From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:54011 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751336AbbF2Xvf (ORCPT ); Mon, 29 Jun 2015 19:51:35 -0400 Subject: Patch "__ptrace_may_access() should not deny sub-threads" has been added to the 3.10-stable tree To: mgrondona@llnl.gov, akpm@linux-foundation.org, gregkh@linuxfoundation.org, oleg@redhat.com, torvalds@linux-foundation.org, woodard@redhat.com Cc: , From: Date: Mon, 29 Jun 2015 16:51:34 -0700 Message-ID: <1435621894195241@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 __ptrace_may_access() should not deny sub-threads to the 3.10-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: __ptrace_may_access-should-not-deny-sub-threads.patch and it can be found in the queue-3.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 73af963f9f3036dffed55c3a2898598186db1045 Mon Sep 17 00:00:00 2001 From: Mark Grondona Date: Wed, 11 Sep 2013 14:24:31 -0700 Subject: __ptrace_may_access() should not deny sub-threads From: Mark Grondona commit 73af963f9f3036dffed55c3a2898598186db1045 upstream. __ptrace_may_access() checks get_dumpable/ptrace_has_cap/etc if task != current, this can can lead to surprising results. For example, a sub-thread can't readlink("/proc/self/exe") if the executable is not readable. setup_new_exec()->would_dump() notices that inode_permission(MAY_READ) fails and then it does set_dumpable(suid_dumpable). After that get_dumpable() fails. (It is not clear why proc_pid_readlink() checks get_dumpable(), perhaps we could add PTRACE_MODE_NODUMPABLE) Change __ptrace_may_access() to use same_thread_group() instead of "task == current". Any security check is pointless when the tasks share the same ->mm. Signed-off-by: Mark Grondona Signed-off-by: Ben Woodard Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -236,7 +236,7 @@ static int __ptrace_may_access(struct ta */ int dumpable = 0; /* Don't let security modules deny introspection */ - if (task == current) + if (same_thread_group(task, current)) return 0; rcu_read_lock(); tcred = __task_cred(task); Patches currently in stable-queue which might be from mgrondona@llnl.gov are queue-3.10/__ptrace_may_access-should-not-deny-sub-threads.patch