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

gregkh
2018-01-26T16:38:33Z

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