Currently we are not including randomized stack size when calculating
mmap_base address in arch_pick_mmap_layout for topdown case. This might
cause that mmap_base starts in the stack reserved area because stack is
randomized by 1GB for 64b (8MB for 32b) and the minimum gap is 128MB.
If the stack really grows down to mmap_base then we can get silent mmap
region overwrite by the stack values.
Let's include maximum stack randomization size into MIN_GAP which is
used as the low bound for the gap in mmap.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
LKML-Reference: <1252400515-6866-1-git-send-email-mhocko@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Stable Team <stable@kernel.org>
Impact: pt_regs changed, lazy gs handling made optional, add slight
overhead to SAVE_ALL, simplifies error_code path a bit
On x86_32, %gs hasn't been used by kernel and handled lazily. pt_regs
doesn't have place for it and gs is saved/loaded only when necessary.
In preparation for stack protector support, this patch makes lazy %gs
handling optional by doing the followings.
* Add CONFIG_X86_32_LAZY_GS and place for gs in pt_regs.
* Save and restore %gs along with other registers in entry_32.S unless
LAZY_GS. Note that this unfortunately adds "pushl $0" on SAVE_ALL
even when LAZY_GS. However, it adds no overhead to common exit path
and simplifies entry path with error code.
* Define different user_gs accessors depending on LAZY_GS and add
lazy_save_gs() and lazy_load_gs() which are noop if !LAZY_GS. The
lazy_*_gs() ops are used to save, load and clear %gs lazily.
* Define ELF_CORE_COPY_KERNEL_REGS() which always read %gs directly.
xen and lguest changes need to be verified.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
On x86_32, %gs is handled lazily. It's not saved and restored on
kernel entry/exit but only when necessary which usually is during task
switch but there are few other places. Currently, it's done by
calling savesegment() and loadsegment() explicitly. Define
get_user_gs(), set_user_gs() and task_user_gs() and use them instead.
While at it, clean up register access macros in signal.c.
This cleans up code a bit and will help future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch_setup_additional_pages currently gets two arguments, the binary
format descripton and an indication if the process uses an executable
stack or not. The second argument is not used by anybody, it could
be removed without replacement.
What actually does make sense is to pass an indication if the process
uses the elf interpreter or not. The glibc code will not use anything
from the vdso if the process does not use the dynamic linker, so for
statically linked binaries the architecture backend can choose not
to map the vdso.
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:
a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The SET_PERSONALITY macro is always called with a second argument of 0.
Remove the ibcs argument and the various tests to set the PER_SVR4
personality.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Use savesegment and loadsegment consistently in ia32 compat code.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.
The format:
1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
underscores.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
asm/elf.h, asm/page.h and asm/user.h don't export to userspace now, so we can
drop #ifdef __KERNEL__ for them.
[k.shutemov@gmail.com: remove #ifdef __KERNEL_]
Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com>
Reviewed-by: David Woodhouse <dwmw2@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kdump needs ELF_CORE_COPY_REGS in crash_save_cpu().
This lack of the macro causes the following BUG.
SysRq : Trigger a crashdump
------------[ cut here ]------------
kernel BUG at include/linux/elfcore.h:105!
invalid opcode: 0000 [1] PREEMPT SMP
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This switches x86-64's 32-bit ELF support to use the shared
fs/compat_binfmt_elf.c code instead of our own ia32_binfmt.c.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This removes a bunch of dead code that is no longer needed now
that the user_regset interfaces are being used for all these jobs.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This switches x86 to the user_regset-based code for ELF core dumps.
The core dumps come out exactly the same as before.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We have a lot of code which differs only by the naming of specific
members of structures that contain registers. In order to enable
additional unifications, this patch drops the e- or r- size prefix
from the register names in struct pt_regs, and drops the x- prefixes
for segment registers on the 32-bit side.
This patch also performs the equivalent renames in some additional
places that might be candidates for unification in the future.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This makes x86_64's ia32 emulation support share the sources used in the
32-bit kernel for the 32-bit vDSO and much of its setup code.
The 32-bit vDSO mapping now behaves the same on x86_64 as on native 32-bit.
The abi.syscall32 sysctl on x86_64 now takes the same values that
vm.vdso_enabled takes on the 32-bit kernel. That is, 1 means a randomized
vDSO location, 2 means the fixed old address. The CONFIG_COMPAT_VDSO
option is now available to make this the default setting, the same meaning
it has for the 32-bit kernel. (This does not affect the 64-bit vDSO.)
The argument vdso32=[012] can be used on both 32-bit and 64-bit kernels to
set this paramter at boot time. The vdso=[012] argument still does this
same thing on the 32-bit kernel.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This makes the i386 kernel use the new vDSO build in arch/x86/vdso/vdso32/
to replace the old one from arch/x86/kernel/.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Randomize the location of the heap (brk) for i386 and x86_64. The range is
randomized in the range starting at current brk location up to 0x02000000
offset for both architectures. This, together with
pie-executable-randomization.patch and
pie-executable-randomization-fix.patch, should make the address space
randomization on i386 and x86_64 complete.
Arjan says:
This is known to break older versions of some emacs variants, whose dumper
code assumed that the last variable declared in the program is equal to the
start of the dynamically allocated memory region.
(The dumper is the code where emacs effectively dumps core at the end of it's
compilation stage; this coredump is then loaded as the main program during
normal use)
iirc this was 5 years or so; we found this way back when I was at RH and we
first did the security stuff there (including this brk randomization). It
wasn't all variants of emacs, and it got fixed as a result (I vaguely remember
that emacs already had code to deal with it for other archs/oses, just
ifdeffed wrongly).
It's a rare and wrong assumption as a general thing, just on x86 it mostly
happened to be true (but to be honest, it'll break too if gcc does
something fancy or if the linker does a non-standard order). Still its
something we should at least document.
Note 2: afaik it only broke the emacs *build*. I'm not 100% sure about that
(it IS 5 years ago) though.
[ akpm@linux-foundation.org: deuglification ]
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Move the headers to include/asm-x86 and fixup the
header install make rules
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Michal Hocko