Thread (39 messages) flat view 39 messages, 2 authors, 2018-07-18
STALE2942d REVIEWED: 1 (0M)

Revision v14 of 4 in this series; 1 review trailer.

Revisions (4)
  1. v10 [diff vs current]
  2. v12 [diff vs current]
  3. v13 [diff vs current]
  4. v14 current

[PATCH v14 17/22] selftests/vm: associate key on a mapped page and detect access violation

From: Ram Pai <hidden>
Date: 2018-07-17 13:50:40
Also in: linux-arch, linux-kselftest, linux-mm
Subsystem: kernel selftest framework, the rest · Maintainers: Shuah Khan, Shuah Khan, Linus Torvalds

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

cc: Dave Hansen <redacted>
cc: Florian Weimer <redacted>
Signed-off-by: Ram Pai <redacted>
Acked-by: Dave Hansen <redacted>
---
 tools/testing/selftests/vm/protection_keys.c |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index 67d841e..d41b2dc 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1020,6 +1020,24 @@ void test_read_of_access_disabled_region(int *ptr, u16 pkey)
 	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);
@@ -1397,6 +1415,7 @@ void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
 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,
-- 
1.7.1
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