[118/127] selftests/vm/pkeys: associate key on a mapped page and detect access violation

Commit Message

Andrew Morton June 4, 2020, 11:52 p.m. UTC

From: Ram Pai <[e-mail]>
Subject: selftests/vm/pkeys: associate key on a mapped page and detect access violation

Detect access-violation on a page to which access-disabled key is
associated much after the page is mapped.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ram Pai <[e-mail]>
Acked-by: Dave Hansen <[e-mail]>
Signed-off: Sandipan Das <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Florian Weimer <[e-mail]>
Cc: "Desnes A. Nunes do Rosario" <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Thiago Jung Bauermann <[e-mail]>
Cc: "Aneesh Kumar K.V" <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Michal Suchanek <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 tools/testing/selftests/vm/protection_keys.c |   19 +++++++++++++++++
 1 file changed, 19 insertions(+)

Patch

--- a/tools/testing/selftests/vm/protection_keys.c~selftests-vm-pkeys-associate-key-on-a-mapped-page-and-detect-access-violation
+++ a/tools/testing/selftests/vm/protection_keys.c
@@ -984,6 +984,24 @@  void test_read_of_access_disabled_region
 	dprintf1("*ptr: %d\n", ptr_contents);
 	expected_pkey_fault(pkey);
 }
+
+void test_read_of_access_disabled_region_with_page_already_mapped(int *ptr,
+		u16 pkey)
+{
+	int ptr_contents;
+
+	dprintf1("disabling access to PKEY[%02d], doing read @ %p\n",
+				pkey, ptr);
+	ptr_contents = read_ptr(ptr);
+	dprintf1("reading ptr before disabling the read : %d\n",
+			ptr_contents);
+	read_pkey_reg();
+	pkey_access_deny(pkey);
+	ptr_contents = read_ptr(ptr);
+	dprintf1("*ptr: %d\n", ptr_contents);
+	expected_pkey_fault(pkey);
+}
+
 void test_write_of_write_disabled_region(int *ptr, u16 pkey)
 {
 	dprintf1("disabling write access to PKEY[%02d], doing write\n", pkey);
@@ -1390,6 +1408,7 @@  void test_mprotect_pkey_on_unsupported_c
 void (*pkey_tests[])(int *ptr, u16 pkey) = {
 	test_read_of_write_disabled_region,
 	test_read_of_access_disabled_region,
+	test_read_of_access_disabled_region_with_page_already_mapped,
 	test_write_of_write_disabled_region,
 	test_write_of_access_disabled_region,
 	test_kernel_write_of_access_disabled_region,