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From: Christian Brauner <christian.brauner@ubuntu.com>
To: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Kees Cook <keescook@chromium.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Jann Horn <jannh@google.com>, Jonathan Corbet <corbet@lwn.net>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Oleg Nesterov <oleg@redhat.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Andrei Vagin <avagin@gmail.com>, Ingo Molnar <mingo@kernel.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Yuyang Du <duyuyang@gmail.com>,
	David Hildenbrand <david@redhat.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	David Howells <dhowells@redhat.com>,
	James Morris <jamorris@linux.microsoft.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Shakeel Butt <shakeelb@google.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Christian Kellner <christian@kellner.me>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Aleksa Sarai <cyphar@cyphar.com>,
	"Dmitry V. Levin" <ldv@altlinux.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCHv4] exec: Fix a deadlock in ptrace
Date: Tue, 3 Mar 2020 09:34:25 +0100
Message-ID: <20200303083425.jbf43axuymttijfv@wittgenstein> (raw)
In-Reply-To: <AM6PR03MB5170A15099986CEC3189F251E4E40@AM6PR03MB5170.eurprd03.prod.outlook.com>

On Tue, Mar 03, 2020 at 08:08:26AM +0000, Bernd Edlinger wrote:
> On 3/3/20 6:29 AM, Kees Cook wrote:
> > On Tue, Mar 03, 2020 at 04:54:34AM +0000, Bernd Edlinger wrote:
> >> On 3/3/20 3:26 AM, Kees Cook wrote:
> >>> On Mon, Mar 02, 2020 at 10:18:07PM +0000, Bernd Edlinger wrote:
> >>>> [...]
> >>>
> >>> If I'm reading this patch correctly, this changes the lifetime of the
> >>> cred_guard_mutex lock to be:
> >>> 	- during prepare_bprm_creds()
> >>> 	- from flush_old_exec() through install_exec_creds()
> >>> Before, cred_guard_mutex was held from prepare_bprm_creds() through
> >>> install_exec_creds().
> > 
> > BTW, I think the effect of this change (i.e. my paragraph above) should
> > be distinctly called out in the commit log if this solution moves
> > forward.
> > 
> 
> Okay, will do.
> 
> >>> That means, for example, that check_unsafe_exec()'s documented invariant
> >>> is violated:
> >>>     /*
> >>>      * determine how safe it is to execute the proposed program
> >>>      * - the caller must hold ->cred_guard_mutex to protect against
> >>>      *   PTRACE_ATTACH or seccomp thread-sync
> >>>      */
> >>
> >> Oh, right, I haven't understood that hint...
> > 
> > I know no_new_privs is checked there, but I haven't studied the
> > PTRACE_ATTACH part of that comment. If that is handled with the new
> > check, this comment should be updated.
> > 
> 
> Okay, I change that comment to:
> 
> /*
>  * determine how safe it is to execute the proposed program
>  * - the caller must have set ->cred_locked_in_execve to protect against
>  *   PTRACE_ATTACH or seccomp thread-sync
>  */
> 
> >>> I think it also means that the potentially multiple invocations
> >>> of bprm_fill_uid() (via prepare_binprm() via binfmt_script.c and
> >>> binfmt_misc.c) would be changing bprm->cred details (uid, gid) without
> >>> a lock (another place where current's no_new_privs is evaluated).
> >>
> >> So no_new_privs can change from 0->1, but should not
> >> when execve is running.
> >>
> >> As long as the calling thread is in execve it won't do this,
> >> and the only other place, where it may set for other threads
> >> is in seccomp_sync_threads, but that can easily be avoided see below.
> > 
> > Yeah, everything was fine until I had to go complicate things with
> > TSYNC. ;) The real goal is making sure an exec cannot gain privs while
> > later gaining a seccomp filter from an unpriv process. The no_new_privs
> > flag was used to control this, but it required that the filter not get
> > applied during exec.
> > 
> >>> Related, it also means that cred_guard_mutex is unheld for every
> >>> invocation of search_binary_handler() (which can loop via the previously
> >>> mentioned binfmt_script.c and binfmt_misc.c), if any of them have hidden
