00288-gabe0308 #53
task: e90acac0 ti: e9be8000 task.ti: e9be8000
PC is at special_mapping_fault+0xa4/0xc4
LR is at __do_fault+0x68/0x48c

This doesn't show up unless you do quite a bit of testing; a simple
boot test does not do this, so all my nightly tests were passing fine.

The reason for this is that install_special_mapping() expects the
page array to stick around, and as this was only inserting one page
which was stored on the kernel stack, that's why this was blowing up.

Reported-by: Olof Johansson 
Tested-by: Olof Johansson 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: make vectors page inaccessible from userspace

2013-08-12T01:35:20+00:00

commit a5463cd3435475386cbbe7b06e01292ac169d36f upstream.

If kuser helpers are not provided by the kernel, disable user access to
the vectors page.  With the kuser helpers gone, there is no reason for
this page to be visible to userspace.

Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: move signal handlers into a vdso-like page

2013-08-12T01:35:20+00:00

commit 48be69a026b2c17350a5ef18a1959a919f60be7d upstream.

Move the signal handlers into a VDSO page rather than keeping them in
the vectors page.  This allows us to place them randomly within this
page, and also map the page at a random location within userspace
further protecting these code fragments from ROP attacks.  The new
VDSO page is also poisoned in the same way as the vector page.

Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: allow kuser helpers to be removed from the vector page

2013-08-12T01:35:20+00:00

commit f6f91b0d9fd971c630cef908dde8fe8795aefbf8 upstream.

Provide a kernel configuration option to allow the kernel user helpers
to be removed from the vector page, thereby preventing their use with
ROP (return orientated programming) attacks.  This option is only
visible for CPU architectures which natively support all the operations
which kernel user helpers would normally provide, and must be enabled
with caution.

Acked-by: Nicolas Pitre 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: update FIQ support for relocation of vectors

2013-08-12T01:35:20+00:00

commit e39e3f3ebfef03450cf7bfa7a974a8c61f7980c8 upstream.

FIQ should no longer copy the FIQ code into the user visible vector
page.  Instead, it should use the hidden page.  This change makes
that happen.

Acked-by: Nicolas Pitre 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: use linker magic for vectors and vector stubs

2013-08-12T01:35:20+00:00

commit b9b32bf70f2fb710b07c94e13afbc729afe221da upstream.

Use linker magic to create the vectors and vector stubs: we can tell the
linker to place them at an appropriate VMA, but keep the LMA within the
kernel.  This gets rid of some unnecessary symbol manipulation, and
have the linker calculate the relocations appropriately.

Acked-by: Nicolas Pitre 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: move vector stubs

2013-08-12T01:35:20+00:00

commit 19accfd373847ac3d10623c5d20f948846299741 upstream.

Move the machine vector stubs into the page above the vector page,
which we can prevent from being visible to userspace.  Also move
the reset stub, and place the swi vector at a location that the
'ldr' can get to it.

This hides pointers into the kernel which could give valuable
information to attackers, and reduces the number of exploitable
instructions at a fixed address.

Acked-by: Nicolas Pitre 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: poison memory between kuser helpers

2013-08-12T01:35:20+00:00

commit 5b43e7a383d69381ffe53423e46dd0fafae07da3 upstream.

Poison the memory between each kuser helper.  This ensures that any
branch between the kuser helpers will be appropriately trapped.

Acked-by: Nicolas Pitre 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: poison the vectors page

2013-08-12T01:35:19+00:00

commit f928d4f2a86f46b030fa0850385b4391fc2b5918 upstream.

Fill the empty regions of the vectors page with an exception generating
instruction.  This ensures that any inappropriate branch to the vector
page is appropriately trapped, rather than just encountering some code
to execute.  (The vectors page was filled with zero before, which
corresponds with the "andeq r0, r0, r0" instruction - a no-op.)

Acked-by Nicolas Pitre 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman