[v13,19/24] selftests/vm: associate key on a mapped page and detect access violation

Message ID 1528937115-10132-20-git-send-email-linuxram@us.ibm.com
State New
Headers show
Series
  • selftests, powerpc, x86 : Memory Protection Keys
Related show

Commit Message

Ram Pai June 14, 2018, 12:45 a.m.
detect access-violation on a page to which access-disabled
key is associated much after the page is mapped.

cc: Dave Hansen <dave.hansen@intel.com>
cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
---
 tools/testing/selftests/vm/protection_keys.c |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)

Comments

Dave Hansen June 20, 2018, 3:16 p.m. | #1
On 06/13/2018 05:45 PM, Ram Pai wrote:
> +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);
> +}

Looks fine to me.  I'm a bit surprised we didn't do this already, which
is a good thing for this patch.

FWIW, if you took patches like this and put them first, you could
probably get it merged now.  Yes, I know it would mean redoing some of
the later code move and rename ones.

Patch

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index e8ad970..04d0249 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1024,6 +1024,24 @@  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);
@@ -1402,6 +1420,7 @@  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,