4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Andy Lutomirski <[email protected]> commit 4831b779403a836158917d59a7ca880483c67378 upstream. If something goes wrong with pagetable setup, vsyscall=native will accidentally fall back to emulation. Make it warn and fail so that we notice. Signed-off-by: Andy Lutomirski <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Hansen <[email protected]> Cc: David Laight <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -139,6 +139,10 @@ bool emulate_vsyscall(struct pt_regs *re WARN_ON_ONCE(address != regs->ip); + /* This should be unreachable in NATIVE mode. */ + if (WARN_ON(vsyscall_mode == NATIVE)) + return false; + if (vsyscall_mode == NONE) { warn_bad_vsyscall(KERN_INFO, regs, "vsyscall attempted with vsyscall=none");
