linux-stable.git/arch, branch v4.4.31

kvm: x86: Check memopp before dereference (CVE-2016-8630)

2016-11-10T15:36:37+00:00

commit d9092f52d7e61dd1557f2db2400ddb430e85937e upstream.

Commit 41061cdb98 ("KVM: emulate: do not initialize memopp") removes a
check for non-NULL under incorrect assumptions. An undefined instruction
with a ModR/M byte with Mod=0 and R/M-5 (e.g. 0xc7 0x15) will attempt
to dereference a null pointer here.

Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5
Message-Id: <1477592752-126650-2-git-send-email-osh@google.com>
Signed-off-by: Owen Hofmann 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

ARM: 8584/1: floppy: avoid gcc-6 warning

2016-11-10T15:36:36+00:00

commit dd665be0e243873343a28e18f9f345927b658daf upstream.

gcc-6.0 warns about comparisons between two identical expressions,
which is what we get in the floppy driver when writing to the FD_DOR
register:

drivers/block/floppy.c: In function 'set_dor':
drivers/block/floppy.c:810:44: error: self-comparison always evaluates to true [-Werror=tautological-compare]
   fd_outb(newdor, FD_DOR);

It would be nice to use a static inline function instead of the
macro, to avoid the warning, but we cannot do that because the
FD_DOR definition is incomplete at this point.

Adding a cast to (u32) is a harmless way to shut up the warning,
just not very nice.

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

powerpc/ptrace: Fix out of bounds array access warning

2016-11-10T15:36:36+00:00

commit 1e407ee3b21f981140491d5b8a36422979ca246f upstream.

gcc-6 correctly warns about a out of bounds access

arch/powerpc/kernel/ptrace.c:407:24: warning: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Warray-bounds]
        offsetof(struct thread_fp_state, fpr[32][0]));
                        ^

check the end of array instead of beginning of next element to fix this

Signed-off-by: Khem Raj 
Cc: Kees Cook 
Cc: Michael Ellerman 
Cc: Segher Boessenkool 
Tested-by: Aaro Koskinen 
Acked-by: Olof Johansson 
Signed-off-by: Michael Ellerman 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

x86/xen: fix upper bound of pmd loop in xen_cleanhighmap()

2016-11-10T15:36:36+00:00

commit 1cf38741308c64d08553602b3374fb39224eeb5a upstream.

xen_cleanhighmap() is operating on level2_kernel_pgt only. The upper
bound of the loop setting non-kernel-image entries to zero should not
exceed the size of level2_kernel_pgt.

Reported-by: Linus Torvalds 
Signed-off-by: Juergen Gross 
Signed-off-by: David Vrabel 
Signed-off-by: Greg Kroah-Hartman

parisc: Ensure consistent state when switching to kernel stack at syscall entry

2016-11-10T15:36:34+00:00

commit 6ed518328d0189e0fdf1bb7c73290d546143ea66 upstream.

We have one critical section in the syscall entry path in which we switch from
the userspace stack to kernel stack. In the event of an external interrupt, the
interrupt code distinguishes between those two states by analyzing the value of
sr7. If sr7 is zero, it uses the kernel stack. Therefore it's important, that
the value of sr7 is in sync with the currently enabled stack.

This patch now disables interrupts while executing the critical section.  This
prevents the interrupt handler to possibly see an inconsistent state which in
the worst case can lead to crashes.

Interestingly, in the syscall exit path interrupts were already disabled in the
critical section which switches back to the userspace stack.

Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

KVM: MIPS: Make ERET handle ERL before EXL

2016-11-10T15:36:34+00:00

commit ede5f3e7b54a4347be4d8525269eae50902bd7cd upstream.

The ERET instruction to return from exception is used for returning from
exception level (Status.EXL) and error level (Status.ERL). If both bits
are set however we should be returning from ERL first, as ERL can
interrupt EXL, for example when an NMI is taken. KVM however checks EXL
first.

Fix the order of the checks to match the pseudocode in the instruction
set manual.

Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan 
Cc: Paolo Bonzini 
Cc: "Radim Krčmář" 
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

KVM: x86: fix wbinvd_dirty_mask use-after-free

2016-11-10T15:36:34+00:00

commit bd768e146624cbec7122ed15dead8daa137d909d upstream.

vcpu->arch.wbinvd_dirty_mask may still be used after freeing it,
corrupting memory. For example, the following call trace may set a bit
in an already freed cpu mask:
    kvm_arch_vcpu_load
    vcpu_load
    vmx_free_vcpu_nested
    vmx_free_vcpu
    kvm_arch_vcpu_free

Fix this by deferring freeing of wbinvd_dirty_mask.

Signed-off-by: Ido Yariv 
Reviewed-by: Paolo Bonzini 
Signed-off-by: Radim Krčmář 
Signed-off-by: Greg Kroah-Hartman

Fix potential infoleak in older kernels

2016-11-10T15:36:34+00:00

Not upstream as it is not needed there.

So a patch something like this might be a safe way to fix the
potential infoleak in older kernels.

THIS IS UNTESTED. It's a very obvious patch, though, so if it compiles
it probably works. It just initializes the output variable with 0 in
the inline asm description, instead of doing it in the exception
handler.

It will generate slightly worse code (a few unnecessary ALU
operations), but it doesn't have any interactions with the exception
handler implementation.


Signed-off-by: Greg Kroah-Hartman

h8300: fix syscall restarting

2016-11-10T15:36:32+00:00

commit 21753583056d48a5fad964d6f272e28168426845 upstream.

Back in commit f56141e3e2d9 ("all arches, signal: move restart_block to
struct task_struct"), all architectures and core code were changed to
use task_struct::restart_block.  However, when h8300 support was
subsequently restored in v4.2, it was not updated to account for this,
and maintains thread_info::restart_block, which is not kept in sync.

This patch drops the redundant restart_block from thread_info, and moves
h8300 to the common one in task_struct, ensuring that syscall restarting
always works as expected.

Fixes: f56141e3e2d9 ("all arches, signal: move restart_block to struct task_struct")
Link: http://lkml.kernel.org/r/1476714934-11635-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Mark Rutland 
Cc: Andy Lutomirski 
Cc: Yoshinori Sato 
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Revert "fix minor infoleak in get_user_ex()"

2016-11-01T01:56:26+00:00

This reverts commit 9d25c78ec01c402dc56272693c44ef9d72ecdd2e which is
1c109fabbd51863475cd12ac206bdd249aee35af upstream

Cc: Al Viro 
Cc: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman