linux-stable.git/arch/metag/include, branch linux-4.4.y Linux kernel stable tree metag/uaccess: Check access_ok in strncpy_from_user 2017-05-25T12:30:16+00:00 James Hogan james.hogan@imgtec.com 2017-05-02T18:41:06+00:00 ca19dd15e7bb29ed8fc0d531af96df37a4988737 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 <viro@zeniv.linux.org.uk> Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <viro@zeniv.linux.org.uk>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
metag/uaccess: Fix access_ok() 2017-05-25T12:30:16+00:00 James Hogan james.hogan@imgtec.com 2017-04-28T09:50:26+00:00 2d9b2e7808325ea8f534041a8affb44c461406fd 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 <viro@zeniv.linux.org.uk> Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <viro@zeniv.linux.org.uk>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
metag/usercopy: Zero rest of buffer from copy_from_user 2017-04-12T10:38:34+00:00 James Hogan james.hogan@imgtec.com 2017-03-31T10:14:02+00:00 29b5eb517c6961ea9e9b16c49b5cf7fd93860be2 commit 563ddc1076109f2b3f88e6d355eab7b6fd4662cb upstream. Currently we try to zero the destination for a failed read from userland in fixup code in the usercopy.c macros. The rest of the destination buffer is then zeroed from __copy_user_zeroing(), which is used for both copy_from_user() and __copy_from_user(). Unfortunately we fail to zero in the fixup code as D1Ar1 is set to 0 before the fixup code entry labels, and __copy_from_user() shouldn't even be zeroing the rest of the buffer. Move the zeroing out into copy_from_user() and rename __copy_user_zeroing() to raw_copy_from_user() since it no longer does any zeroing. This also conveniently matches the name needed for RAW_COPY_USER support in a later patch. Fixes: 373cd784d0fc ("metag: Memory handling") Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 563ddc1076109f2b3f88e6d355eab7b6fd4662cb upstream.

Currently we try to zero the destination for a failed read from userland
in fixup code in the usercopy.c macros. The rest of the destination
buffer is then zeroed from __copy_user_zeroing(), which is used for both
copy_from_user() and __copy_from_user().

Unfortunately we fail to zero in the fixup code as D1Ar1 is set to 0
before the fixup code entry labels, and __copy_from_user() shouldn't even
be zeroing the rest of the buffer.

Move the zeroing out into copy_from_user() and rename
__copy_user_zeroing() to raw_copy_from_user() since it no longer does
any zeroing. This also conveniently matches the name needed for
RAW_COPY_USER support in a later patch.

Fixes: 373cd784d0fc ("metag: Memory handling")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
metag: Only define atomic_dec_if_positive conditionally 2016-10-28T07:01:31+00:00 Guenter Roeck linux@roeck-us.net 2016-10-07T17:40:59+00:00 c8f0fef21d6426a08aa262073bc41f3c7512f651 commit 35d04077ad96ed33ceea2501f5a4f1eacda77218 upstream. The definition of atomic_dec_if_positive() assumes that atomic_sub_if_positive() exists, which is only the case if metag specific atomics are used. This results in the following build error when trying to build metag1_defconfig. kernel/ucount.c: In function 'dec_ucount': kernel/ucount.c:211: error: implicit declaration of function 'atomic_sub_if_positive' Moving the definition of atomic_dec_if_positive() into the metag conditional code fixes the problem. Fixes: 6006c0d8ce94 ("metag: Atomics, locks and bitops") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 35d04077ad96ed33ceea2501f5a4f1eacda77218 upstream.

The definition of atomic_dec_if_positive() assumes that
atomic_sub_if_positive() exists, which is only the case if
metag specific atomics are used. This results in the following
build error when trying to build metag1_defconfig.

kernel/ucount.c: In function 'dec_ucount':
kernel/ucount.c:211: error:
	implicit declaration of function 'atomic_sub_if_positive'

Moving the definition of atomic_dec_if_positive() into the metag
conditional code fixes the problem.

Fixes: 6006c0d8ce94 ("metag: Atomics, locks and bitops")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
metag: copy_from_user() should zero the destination on access_ok() failure 2016-09-24T08:07:45+00:00 Al Viro viro@zeniv.linux.org.uk 2016-08-19T02:08:20+00:00 312357440573be806fcaf4b2fb0c36078476ec30 commit 8ae95ed4ae5fc7c3391ed668b2014c9e2079533b upstream. Acked-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8ae95ed4ae5fc7c3391ed668b2014c9e2079533b upstream.

Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
metag: Fix atomic_*_return inline asm constraints 2016-09-15T06:27:54+00:00 James Hogan james.hogan@imgtec.com 2016-05-03T08:11:21+00:00 73e6305cf0f89ee66abe522a75eb614212b1c8a2 commit 096a8b6d5e7ab9f8ca3d2474b3ca6a1fe79e0371 upstream. The argument i of atomic_*_return() operations is given to inline asm with the "bd" constraint, which means "An Op2 register where Op1 is a data unit register and the instruction supports O2R", however Op1 is constrained by "da" which allows an address unit register to be used. Fix the constraint to use "br", meaning "An Op2 register and the instruction supports O2R", i.e. not requiring Op1 to be a data unit register. Fixes: d6dfe2509da9 ("locking,arch,metag: Fold atomic_ops") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 096a8b6d5e7ab9f8ca3d2474b3ca6a1fe79e0371 upstream.

The argument i of atomic_*_return() operations is given to inline asm
with the "bd" constraint, which means "An Op2 register where Op1 is a
data unit register and the instruction supports O2R", however Op1 is
constrained by "da" which allows an address unit register to be used.

Fix the constraint to use "br", meaning "An Op2 register and the
instruction supports O2R", i.e. not requiring Op1 to be a data unit
register.

Fixes: d6dfe2509da9 ("locking,arch,metag: Fold atomic_ops")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
metag: Fix __cmpxchg_u32 asm constraint for CMP 2016-08-20T16:09:23+00:00 James Hogan james.hogan@imgtec.com 2016-08-04T16:36:08+00:00 8660eadce2bafd16b2b2d0100190c5ac76519caf commit 6154c187b97ee7513046bb4eb317a89f738f13ef upstream. The LNKGET based atomic sequence in __cmpxchg_u32 has slightly incorrect constraints for the return value which under certain circumstances can allow an address unit register to be used as the first operand of a CMP instruction. This isn't a valid instruction however as the encodings only allow a data unit to be specified. This would result in an assembler error like the following: Error: failed to assemble instruction: "CMP A0.2,D0Ar6" Fix by changing the constraint from "=&da" (assigned, early clobbered, data or address unit register) to "=&d" (data unit register only). The constraint for the second operand, "bd" (an op2 register where op1 is a data unit register and the instruction supports O2R) is already correct assuming the first operand is a data unit register. Other cases of CMP in inline asm have had their constraints checked, and appear to all be fine. Fixes: 6006c0d8ce94 ("metag: Atomics, locks and bitops") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: linux-metag@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6154c187b97ee7513046bb4eb317a89f738f13ef upstream.

The LNKGET based atomic sequence in __cmpxchg_u32 has slightly incorrect
constraints for the return value which under certain circumstances can
allow an address unit register to be used as the first operand of a CMP
instruction. This isn't a valid instruction however as the encodings
only allow a data unit to be specified. This would result in an
assembler error like the following:

  Error: failed to assemble instruction: "CMP A0.2,D0Ar6"

Fix by changing the constraint from "=&da" (assigned, early clobbered,
data or address unit register) to "=&d" (data unit register only).

The constraint for the second operand, "bd" (an op2 register where op1
is a data unit register and the instruction supports O2R) is already
correct assuming the first operand is a data unit register.

Other cases of CMP in inline asm have had their constraints checked, and
appear to all be fine.

Fixes: 6006c0d8ce94 ("metag: Atomics, locks and bitops")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag 'metag-for-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag 2015-11-11T00:24:25+00:00 Linus Torvalds torvalds@linux-foundation.org 2015-11-11T00:24:25+00:00 c6de7f1754bd474019c60d6f076fa3f704e46b78 Pull metag arch updates from James Hogan: "A fix for 4KiB stacks with SMP, and a change of maintenance status to 'Odd Fixes'" * tag 'metag-for-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag: MAINTAINERS: Change Meta arch port status to Odd Fixes metag: Turn irq_ctx_* macros into static inlines metag: SMP: Fix 4KiB stack setup on secondary CPUs 
Pull metag arch updates from James Hogan:
 "A fix for 4KiB stacks with SMP, and a change of maintenance status to
  'Odd Fixes'"

* tag 'metag-for-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag:
  MAINTAINERS: Change Meta arch port status to Odd Fixes
  metag: Turn irq_ctx_* macros into static inlines
  metag: SMP: Fix 4KiB stack setup on secondary CPUs
kmap_atomic_to_page() has no users, remove it 2015-11-09T23:11:24+00:00 Nicolas Pitre nicolas.pitre@linaro.org 2015-11-09T22:58:23+00:00 77c5b5da02f0a30d61144a546c4ef3657e3b817d Removal started in commit 5bbeed12bdc3 ("sparc32: drop unused kmap_atomic_to_page"). Let's do it across the whole tree. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Removal started in commit 5bbeed12bdc3 ("sparc32: drop unused
kmap_atomic_to_page").  Let's do it across the whole tree.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge tag 'v4.3-rc4' into locking/core, to pick up fixes before applying new changes 2015-10-06T15:10:28+00:00 Ingo Molnar mingo@kernel.org 2015-10-06T15:10:28+00:00 82fc167c392a1700f9adbde639730ee8c8122474 Signed-off-by: Ingo Molnar <mingo@kernel.org> 
Signed-off-by: Ingo Molnar <mingo@kernel.org>