Patch "vsyscall: Fix permissions for emulate mode with KAISER/PTI" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    vsyscall: Fix permissions for emulate mode with KAISER/PTI

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     vsyscall-fix-permissions-for-emulate-mode-with-kaiser-pti.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ben.hutchings@codethink.co.uk  Fri Jan 26 17:35:59 2018
From: Ben Hutchings <ben.hutchings@codethink.co.uk>
Date: Fri, 26 Jan 2018 16:23:02 +0000
Subject: vsyscall: Fix permissions for emulate mode with KAISER/PTI
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Borislav Petkov <bp@suse.de>, Hugh Dickins <hughd@google.com>, stable@vger.kernel.org
Message-ID: <20180126162302.ei4tmiltl73npmr6@xylophone.i.decadent.org.uk>

From: Ben Hutchings <ben.hutchings@codethink.co.uk>

The backport of KAISER to 4.4 turned vsyscall emulate mode into native
mode.  Add a vsyscall_pgprot variable to hold the correct page
protections, like Borislav and Hugh did for 3.2 and 3.18.

Cc: Borislav Petkov <bp@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 arch/x86/entry/vsyscall/vsyscall_64.c |    7 ++++---
 arch/x86/include/asm/vsyscall.h       |    1 +
 arch/x86/mm/kaiser.c                  |    2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -46,6 +46,7 @@ static enum { EMULATE, NATIVE, NONE } vs
 #else
 	EMULATE;
 #endif
+unsigned long vsyscall_pgprot = __PAGE_KERNEL_VSYSCALL;
 
 static int __init vsyscall_setup(char *str)
 {
@@ -336,11 +337,11 @@ void __init map_vsyscall(void)
 	extern char __vsyscall_page;
 	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
 
+	if (vsyscall_mode != NATIVE)
+		vsyscall_pgprot = __PAGE_KERNEL_VVAR;
 	if (vsyscall_mode != NONE)
 		__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
-			     vsyscall_mode == NATIVE
-			     ? PAGE_KERNEL_VSYSCALL
-			     : PAGE_KERNEL_VVAR);
+			     __pgprot(vsyscall_pgprot));
 
 	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
 		     (unsigned long)VSYSCALL_ADDR);
--- a/arch/x86/include/asm/vsyscall.h
+++ b/arch/x86/include/asm/vsyscall.h
@@ -13,6 +13,7 @@ extern void map_vsyscall(void);
  */
 extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address);
 extern bool vsyscall_enabled(void);
+extern unsigned long vsyscall_pgprot;
 #else
 static inline void map_vsyscall(void) {}
 static inline bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -344,7 +344,7 @@ void __init kaiser_init(void)
 	if (vsyscall_enabled())
 		kaiser_add_user_map_early((void *)VSYSCALL_ADDR,
 					  PAGE_SIZE,
-					   __PAGE_KERNEL_VSYSCALL);
+					  vsyscall_pgprot);
 
 	for_each_possible_cpu(cpu) {
 		void *percpu_vaddr = __per_cpu_user_mapped_start +


Patches currently in stable-queue which might be from ben.hutchings@codethink.co.uk are

queue-4.9/vsyscall-fix-permissions-for-emulate-mode-with-kaiser-pti.patch