lkml.org 
[lkml]   [2015]   [Jul]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v3 0/3] x86: modify_ldt improvement, test, and config option
Date
Here's v3.  It fixes the "dazed and confused" issue, I hope.  It's also
probably a good general attack surface reduction, and it replaces some
scary code with IMO less scary code.

Also, servers and embedded systems should probably turn off modify_ldt.
This makes that possible.

Xen people, can you take a look at this?

Changes from v2:
- Allocate ldt_struct and the LDT entries separately. This should fix Xen.
- Stop using write_ldt_entry, since I'm pretty sure it's unnecessary now
that we no longer mutate an in-use LDT. (Xen people, can you check?)

Changes from v1:
- The config option is new.
- The test case is new.
- Fixed a missing allocation failure check.
- Fixed a use-after-free on fork().

Andy Lutomirski (3):
x86/ldt: Make modify_ldt synchronous
x86/ldt: Make modify_ldt optional
selftests/x86, x86/ldt: Add a selftest for modify_ldt

arch/x86/Kconfig | 17 ++
arch/x86/include/asm/desc.h | 15 --
arch/x86/include/asm/mmu.h | 5 +-
arch/x86/include/asm/mmu_context.h | 68 ++++-
arch/x86/kernel/Makefile | 3 +-
arch/x86/kernel/cpu/common.c | 4 +-
arch/x86/kernel/cpu/perf_event.c | 16 +-
arch/x86/kernel/ldt.c | 258 ++++++++++--------
arch/x86/kernel/process_64.c | 6 +-
arch/x86/kernel/step.c | 8 +-
arch/x86/power/cpu.c | 3 +-
kernel/sys_ni.c | 1 +
tools/testing/selftests/x86/Makefile | 2 +-
tools/testing/selftests/x86/ldt_gdt.c | 492 ++++++++++++++++++++++++++++++++++
14 files changed, 747 insertions(+), 151 deletions(-)
create mode 100644 tools/testing/selftests/x86/ldt_gdt.c

--
2.4.3



\
 
 \ /
  Last update: 2015-07-22 21:41    [W:0.163 / U:0.220 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site