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x86/pkeys/selftests: Add PROT_EXEC test 

Under the covers, implement executable-only memory with
protection keys when userspace calls mprotect(PROT_EXEC).

But, we did not have a selftest for that.  Now we do.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171348.9EEE4BEF@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
zero-colors
Dave Hansen 2018-05-09 10:13:48 -07:00 committed by Ingo Molnar
parent 3fcd2b2d92
commit 6af17cf89e
1 changed files with 44 additions and 0 deletions
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44
tools/testing/selftests/x86/protection_keys.c
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@ -1303,6 +1303,49 @@ void test_executing_on_unreadable_memory(int *ptr, u16 pkey)
expected_pk_fault(pkey);
}
void test_implicit_mprotect_exec_only_memory(int *ptr, u16 pkey)
{
void *p1;
int scratch;
int ptr_contents;
int ret;
dprintf1("%s() start\n", __func__);
p1 = get_pointer_to_instructions();
lots_o_noops_around_write(&scratch);
ptr_contents = read_ptr(p1);
dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
/* Use a *normal* mprotect(), not mprotect_pkey(): */
ret = mprotect(p1, PAGE_SIZE, PROT_EXEC);
pkey_assert(!ret);
dprintf2("pkru: %x\n", rdpkru());
/* Make sure this is an *instruction* fault */
madvise(p1, PAGE_SIZE, MADV_DONTNEED);
lots_o_noops_around_write(&scratch);
do_not_expect_pk_fault("executing on PROT_EXEC memory");
ptr_contents = read_ptr(p1);
dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
expected_pk_fault(UNKNOWN_PKEY);
/*
* Put the memory back to non-PROT_EXEC. Should clear the
* exec-only pkey off the VMA and allow it to be readable
* again. Go to PROT_NONE first to check for a kernel bug
* that did not clear the pkey when doing PROT_NONE.
*/
ret = mprotect(p1, PAGE_SIZE, PROT_NONE);
pkey_assert(!ret);
ret = mprotect(p1, PAGE_SIZE, PROT_READ|PROT_EXEC);
pkey_assert(!ret);
ptr_contents = read_ptr(p1);
do_not_expect_pk_fault("plain read on recently PROT_EXEC area");
}
void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
{
int size = PAGE_SIZE;
@ -1327,6 +1370,7 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = {
test_kernel_gup_of_access_disabled_region,
test_kernel_gup_write_to_write_disabled_region,
test_executing_on_unreadable_memory,
test_implicit_mprotect_exec_only_memory,
test_ptrace_of_child,
test_pkey_syscalls_on_non_allocated_pkey,
test_pkey_syscalls_bad_args,