linux-stable.git/arch, branch v4.4.71

sparc: Fix -Wstringop-overflow warning

2017-06-07T10:05:56+00:00

[ Upstream commit deba804c90642c8ed0f15ac1083663976d578f54 ]

Greetings,

GCC 7 introduced the -Wstringop-overflow flag to detect buffer overflows
in calls to string handling functions [1][2]. Due to the way
``empty_zero_page'' is declared in arch/sparc/include/setup.h, this
causes a warning to trigger at compile time in the function mem_init(),
which is subsequently converted to an error. The ensuing patch fixes
this issue and aligns the declaration of empty_zero_page to that of
other architectures. Thank you.

Cheers,
Orlando.

[1] https://gcc.gnu.org/ml/gcc-patches/2016-10/msg02308.html
[2] https://gcc.gnu.org/gcc-7/changes.html

Signed-off-by: Orlando Arias 

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

osf_wait4(): fix infoleak

2017-05-25T12:30:17+00:00

commit a8c39544a6eb2093c04afd5005b6192bd0e880c6 upstream.

failing sys_wait4() won't fill struct rusage...

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

metag/uaccess: Check access_ok in strncpy_from_user

2017-05-25T12:30:16+00:00

commit 3a158a62da0673db918b53ac1440845a5b64fd90 upstream.

The metag implementation of strncpy_from_user() doesn't validate the src
pointer, which could allow reading of arbitrary kernel memory. Add a
short access_ok() check to prevent that.

Its still possible for it to read across the user/kernel boundary, but
it will invariably reach a NUL character after only 9 bytes, leaking
only a static kernel address being loaded into D0Re0 at the beginning of
__start, which is acceptable for the immediate fix.

Reported-by: Al Viro 
Signed-off-by: James Hogan 
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

metag/uaccess: Fix access_ok()

2017-05-25T12:30:16+00:00

commit 8a8b56638bcac4e64cccc88bf95a0f9f4b19a2fb upstream.

The __user_bad() macro used by access_ok() has a few corner cases
noticed by Al Viro where it doesn't behave correctly:

 - The kernel range check has off by 1 errors which permit access to the
   first and last byte of the kernel mapped range.

 - The kernel range check ends at LINCORE_BASE rather than
   META_MEMORY_LIMIT, which is ineffective when the kernel is in global
   space (an extremely uncommon configuration).

There are a couple of other shortcomings here too:

 - Access to the whole of the other address space is permitted (i.e. the
   global half of the address space when the kernel is in local space).
   This isn't ideal as it could theoretically still contain privileged
   mappings set up by the bootloader.

 - The size argument is unused, permitting user copies which start on
   valid pages at the end of the user address range and cross the
   boundary into the kernel address space (e.g. addr = 0x3ffffff0, size
   > 0x10).

It isn't very convenient to add size checks when disallowing certain
regions, and it seems far safer to be sure and explicit about what
userland is able to access, so invert the logic to allow certain regions
instead, and fix the off by 1 errors and missing size checks. This also
allows the get_fs() == KERNEL_DS check to be more easily optimised into
the user address range case.

We now have 3 such allowed regions:

 - The user address range (incorporating the get_fs() == KERNEL_DS
   check).

 - NULL (some kernel code expects this to work, and we'll always catch
   the fault anyway).

 - The core code memory region.

Fixes: 373cd784d0fc ("metag: Memory handling")
Reported-by: Al Viro 
Signed-off-by: James Hogan 
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

arm64: uaccess: ensure extension of access_ok() addr

2017-05-25T12:30:15+00:00

commit a06040d7a791a9177581dcf7293941bd92400856 upstream.

Our access_ok() simply hands its arguments over to __range_ok(), which
implicitly assummes that the addr parameter is 64 bits wide. This isn't
necessarily true for compat code, which might pass down a 32-bit address
parameter.

In these cases, we don't have a guarantee that the address has been zero
extended to 64 bits, and the upper bits of the register may contain
unknown values, potentially resulting in a suprious failure.

Avoid this by explicitly casting the addr parameter to an unsigned long
(as is done on other architectures), ensuring that the parameter is
widened appropriately.

Fixes: 0aea86a2176c ("arm64: User access library functions")
Acked-by: Will Deacon 
Signed-off-by: Mark Rutland 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

arm64: xchg: hazard against entire exchange variable

2017-05-25T12:30:15+00:00

commit fee960bed5e857eb126c4e56dd9ff85938356579 upstream.

The inline assembly in __XCHG_CASE() uses a +Q constraint to hazard
against other accesses to the memory location being exchanged. However,
the pointer passed to the constraint is a u8 pointer, and thus the
hazard only applies to the first byte of the location.

GCC can take advantage of this, assuming that other portions of the
location are unchanged, as demonstrated with the following test case:

union u {
	unsigned long l;
	unsigned int i[2];
};

unsigned long update_char_hazard(union u *u)
{
	unsigned int a, b;

	a = u->i[1];
	asm ("str %1, %0" : "+Q" (*(char *)&u->l) : "r" (0UL));
	b = u->i[1];

	return a ^ b;
}

unsigned long update_long_hazard(union u *u)
{
	unsigned int a, b;

	a = u->i[1];
	asm ("str %1, %0" : "+Q" (*(long *)&u->l) : "r" (0UL));
	b = u->i[1];

	return a ^ b;
}

The linaro 15.08 GCC 5.1.1 toolchain compiles the above as follows when
using -O2 or above:

0000000000000000 :
   0:	d2800001 	mov	x1, #0x0                   	// #0
   4:	f9000001 	str	x1, [x0]
   8:	d2800000 	mov	x0, #0x0                   	// #0
   c:	d65f03c0 	ret

0000000000000010 :
  10:	b9400401 	ldr	w1, [x0,#4]
  14:	d2800002 	mov	x2, #0x0                   	// #0
  18:	f9000002 	str	x2, [x0]
  1c:	b9400400 	ldr	w0, [x0,#4]
  20:	4a000020 	eor	w0, w1, w0
  24:	d65f03c0 	ret

This patch fixes the issue by passing an unsigned long pointer into the
+Q constraint, as we do for our cmpxchg code. This may hazard against
more than is necessary, but this is better than missing a necessary
hazard.

