linux-stable.git/arch/sh, branch v3.2.94 Linux kernel stable tree mm: larger stack guard gap, between vmas 2017-07-02T16:12:47+00:00 Hugh Dickins hughd@google.com 2017-06-19T18:32:47+00:00 640c7dfdc7c723143b1ce42f5569ec8565cbbde7 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 <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [Hugh Dickins: Backported to 3.2] [bwh: Fix more instances of vma->vm_start in sparc64 impl. of arch_get_unmapped_area_topdown() and generic impl. of hugetlb_get_unmapped_area()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
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 <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Hugh Dickins: Backported to 3.2]
[bwh: Fix more instances of vma->vm_start in sparc64 impl. of
 arch_get_unmapped_area_topdown() and generic impl. of
 hugetlb_get_unmapped_area()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sh: fix copy_from_user() 2016-11-20T01:01:40+00:00 Al Viro viro@zeniv.linux.org.uk 2016-08-22T03:39:47+00:00 6089b5ee9c5f2de2bae342da15afe8d4124b9ebe commit 6e050503a150b2126620c1a1e9b3a368fcd51eac upstream. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 6e050503a150b2126620c1a1e9b3a368fcd51eac upstream.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sh64: failing __get_user() should zero 2016-11-20T01:01:40+00:00 Al Viro viro@zeniv.linux.org.uk 2016-08-22T03:33:47+00:00 264a03512d38ad22ba58ba06817f46506246309e commit c6852389228df9fb3067f94f3b651de2a7921b36 upstream. It could be done in exception-handling bits in __get_user_b() et.al., but the surgery involved would take more knowledge of sh64 details than I have or _want_ to have. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit c6852389228df9fb3067f94f3b651de2a7921b36 upstream.

It could be done in exception-handling bits in __get_user_b() et.al.,
but the surgery involved would take more knowledge of sh64 details
than I have or _want_ to have.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sh64: fix __NR_fgetxattr 2015-12-30T02:26:01+00:00 Dmitry V. Levin ldv@altlinux.org 2015-12-11T21:41:06+00:00 3953ba754ad4e00a58fbc20a9498c999ffe82f61 commit 2d33fa1059da4c8e816627a688d950b613ec0474 upstream. According to arch/sh/kernel/syscalls_64.S and common sense, __NR_fgetxattr has to be defined to 259, but it doesn't. Instead, it's defined to 269, which is of course used by another syscall, __NR_sched_setaffinity in this case. This bug was found by strace test suite. Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 2d33fa1059da4c8e816627a688d950b613ec0474 upstream.

According to arch/sh/kernel/syscalls_64.S and common sense, __NR_fgetxattr
has to be defined to 259, but it doesn't.  Instead, it's defined to 269,
which is of course used by another syscall, __NR_sched_setaffinity in this
case.

This bug was found by strace test suite.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
vm: add VM_FAULT_SIGSEGV handling support 2015-02-20T00:49:40+00:00 Linus Torvalds torvalds@linux-foundation.org 2015-01-29T18:51:32+00:00 219a047eb9a3cde86b5a341f9f8d4f6cf7e8cd56 commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream. The core VM already knows about VM_FAULT_SIGBUS, but cannot return a "you should SIGSEGV" error, because the SIGSEGV case was generally handled by the caller - usually the architecture fault handler. That results in lots of duplication - all the architecture fault handlers end up doing very similar "look up vma, check permissions, do retries etc" - but it generally works. However, there are cases where the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV. In particular, when accessing the stack guard page, libsigsegv expects a SIGSEGV. And it usually got one, because the stack growth is handled by that duplicated architecture fault handler. However, when the generic VM layer started propagating the error return from the stack expansion in commit fee7e49d4514 ("mm: propagate error from stack expansion even for guard page"), that now exposed the existing VM_FAULT_SIGBUS result to user space. And user space really expected SIGSEGV, not SIGBUS. To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those duplicate architecture fault handlers about it. They all already have the code to handle SIGSEGV, so it's about just tying that new return value to the existing code, but it's all a bit annoying. This is the mindless minimal patch to do this. A more extensive patch would be to try to gather up the mostly shared fault handling logic into one generic helper routine, and long-term we really should do that cleanup. Just from this patch, you can generally see that most architectures just copied (directly or indirectly) the old x86 way of doing things, but in the meantime that original x86 model has been improved to hold the VM semaphore for shorter times etc and to handle VM_FAULT_RETRY and other "newer" things, so it would be a good idea to bring all those improvements to the generic case and teach other architectures about them too. Reported-and-tested-by: Takashi Iwai <tiwai@suse.de> Tested-by: Jan Engelhardt <jengelh@inai.de> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots" Cc: linux-arch@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [bwh: Backported to 3.2: - Adjust filenames, context - Drop arc, metag, nios2 and lustre changes - For sh, patch both 32-bit and 64-bit implementations to use goto bad_area - For s390, pass int_code and trans_exc_code as arguments to do_no_context() and do_sigsegv()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream.

