linux/arch/x86/um
Andy Lutomirski f56141e3e2 all arches, signal: move restart_block to struct task_struct
If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12 18:54:12 -08:00
..
asm arch: Add lightweight memory barriers dma_rmb() and dma_wmb() 2014-12-11 21:15:06 -05:00
os-Linux um: prctl: Do not include linux/ptrace.h 2013-09-07 10:57:11 +02:00
shared/sysdep sanitize rt_sigaction() situation a bit 2013-02-03 15:09:18 -05:00
vdso x86, vdso: Clean up 32-bit vs 64-bit vdso params 2014-05-05 13:18:40 -07:00
bug.c
bugs_32.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
bugs_64.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
checksum_32.S um: remove csum_partial_copy_generic_i386 to clean up exception table 2014-10-13 17:15:02 +02:00
delay.c
elfcore.c switch elf_core_write_extra_data() to dump_emit() 2013-11-09 00:16:23 -05:00
fault.c um: don't compare a pointer to 0 2012-12-20 11:49:39 -08:00
Kconfig arch/um: make it work with defconfig and x86_64 2013-11-17 11:31:48 +01:00
ksyms.c
ldt.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
Makefile x86: switch to generic old sigaction 2013-02-03 18:16:27 -05:00
mem_32.c coredump: remove VM_ALWAYSDUMP flag 2012-03-23 16:58:42 -07:00
mem_64.c arm64,ia64,ppc,s390,sh,tile,um,x86,mm: remove default gate area 2014-08-08 15:57:27 -07:00
ptrace_32.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
ptrace_64.c
ptrace_user.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
setjmp_32.S
setjmp_64.S
signal.c all arches, signal: move restart_block to struct task_struct 2015-02-12 18:54:12 -08:00
stub_32.S um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
stub_64.S um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
stub_segv.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
sys_call_table_32.c x86, um: actually mark system call tables readonly 2015-01-04 14:21:25 +01:00
sys_call_table_64.c x86, um: actually mark system call tables readonly 2015-01-04 14:21:25 +01:00
syscalls_64.c um: kill thread->forking 2012-09-27 18:04:55 +02:00
sysrq_32.c um: Rewrite show_stack() 2013-11-17 11:27:25 +01:00
sysrq_64.c um: Rewrite show_stack() 2013-11-17 11:27:25 +01:00
tls_32.c make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect 2013-03-03 22:58:33 -05:00
tls_64.c um: get rid of pointless include "..." where include <...> will do 2012-10-09 22:28:45 +02:00
user-offsets.c x32: Add x32 system calls to syscall/syscall_64.tbl 2012-02-20 12:48:49 -08:00