> >>> dependencies on cred_guard_mutex. (Thought I only see bprm_fill_uid()
> >>> currently.)
> >>>
> >>> For seccomp, the expectations about existing thread states risks races
> >>> too. There are two locks held for TSYNC:
> >>> - current->sighand->siglock is held to keep new threads from
> >>>   appearing/disappearing, which would destroy filter refcounting and
> >>>   lead to memory corruption.
> >>
> >> I don't understand what you mean here.
> >> How can this lead to memory corruption?
> > 
> > Mainly this is a matter of how seccomp manages its filter hierarchy
> > (since the filters are shared through process ancestry), so if a thread
> > appears in the middle of TSYNC it may be racing another TSYNC and break
> > ancestry, leading to bad reference counting on process death, etc.
> > (Though, yes, with refcount_t now, things should never corrupt, just
> > waste memory.)
> > 
> 
> I assume for now, that the current->sighand->siglock held while iterating all
> threads is sufficient here.
> 
> >>> - cred_guard_mutex is held to keep no_new_privs in sync with filters to
> >>>   avoid no_new_privs and filter confusion during exec, which could
> >>>   lead to exploitable setuid conditions (see below).
> >>>
> >>> Just racing a malicious thread during TSYNC is not a very strong
> >>> example (a malicious thread could do lots of fun things to "current"
> >>> before it ever got near calling TSYNC), but I think there is the risk
> >>> of mismatched/confused states that we don't want to allow. One is a
> >>> particularly bad state that could lead to privilege escalations (in the
> >>> form of the old "sendmail doesn't check setuid" flaw; if a setuid process
> >>> has a filter attached that silently fails a priv-dropping setuid call
> >>> and continues execution with elevated privs, it can be tricked into
> >>> doing bad things on behalf of the unprivileged parent, which was the
> >>> primary goal of the original use of cred_guard_mutex with TSYNC[1]):
> >>>
> >>> thread A clones thread B
> >>> thread B starts setuid exec
> >>> thread A sets no_new_privs
> >>> thread A calls seccomp with TSYNC
> >>> thread A in seccomp_sync_threads() sets seccomp filter on self and thread B
> >>> thread B passes check_unsafe_exec() with no_new_privs unset
> >>> thread B reaches bprm_fill_uid() with no_new_privs unset and gains privs
> >>> thread A still in seccomp_sync_threads() sets no_new_privs on thread B
> >>> thread B finishes exec, now running with elevated privs, a filter chosen
> >>>          by thread A, _and_ nnp set (which doesn't matter)
> >>>
> >>> With the original locking, thread B will fail check_unsafe_exec()
> >>> because filter and nnp state are changed together, with "atomicity"
> >>> protected by the cred_guard_mutex.
> >>>
> >>
> >> Ah, good point, thanks!
> >>
> >> This can be fixed by checking current->signal->cred_locked_for_ptrace
> >> while the cred_guard_mutex is locked, like this for instance:
> >>
> >> diff --git a/kernel/seccomp.c b/kernel/seccomp.c
> >> index b6ea3dc..377abf0 100644
> >> --- a/kernel/seccomp.c
> >> +++ b/kernel/seccomp.c
> >> @@ -342,6 +342,9 @@ static inline pid_t seccomp_can_sync_threads(void)
> >>         BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
> >>         assert_spin_locked(&current->sighand->siglock);
> >>  
> >> +       if (current->signal->cred_locked_for_ptrace)
> >> +               return -EAGAIN;
> >> +
> > 
> > Hmm. I guess something like that could work. TSYNC expects to be able to
> > report _which_ thread wrecked the call, though... I wonder if in_execve
> > could be used to figure out the offending thread. Hm, nope, that would
> > be outside of lock too (and all users are "current" right now, so the
> > lock wasn't needed before).
> > 
> 
> I could move that in_execve = 1 to prepare_bprm_creds, if it really matters,
> but the caller will die quickly and cannot do anything with that information
> when another thread executes execve, right?
> 
> >>         /* Validate all threads being eligible for synchronization. */