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Jan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
 - Adjust filenames, context
 - Drop arc, metag, nios2 and lustre changes
 - For sh, patch both 32-bit and 64-bit implementations to use goto bad_area
 - For s390, pass int_code and trans_exc_code as arguments to do_no_context()
   and do_sigsegv()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sh: fix format string bug in stack tracer 2014-04-30T15:23:25+00:00 Matt Fleming matt.fleming@intel.com 2014-04-03T21:46:20+00:00 75c623aeed530e1da2a97dfbfaef86b55121e00f commit a0c32761e73c9999cbf592b702f284221fea8040 upstream. Kees reported the following error: arch/sh/kernel/dumpstack.c: In function 'print_trace_address': arch/sh/kernel/dumpstack.c:118:2: error: format not a string literal and no format arguments [-Werror=format-security] Use the "%s" format so that it's impossible to interpret 'data' as a format string. Signed-off-by: Matt Fleming <matt.fleming@intel.com> Reported-by: Kees Cook <keescook@chromium.org> Acked-by: Kees Cook <keescook@chromium.org> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a0c32761e73c9999cbf592b702f284221fea8040 upstream.

Kees reported the following error:

   arch/sh/kernel/dumpstack.c: In function 'print_trace_address':
   arch/sh/kernel/dumpstack.c:118:2: error: format not a string literal and no format arguments [-Werror=format-security]

Use the "%s" format so that it's impossible to interpret 'data' as a
format string.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Reported-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sh: always link in helper functions extracted from libgcc 2014-02-15T19:20:12+00:00 Geert Uytterhoeven geert@linux-m68k.org 2013-12-19T01:08:48+00:00 bed3dd5996d716ae26a3974cbfca6153fb8556b8 commit 84ed8a99058e61567f495cc43118344261641c5f upstream. E.g. landisk_defconfig, which has CONFIG_NTFS_FS=m: ERROR: "__ashrdi3" [fs/ntfs/ntfs.ko] undefined! For "lib-y", if no symbols in a compilation unit are referenced by other units, the compilation unit will not be included in vmlinux. This breaks modules that do reference those symbols. Use "obj-y" instead to fix this. http://kisskb.ellerman.id.au/kisskb/buildresult/8838077/ This doesn't fix all cases. There are others, e.g. udivsi3. This is also not limited to sh, many architectures handle this in the same way. A simple solution is to unconditionally include all helper functions. A more complex solution is to make the choice of "lib-y" or "obj-y" depend on CONFIG_MODULES: obj-$(CONFIG_MODULES) += ... lib-y($CONFIG_MODULES) += ... Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Paul Mundt <lethal@linux-sh.org> Tested-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com> Reviewed-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 84ed8a99058e61567f495cc43118344261641c5f upstream.

E.g. landisk_defconfig, which has CONFIG_NTFS_FS=m:

  ERROR: "__ashrdi3" [fs/ntfs/ntfs.ko] undefined!

For "lib-y", if no symbols in a compilation unit are referenced by other
units, the compilation unit will not be included in vmlinux.  This
breaks modules that do reference those symbols.

Use "obj-y" instead to fix this.

http://kisskb.ellerman.id.au/kisskb/buildresult/8838077/

This doesn't fix all cases. There are others, e.g. udivsi3.
This is also not limited to sh, many architectures handle this in the
same way.

A simple solution is to unconditionally include all helper functions.
A more complex solution is to make the choice of "lib-y" or "obj-y" depend
on CONFIG_MODULES:

  obj-$(CONFIG_MODULES) += ...
  lib-y($CONFIG_MODULES) += ...

