linux-kernel - [PATCH 4.16 241/279] x86/pkeys/selftests: Allow faults on unknown keys

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Message-Id: <20180618080618.756215501@linuxfoundation.org>
Date:   Mon, 18 Jun 2018 10:13:46 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dave Hansen <dave.hansen@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Michael Ellermen <mpe@...erman.id.au>,
        Peter Zijlstra <peterz@...radead.org>,
        Ram Pai <linuxram@...ibm.com>, Shuah Khan <shuah@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>, linux-mm@...ck.org,
        Ingo Molnar <mingo@...nel.org>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.16 241/279] x86/pkeys/selftests: Allow faults on unknown keys

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Hansen <dave.hansen@...ux.intel.com>

[ Upstream commit 7e7fd67ca39335a49619729821efb7cbdd674eb0 ]

The exec-only pkey is allocated inside the kernel and userspace
is not told what it is.  So, allow PK faults to occur that have
an unknown key.

Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Michael Ellermen <mpe@...erman.id.au>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ram Pai <linuxram@...ibm.com>
Cc: Shuah Khan <shuah@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/20180509171345.7FC7DA00@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 tools/testing/selftests/x86/protection_keys.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/x86/protection_keys.c
+++ b/tools/testing/selftests/x86/protection_keys.c
@@ -921,13 +921,21 @@ void *malloc_pkey(long size, int prot, u
 }
 
 int last_pkru_faults;
+#define UNKNOWN_PKEY -2
 void expected_pk_fault(int pkey)
 {
 	dprintf2("%s(): last_pkru_faults: %d pkru_faults: %d\n",
 			__func__, last_pkru_faults, pkru_faults);
 	dprintf2("%s(%d): last_si_pkey: %d\n", __func__, pkey, last_si_pkey);
 	pkey_assert(last_pkru_faults + 1 == pkru_faults);
-	pkey_assert(last_si_pkey == pkey);
+
+       /*
+	* For exec-only memory, we do not know the pkey in
+	* advance, so skip this check.
+	*/
+	if (pkey != UNKNOWN_PKEY)
+		pkey_assert(last_si_pkey == pkey);
+
 	/*
 	 * The signal handler shold have cleared out PKRU to let the
 	 * test program continue.  We now have to restore it.