From eabdb8ca8690eedd461e61ea7780595fbbae8132 Mon Sep 17 00:00:00 2001
From: Ram Pai <linuxram@us.ibm.com>
Date: Fri, 4 May 2018 13:01:51 -0700
Subject: [PATCH] powerpc/pkeys: Detach execute_only key on !PROT_EXEC
References: FATE#322447, bsc#1078248, git-fixes
Patch-mainline: v4.18-rc1
Git-commit: eabdb8ca8690eedd461e61ea7780595fbbae8132
Disassociate the exec_key from a VMA if the VMA permission is not
PROT_EXEC anymore. Otherwise the exec_only key continues to be
associated with the vma, causing unexpected behavior.
The problem was reported on x86 by Shakeel Butt, which is also
applicable on powerpc.
Fixes: 5586cf61e108 ("powerpc: introduce execute-only pkey")
Cc: stable@vger.kernel.org # v4.16+
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/mm/pkeys.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 0eafdf01edc7..e6f500fabf5e 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -383,9 +383,9 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot,
{
/*
* If the currently associated pkey is execute-only, but the requested
- * protection requires read or write, move it back to the default pkey.
+ * protection is not execute-only, move it back to the default pkey.
*/
- if (vma_is_pkey_exec_only(vma) && (prot & (PROT_READ | PROT_WRITE)))
+ if (vma_is_pkey_exec_only(vma) && (prot != PROT_EXEC))
return 0;
/*
--
2.13.6