Fixes: 305d454aaa29 ("arm64: atomics: implement native {relaxed, acquire, release} atomics")
Acked-by: Will Deacon 
Signed-off-by: Mark Rutland 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

ARM: dts: at91: sama5d3_xplained: not all ADC channels are available

2017-05-25T12:30:15+00:00

commit d3df1ec06353e51fc44563d2e7e18d42811af290 upstream.

Remove ADC channels that are not available by default on the sama5d3_xplained
board (resistor not populated) in order to not create confusion.

Signed-off-by: Ludovic Desroches 
Acked-by: Nicolas Ferre 
Signed-off-by: Alexandre Belloni 
Signed-off-by: Greg Kroah-Hartman

ARM: dts: at91: sama5d3_xplained: fix ADC vref

2017-05-25T12:30:15+00:00

commit 9cdd31e5913c1f86dce7e201b086155b3f24896b upstream.

The voltage reference for the ADC is not 3V but 3.3V since it is connected to
VDDANA.

Signed-off-by: Ludovic Desroches 
Acked-by: Nicolas Ferre 
Signed-off-by: Alexandre Belloni 
Signed-off-by: Greg Kroah-Hartman

powerpc/64e: Fix hang when debugging programs with relocated kernel

2017-05-25T12:30:15+00:00

commit fd615f69a18a9d4aa5ef02a1dc83f319f75da8e7 upstream.

Debug interrupts can be taken during interrupt entry, since interrupt
entry does not automatically turn them off.  The kernel will check
whether the faulting instruction is between [interrupt_base_book3e,
__end_interrupts], and if so clear MSR[DE] and return.

However, when the kernel is built with CONFIG_RELOCATABLE, it can't use
LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e) and
LOAD_REG_IMMEDIATE(r15,__end_interrupts), as they ignore relocation.
Thus, if the kernel is actually running at a different address than it
was built at, the address comparison will fail, and the exception entry
code will hang at kernel_dbg_exc.

r2(toc) is also not usable here, as r2 still holds data from the
interrupted context, so LOAD_REG_ADDR() doesn't work either.  So we use
the *name@got* to get the EV of two labels directly.

Test programs test.c shows as follows:
int main(int argc, char *argv[])
{
	if (access("/proc/sys/kernel/perf_event_paranoid", F_OK) == -1)
		printf("Kernel doesn't have perf_event support\n");
}

Steps to reproduce the bug, for example:
 1) ./gdb ./test
 2) (gdb) b access
 3) (gdb) r
 4) (gdb) s

Signed-off-by: Liu Hailong 
Signed-off-by: Jiang Xuexin 
Reviewed-by: Jiang Biao 
Reviewed-by: Liu Song 
Reviewed-by: Huang Jian 
[scottwood: cleaned up commit message, and specified bad behavior
 as a hang rather than an oops to correspond to mainline kernel behavior]
Fixes: 1cb6e0649248 ("powerpc/book3e: support CONFIG_RELOCATABLE")
Signed-off-by: Scott Wood 
Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Fix of_node_put() underflow during DLPAR remove

2017-05-25T12:30:15+00:00

commit 68baf692c435339e6295cb470ea5545cbc28160e upstream.

Historically struct device_node references were tracked using a kref embedded as
a struct field. Commit 75b57ecf9d1d ("of: Make device nodes kobjects so they
show up in sysfs") (Mar 2014) refactored device_nodes to be kobjects such that
the device tree could by more simply exposed to userspace using sysfs.

Commit 0829f6d1f69e ("of: device_node kobject lifecycle fixes") (Mar 2014)
followed up these changes to better control the kobject lifecycle and in
particular the referecne counting via of_node_get(), of_node_put(), and
of_node_init().

A result of this second commit was that it introduced an of_node_put() call when
a dynamic node is detached, in of_node_remove(), that removes the initial kobj
reference created by of_node_init().

Traditionally as the original dynamic device node user the pseries code had
assumed responsibilty for releasing this final reference in its platform
specific DLPAR detach code.

This patch fixes a refcount underflow introduced by commit 0829f6d1f6, and
recently exposed by the upstreaming of the recount API.

Messages like the following are no longer seen in the kernel log with this
patch following DLPAR remove operations of cpus and pci devices.

  rpadlpar_io: slot PHB 72 removed
  refcount_t: underflow; use-after-free.
  ------------[ cut here ]------------
  WARNING: CPU: 5 PID: 3335 at lib/refcount.c:128 refcount_sub_and_test+0xf4/0x110

Fixes: 0829f6d1f69e ("of: device_node kobject lifecycle fixes")
Signed-off-by: Tyrel Datwyler 
[mpe: Make change log commit references more verbose]
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman