From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: Patch "fs/proc: Report eip/esp in /prod/PID/stat for coredumping" has been added to the 4.9-stable tree Date: Thu, 28 Sep 2017 15:34:28 +0200 Message-ID: <1506605668117243@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Return-path: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: john.ogness-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org, brgerst-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, marco.felsch-4vaI68m59Pc@public.gmane.org, penguin-kernel-1yMVhJb1mP/7nzcFbJAaVXf5DAMn2ifp@public.gmane.org, peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, tycho.andersen-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-commits-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org This is a note to let you know that I've just added the patch titled fs/proc: Report eip/esp in /prod/PID/stat for coredumping 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: fs-proc-report-eip-esp-in-prod-pid-stat-for-coredumping.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 know about it. >>From fd7d56270b526ca3ed0c224362e3c64a0f86687a Mon Sep 17 00:00:00 2001 From: John Ogness Date: Thu, 14 Sep 2017 11:42:17 +0200 Subject: fs/proc: Report eip/esp in /prod/PID/stat for coredumping From: John Ogness commit fd7d56270b526ca3ed0c224362e3c64a0f86687a upstream. Commit 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in /proc/PID/stat") stopped reporting eip/esp because it is racy and dangerous for executing tasks. The comment adds: As far as I know, there are no use programs that make any material use of these fields, so just get rid of them. However, existing userspace core-dump-handler applications (for example, minicoredumper) are using these fields since they provide an excellent cross-platform interface to these valuable pointers. So that commit introduced a user space visible regression. Partially revert the change and make the readout possible for tasks with the proper permissions and only if the target task has the PF_DUMPCORE flag set. Fixes: 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in> /proc/PID/stat") Reported-by: Marco Felsch Signed-off-by: John Ogness Reviewed-by: Andy Lutomirski Cc: Tycho Andersen Cc: Kees Cook Cc: Peter Zijlstra Cc: Brian Gerst Cc: Tetsuo Handa Cc: Borislav Petkov Cc: Al Viro Cc: Linux API Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/87poatfwg6.fsf-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- fs/proc/array.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -60,6 +60,7 @@ #include #include #include +#include #include #include #include @@ -416,7 +417,15 @@ static int do_task_stat(struct seq_file * esp and eip are intentionally zeroed out. There is no * non-racy way to read them without freezing the task. * Programs that need reliable values can use ptrace(2). + * + * The only exception is if the task is core dumping because + * a program is not able to use ptrace(2) in that case. It is + * safe because the task has stopped executing permanently. */ + if (permitted && (task->flags & PF_DUMPCORE)) { + eip = KSTK_EIP(task); + esp = KSTK_ESP(task); + } } get_task_comm(tcomm, task); Patches currently in stable-queue which might be from john.ogness-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org are queue-4.9/fs-proc-report-eip-esp-in-prod-pid-stat-for-coredumping.patch From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49024 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753186AbdI1Nei (ORCPT ); Thu, 28 Sep 2017 09:34:38 -0400 Subject: Patch "fs/proc: Report eip/esp in /prod/PID/stat for coredumping" has been added to the 4.9-stable tree To: john.ogness@linutronix.de, akpm@linux-foundation.org, bp@alien8.de, brgerst@gmail.com, gregkh@linuxfoundation.org, keescook@chromium.org, linux-api@vger.kernel.org, luto@kernel.org, marco.felsch@preh.de, penguin-kernel@i-love.sakura.ne.jp, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, tycho.andersen@canonical.com, viro@zeniv.linux.org.uk Cc: , From: Date: Thu, 28 Sep 2017 15:34:28 +0200 Message-ID: <1506605668117243@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 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 fs/proc: Report eip/esp in /prod/PID/stat for coredumping 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: fs-proc-report-eip-esp-in-prod-pid-stat-for-coredumping.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 know about it. >>From fd7d56270b526ca3ed0c224362e3c64a0f86687a Mon Sep 17 00:00:00 2001 From: John Ogness Date: Thu, 14 Sep 2017 11:42:17 +0200 Subject: fs/proc: Report eip/esp in /prod/PID/stat for coredumping From: John Ogness commit fd7d56270b526ca3ed0c224362e3c64a0f86687a upstream. Commit 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in /proc/PID/stat") stopped reporting eip/esp because it is racy and dangerous for executing tasks. The comment adds: As far as I know, there are no use programs that make any material use of these fields, so just get rid of them. However, existing userspace core-dump-handler applications (for example, minicoredumper) are using these fields since they provide an excellent cross-platform interface to these valuable pointers. So that commit introduced a user space visible regression. Partially revert the change and make the readout possible for tasks with the proper permissions and only if the target task has the PF_DUMPCORE flag set. Fixes: 0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in> /proc/PID/stat") Reported-by: Marco Felsch Signed-off-by: John Ogness Reviewed-by: Andy Lutomirski Cc: Tycho Andersen Cc: Kees Cook Cc: Peter Zijlstra Cc: Brian Gerst Cc: Tetsuo Handa Cc: Borislav Petkov Cc: Al Viro Cc: Linux API Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/87poatfwg6.fsf@linutronix.de Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- fs/proc/array.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -60,6 +60,7 @@ #include #include #include +#include #include #include #include @@ -416,7 +417,15 @@ static int do_task_stat(struct seq_file * esp and eip are intentionally zeroed out. There is no * non-racy way to read them without freezing the task. * Programs that need reliable values can use ptrace(2). + * + * The only exception is if the task is core dumping because + * a program is not able to use ptrace(2) in that case. It is + * safe because the task has stopped executing permanently. */ + if (permitted && (task->flags & PF_DUMPCORE)) { + eip = KSTK_EIP(task); + esp = KSTK_ESP(task); + } } get_task_comm(tcomm, task); Patches currently in stable-queue which might be from john.ogness@linutronix.de are queue-4.9/fs-proc-report-eip-esp-in-prod-pid-stat-for-coredumping.patch