linux-toradex.git/arch, branch v4.9.34

mm: larger stack guard gap, between vmas

2017-06-24T05:11:18+00:00

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov 
Original-patch-by: Michal Hocko 
Signed-off-by: Hugh Dickins 
Acked-by: Michal Hocko 
Tested-by: Helge Deller  # parisc
Signed-off-by: Linus Torvalds 
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
Signed-off-by: Willy Tarreau 
Signed-off-by: Greg Kroah-Hartman

MIPS: .its targets depend on vmlinux

2017-06-24T05:11:17+00:00

commit bcd7c45e0d5a82be9a64b90050f0e09d41a50758 upstream.

The .its targets require information about the kernel binary, such as
its entry point, which is extracted from the vmlinux ELF. We therefore
require that the ELF is built before the .its files are generated.
Declare this requirement in the Makefile such that make will ensure this
is always the case, otherwise in corner cases we can hit issues as the
.its is generated with an incorrect (either invalid or stale) entry
point.

Signed-off-by: Paul Burton 
Fixes: cf2a5e0bb4c6 ("MIPS: Support generating Flattened Image Trees (.itb)")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16179/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: Fix bnezc/jialc return address calculation

2017-06-24T05:11:17+00:00

commit 1a73d9310e093fc3adffba4d0a67b9fab2ee3f63 upstream.

The code handling the pop76 opcode (ie. bnezc & jialc instructions) in
__compute_return_epc_for_insn() needs to set the value of $31 in the
jialc case, which is encoded with rs = 0. However its check to
differentiate bnezc (rs != 0) from jialc (rs = 0) was unfortunately
backwards, meaning that if we emulate a bnezc instruction we clobber $31
& if we emulate a jialc instruction it actually behaves like a jic
instruction.

Fix this by inverting the check of rs to match the way the instructions
are actually encoded.

Signed-off-by: Paul Burton 
Fixes: 28d6f93d201d ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16178/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

x86/mm/32: Set the '__vmalloc_start_set' flag in initmem_init()

2017-06-24T05:11:14+00:00

commit 861ce4a3244c21b0af64f880d5bfe5e6e2fb9e4a upstream.

'__vmalloc_start_set' currently only gets set in initmem_init() when
!CONFIG_NEED_MULTIPLE_NODES. This breaks detection of vmalloc address
with virt_addr_valid() with CONFIG_NEED_MULTIPLE_NODES=y, causing
a kernel crash:

  [mm/usercopy] 517e1fbeb6: kernel BUG at arch/x86/mm/physaddr.c:78!

Set '__vmalloc_start_set' appropriately for that case as well.

Reported-by: kbuild test robot 
Signed-off-by: Laura Abbott 
Reviewed-by: Kees Cook 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: dc16ecf7fd1f ("x86-32: use specific __vmalloc_start_set flag in __virt_addr_valid")
Link: http://lkml.kernel.org/r/1494278596-30373-1-git-send-email-labbott@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

sparc64: make string buffers large enough

2017-06-17T04:41:58+00:00

commit b5c3206190f1fddd100b3060eb15f0d775ffeab8 upstream.

My static checker complains that if "lvl" is ULONG_MAX (this is 64 bit)
then some of the strings will overflow.  I don't know if that's possible
but it seems simple enough to make the buffers slightly larger.

Signed-off-by: Dan Carpenter 
Signed-off-by: David S. Miller 
Cc: Waldemar Brodkorb 
Signed-off-by: Greg Kroah-Hartman

s390/kvm: do not rely on the ILC on kvm host protection fauls

2017-06-17T04:41:58+00:00

commit c0e7bb38c07cbd8269549ee0a0566021a3c729de upstream.

For most cases a protection exception in the host (e.g. copy
on write or dirty tracking) on the sie instruction will indicate
an instruction length of 4. Turns out that there are some corner
cases (e.g. runtime instrumentation) where this is not necessarily
true and the ILC is unpredictable.

Let's replace our 4 byte rewind_pad with 3 byte nops to prepare for
all possible ILCs.

Signed-off-by: Christian Borntraeger 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

xtensa: don't use linux IRQ #0

2017-06-17T04:41:58+00:00

commit e5c86679d5e864947a52fb31e45a425dea3e7fa9 upstream.

Linux IRQ #0 is reserved for error reporting and may not be used.
Increase NR_IRQS for one additional slot and increase
irq_domain_add_legacy parameter first_irq value to 1, so that linux
IRQ #0 is not associated with hardware IRQ #0 in legacy IRQ domains.
Introduce macro XTENSA_PIC_LINUX_IRQ for static translation of xtensa
PIC hardware IRQ # to linux IRQ #. Use this macro in XTFPGA platform
data definitions.

This fixes inability to use hardware IRQ #0 in configurations that don't
use device tree and allows for non-identity mapping between linux IRQ #
and hardware IRQ #.

Signed-off-by: Max Filippov 
Signed-off-by: Greg Kroah-Hartman

ARCv2: smp-boot: wake_flag polling by non-Masters needs to be uncached

2017-06-17T04:41:57+00:00

[ Upstream commit 78f824d4312a8944f5340c6b161bba3bf2c81096 ]

This is needed on HS38 cores, for setting up IO-Coherency aperture properly

The polling could perturb the caches and coherecy fabric which could be
wrong in the small window when Master is setting up IOC aperture etc
in arc_cache_init()

We do it only for ARCv2 based builds to not affect EZChip ARCompact
based platform.

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

ARC: smp-boot: Decouple Non masters waiting API from jump to entry point

2017-06-17T04:41:57+00:00

[ Upstream commit bf02454a741b58682a82c314a9a46bed930ed2f7 ]

For run-on-reset SMP configs, non master cores call a routine which
waits until Master gives it a "go" signal (currently using a shared
mem flag). The same routine then jumps off the well known entry point of
all non Master cores i.e. @first_lines_of_secondary

This patch moves out the last part into one single place in early boot
code.

This is better in terms of absraction (the wait API only waits) and
returns, leaving out the "jump off to" part.

In actual implementation this requires some restructuring of the early
boot code as well as Master now jumps to BSS setup explicitly,
vs. falling thru into it before.

Technically this patch doesn't cause any functional change, it just
moves the ugly #ifdef'ry from assembly code to "C"

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

frv: add missing atomic64 operations

2017-06-17T04:41:56+00:00

[ Upstream commit 4180c4c170a5a33b9987b314d248a9d572d89ab0 ]

Some more atomic64 operations were missing and as a result frv
allmodconfig was failing.  Add the missing operations.

Link: http://lkml.kernel.org/r/1485193844-12850-1-git-send-email-sudip.mukherjee@codethink.co.uk
Signed-off-by: Sudip Mukherjee 
Cc: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman