This is a note to let you know that I've just added the patch titled
selftests/x86: Add tests for the STR and SLDT instructions
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-x86-add-tests-for-the-str-and-sldt-instructions.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a9e017d5619eb371460c8e516f4684def62bef3a Mon Sep 17 00:00:00 2001
From: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
Date: Sun, 5 Nov 2017 18:27:57 -0800
Subject: selftests/x86: Add tests for the STR and SLDT instructions
From: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
commit a9e017d5619eb371460c8e516f4684def62bef3a upstream.
The STR and SLDT instructions are not valid when running on virtual-8086
mode and generate an invalid operand exception. These two instructions are
protected by the Intel User-Mode Instruction Prevention (UMIP) security
feature. In protected mode, if UMIP is enabled, these instructions generate
a general protection fault if called from CPL > 0. Linux traps the general
protection fault and emulates the instructions sgdt, sidt and smsw; but not
str and sldt.
These tests are added to verify that the emulation code does not emulate
these two instructions but the expected invalid operand exception is
seen.
Tests fallback to exit with INT3 in case emulation does happen.
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Chen Yucong <slaoub@xxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ravi V. Shankar <ravi.v.shankar@xxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: ricardo.neri@xxxxxxxxx
Link: http://lkml.kernel.org/r/1509935277-22138-13-git-send-email-ricardo.neri-calderon@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/x86/entry_from_vm86.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/x86/entry_from_vm86.c
+++ b/tools/testing/selftests/x86/entry_from_vm86.c
@@ -111,6 +111,11 @@ asm (
"smsw %ax\n\t"
"mov %ax, (2080)\n\t"
"int3\n\t"
+ "vmcode_umip_str:\n\t"
+ "str %eax\n\t"
+ "vmcode_umip_sldt:\n\t"
+ "sldt %eax\n\t"
+ "int3\n\t"
".size vmcode, . - vmcode\n\t"
"end_vmcode:\n\t"
".code32\n\t"
@@ -119,7 +124,8 @@ asm (
extern unsigned char vmcode[], end_vmcode[];
extern unsigned char vmcode_bound[], vmcode_sysenter[], vmcode_syscall[],
- vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_umip[];
+ vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_umip[],
+ vmcode_umip_str[], vmcode_umip_sldt[];
/* Returns false if the test was skipped. */
static bool do_test(struct vm86plus_struct *v86, unsigned long eip,
@@ -226,6 +232,16 @@ void do_umip_tests(struct vm86plus_struc
printf("[FAIL]\tAll the results of SIDT should be the same.\n");
else
printf("[PASS]\tAll the results from SIDT are identical.\n");
+
+ sethandler(SIGILL, sighandler, 0);
+ do_test(vm86, vmcode_umip_str - vmcode, VM86_SIGNAL, 0,
+ "STR instruction");
+ clearhandler(SIGILL);
+
+ sethandler(SIGILL, sighandler, 0);
+ do_test(vm86, vmcode_umip_sldt - vmcode, VM86_SIGNAL, 0,
+ "SLDT instruction");
+ clearhandler(SIGILL);
}
int main(void)
Patches currently in stable-queue which might be from ricardo.neri-calderon@xxxxxxxxxxxxxxx are
queue-4.9/selftests-x86-add-tests-for-the-str-and-sldt-instructions.patch
queue-4.9/selftests-x86-add-tests-for-user-mode-instruction-prevention.patch