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Tested-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sh: Fix FDPIC binary loader 2013-02-06T04:33:29+00:00 Thomas Schwinge thomas@codesourcery.com 2012-11-16T09:46:20+00:00 389a31cde3d4b488b605ec1d6eda187001fb1fbe commit 4a71997a3279a339e7336ea5d0cd27282e2dea44 upstream. Ensure that the aux table is properly initialized, even when optional features are missing. Without this, the FDPIC loader did not work. This was meant to be included in commit d5ab780305bb6d60a7b5a74f18cf84eb6ad153b1. Signed-off-by: Thomas Schwinge <thomas@codesourcery.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 4a71997a3279a339e7336ea5d0cd27282e2dea44 upstream.

Ensure that the aux table is properly initialized, even when optional features
are missing.  Without this, the FDPIC loader did not work.  This was meant to
be included in commit d5ab780305bb6d60a7b5a74f18cf84eb6ad153b1.

Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
oprofile, arm/sh: Fix oprofile_arch_exit() linkage issue 2011-12-23T10:58:34+00:00 Vladimir Zapolskiy vladimir.zapolskiy@nokia.com 2011-12-22T15:15:40+00:00 55205c916e179e09773d98d290334d319f45ac6b This change fixes a linking problem, which happens if oprofile is selected to be compiled as built-in: `oprofile_arch_exit' referenced in section `.init.text' of arch/arm/oprofile/built-in.o: defined in discarded section `.exit.text' of arch/arm/oprofile/built-in.o The problem is appeared after commit 87121ca504, which introduced oprofile_arch_exit() calls from __init function. Note that the aforementioned commit has been backported to stable branches, and the problem is known to be reproduced at least with 3.0.13 and 3.1.5 kernels. Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@nokia.com> Signed-off-by: Robert Richter <robert.richter@amd.com> Cc: Will Deacon <will.deacon@arm.com> Cc: oprofile-list <oprofile-list@lists.sourceforge.net> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/20111222151540.GB16765@erda.amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu> 
This change fixes a linking problem, which happens if oprofile
is selected to be compiled as built-in:

  `oprofile_arch_exit' referenced in section `.init.text' of
  arch/arm/oprofile/built-in.o: defined in discarded section
  `.exit.text' of arch/arm/oprofile/built-in.o

The problem is appeared after commit 87121ca504, which
introduced oprofile_arch_exit() calls from __init function. Note
that the aforementioned commit has been backported to stable
branches, and the problem is known to be reproduced at least
with 3.0.13 and 3.1.5 kernels.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@nokia.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20111222151540.GB16765@erda.amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
sh: fix build warning in board-sh7757lcr 2011-11-18T07:45:50+00:00 Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com 2011-11-18T07:32:34+00:00 19d7ca2998e095086869318dd2ad966952f5ac82 This patch fixed the following build warnings: CC arch/sh/boards/board-sh7757lcr.o arch/sh/boards/board-sh7757lcr.c:77: warning: initialization from incompatible pointer type arch/sh/boards/board-sh7757lcr.c:106: warning: initialization from incompatible pointer type arch/sh/boards/board-sh7757lcr.c:151: warning: initialization from incompatible pointer type arch/sh/boards/board-sh7757lcr.c:181: warning: initialization from incompatible pointer type arch/sh/boards/board-sh7757lcr.c:213: warning: missing braces around initializer arch/sh/boards/board-sh7757lcr.c:213: warning: (near initialization for ‘sh7757lcr_mmcif_dma.chan_priv_tx’) Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org> 
This patch fixed the following build warnings:

  CC      arch/sh/boards/board-sh7757lcr.o
arch/sh/boards/board-sh7757lcr.c:77: warning: initialization from incompatible pointer type
arch/sh/boards/board-sh7757lcr.c:106: warning: initialization from incompatible pointer type
arch/sh/boards/board-sh7757lcr.c:151: warning: initialization from incompatible pointer type
arch/sh/boards/board-sh7757lcr.c:181: warning: initialization from incompatible pointer type
arch/sh/boards/board-sh7757lcr.c:213: warning: missing braces around initializer
arch/sh/boards/board-sh7757lcr.c:213: warning: (near initialization for ‘sh7757lcr_mmcif_dma.chan_priv_tx’)

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>