From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@kernel.org>
Date: Sat, 4 Nov 2017 04:19:51 -0700
Subject: [PATCH] selftests/x86/ldt_gdt: Run most existing LDT test cases
 against the GDT as well
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CVE-2017-5754

Now that the main test infrastructure supports the GDT, run tests
that will pass the kernel's GDT permission tests against the GDT.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/686a1eda63414da38fcecc2412db8dba1ae40581.1509794321.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit adedf2893c192dd09b1cc2f2dcfdd7cad99ec49d)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit f05c092307d8479094d83d4337d66e6e86e730a9)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 tools/testing/selftests/x86/ldt_gdt.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c
index 337f217d0ae9..05d0d6f49c2c 100644
--- a/tools/testing/selftests/x86/ldt_gdt.c
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -188,7 +188,15 @@ static bool install_valid_mode(const struct user_desc *d, uint32_t ar,
 
 static bool install_valid(const struct user_desc *desc, uint32_t ar)
 {
-	return install_valid_mode(desc, ar, false, true);
+	bool ret = install_valid_mode(desc, ar, false, true);
+
+	if (desc->contents <= 1 && desc->seg_32bit &&
+	    !desc->seg_not_present) {
+		/* Should work in the GDT, too. */
+		install_valid_mode(desc, ar, false, false);
+	}
+
+	return ret;
 }
 
 static void install_invalid(const struct user_desc *desc, bool oldmode)
-- 
2.14.2

