pve-edge-kernel/patches/kernel/0116-selftests-x86-ldt_get-Add-a-few-additional-tests-for.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <[email protected]>
Date: Sat, 4 Nov 2017 04:19:52 -0700
Subject: [PATCH] selftests/x86/ldt_get: Add a few additional tests for limits
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CVE-2017-5754

We weren't testing the .limit and .limit_in_pages fields very well.
Add more tests.

This addition seems to trigger the "bits 16:19 are undefined" issue
that was fixed in an earlier patch.  I think that, at least on my
CPU, the high nibble of the limit ends in LAR bits 16:19.

Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/5601c15ea9b3113d288953fd2838b18bedf6bc67.1509794321.git.luto@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
(cherry picked from commit fec8f5ae1715a01c72ad52cb2ecd8aacaf142302)
Signed-off-by: Andy Whitcroft <[email protected]>
Signed-off-by: Kleber Sacilotto de Souza <[email protected]>
(cherry picked from commit a1cdabf77d7ed9ba02697ad8beb04adf46a7c7b8)
Signed-off-by: Fabian Grünbichler <[email protected]>
---
 tools/testing/selftests/x86/ldt_gdt.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c
index 05d0d6f49c2c..8e290c9b2c3f 100644
--- a/tools/testing/selftests/x86/ldt_gdt.c
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -403,9 +403,24 @@ static void do_simple_tests(void)
 	install_invalid(&desc, false);
 
 	desc.seg_not_present = 0;
-	desc.read_exec_only = 0;
 	desc.seg_32bit = 1;
+	desc.read_exec_only = 0;
+	desc.limit = 0xfffff;
+
 	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB);
+
+	desc.limit_in_pages = 1;
+
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB | AR_G);
+	desc.read_exec_only = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P | AR_DB | AR_G);
+	desc.contents = 1;
+	desc.read_exec_only = 0;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G);
+	desc.read_exec_only = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G);
+
+	desc.limit = 0;
 	install_invalid(&desc, true);
 }
 
-- 
2.14.2