From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:55404 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752497AbdDCNcR (ORCPT ); Mon, 3 Apr 2017 09:32:17 -0400 Subject: Patch "lib/syscall: Clear return values when no stack" has been added to the 4.10-stable tree To: keescook@chromium.org, bp@alien8.de, brgerst@gmail.com, dvlasenk@redhat.com, gregkh@linuxfoundation.org, hpa@zytor.com, jpoimboe@redhat.com, luto@kernel.org, mingo@kernel.org, peterz@infradead.org, robert@swiecki.net, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Mon, 03 Apr 2017 15:30:48 +0200 Message-ID: <149122624866134@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled lib/syscall: Clear return values when no stack to the 4.10-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: lib-syscall-clear-return-values-when-no-stack.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 854fbd6e5f60fe99e8e3a569865409fca378f143 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 23 Mar 2017 15:46:16 -0700 Subject: lib/syscall: Clear return values when no stack MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Kees Cook commit 854fbd6e5f60fe99e8e3a569865409fca378f143 upstream. Commit: aa1f1a639621 ("lib/syscall: Pin the task stack in collect_syscall()") ... added logic to handle a process stack not existing, but left sp and pc uninitialized, which can be later reported via /proc/$pid/syscall for zombie processes, potentially exposing kernel memory to userspace. Zombie /proc/$pid/syscall before: -1 0xffffffff9a060100 0xffff92f42d6ad900 Zombie /proc/$pid/syscall after: -1 0x0 0x0 Reported-by: Robert Święcki Signed-off-by: Kees Cook Reviewed-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: aa1f1a639621 ("lib/syscall: Pin the task stack in collect_syscall()") Link: http://lkml.kernel.org/r/20170323224616.GA92694@beast Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- lib/syscall.c | 1 + 1 file changed, 1 insertion(+) --- a/lib/syscall.c +++ b/lib/syscall.c @@ -11,6 +11,7 @@ static int collect_syscall(struct task_s if (!try_get_task_stack(target)) { /* Task has no stack, so the task isn't in a syscall. */ + *sp = *pc = 0; *callno = -1; return 0; } Patches currently in stable-queue which might be from keescook@chromium.org are queue-4.10/x86-mm-kaslr-exclude-efi-region-from-kaslr-va-space-randomization.patch queue-4.10/lib-syscall-clear-return-values-when-no-stack.patch