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? Willy and Kees: I left the config option alone. The -tiny people will like it, and we can always add a sysctl of some sort later. Changes from v3: - Hopefully fixed Xen. - Fixed 32-bit test case on 32-bit native kernel. - Fix bogus vumnap for some LDT sizes. - Strengthen test case to check all LDT sizes (catches bogus vunmap). - Lots of cleanups, mostly from Borislav. - Simplify IPI code using on_each_cpu_mask. 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 | 262 +++++++++--------- 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(+), 155 deletions(-) create mode 100644 tools/testing/selftests/x86/ldt_gdt.c -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