> >>         caller = current;
> >>         for_each_thread(caller, thread) {
> >>
> >>
> >>> And this is just the bad state I _can_ see. I'm worried there are more...
> >>>
> >>> All this said, I do see a small similarity here to the work I did to
> >>> stabilize stack rlimits (there was an ongoing problem with making multiple
> >>> decisions for the bprm based on current's state -- but current's state
> >>> was mutable during exec). For this, I saved rlim_stack to bprm and ignored
> >>> current's copy until exec ended and then stored bprm's copy into current.
> >>> If the only problem anyone can see here is the handling of no_new_privs,
> >>> we might be able to solve that similarly, at least disentangling tsync/nnp
> >>> from cred_guard_mutex.
> >>>
> >>
> >> I still think that is solvable with using cred_locked_for_ptrace and
> >> simply make the tsync fail if it would otherwise be blocked.
> > 
> > I wonder if we can find a better name than "cred_locked_for_ptrace"?
> > Maybe "cred_unfinished" or "cred_locked_in_exec" or something?
> > 
> 
> Yeah, I'd go with "cred_locked_in_execve".
> 
> > And the comment on bool cred_locked_for_ptrace should mention that
> > access is only allowed under cred_guard_mutex lock.
> > 
> 
> okay.
> 
> >>>> +	sig->cred_locked_for_ptrace = false;
> > 
> > This is redundant to the zalloc -- I think you can drop it (unless
> > someone wants to keep it for clarify?)
> > 
> 
> I'll remove that here and in init/init_task.c
> 
> > Also, I think cred_locked_for_ptrace needs checking deeper, in
> > __ptrace_may_access(), not in ptrace_attach(), since LOTS of things make
> > calls to ptrace_may_access() holding cred_guard_mutex, expecting that to
> > be sufficient to see a stable version of the thread...
> > 
> 
> No, these need to be addressed individually, but most users just want
> to know if the current credentials are sufficient at this moment, but will
> not change the credentials, as ptrace and TSYNC do. 
> 
> BTW: Not all users have cred_guard_mutex, see mm/migrate.c,
> mm/mempolicy.c, kernel/futex.c, fs/proc/namespaces.c etc.
> So adding an access to cred_locked_for_execve in ptrace_may_access is
> probably not an option.
> 
> However, one nice added value by this change is this:
> 
> void *thread(void *arg)
> {
> 	ptrace(PTRACE_TRACEME, 0,0,0);
> 	return NULL;
> }
> 
> int main(void)
> {
> 	int pid = fork();
> 
> 	if (!pid) {
> 		pthread_t pt;
> 		pthread_create(&pt, NULL, thread, NULL);
> 		pthread_join(pt, NULL);
> 		execlp("echo", "echo", "passed", NULL);
> 	}
> 
> 	sleep(1000);
> 	ptrace(PTRACE_ATTACH, pid, 0,0);
> 	kill(pid, SIGCONT);
> 	return 0;
> }
> 
> cat /proc/3812/stack 
> [<0>] flush_old_exec+0xbf/0x760
> [<0>] load_elf_binary+0x35a/0x16c0
> [<0>] search_binary_handler+0x97/0x1d0
> [<0>] __do_execve_file.isra.40+0x624/0x920
> [<0>] __x64_sys_execve+0x49/0x60
> [<0>] do_syscall_64+0x64/0x220
> [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> 
> 
> > (I remain very nervous about weakening cred_guard_mutex without
> > addressing the many many users...)
> > 
> 
> They need to be looked at closely, that's pretty clear.
> Most fall in the class, that just the current credentials need
> to stay stable for a certain time.

I remain rather set on wanting some very basic tests with this change.
Imho, looking through tools/testing/selftests again we don't have nearly
enough for these codepaths; not to say none. Basically, if someone wants
to make a change affecting the current problem we should really have at
least a single simple test/reproducer that can be run without digging
through lore. And hopefully over time we'll have more tests.

Christian

  reply index

Thread overview: 203+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-01 11:27 [PATCH] " Bernd Edlinger
2020-03-01 15:13 ` Aleksa Sarai
2020-03-01 15:58   ` Christian Brauner
2020-03-01 17:46     ` Bernd Edlinger
2020-03-01 18:20       ` Christian Brauner
2020-03-01 17:24   ` Bernd Edlinger
2020-03-01 18:21 ` Jann Horn
2020-03-01 18:52   ` Christian Brauner
2020-03-01 19:00     ` Bernd Edlinger
2020-03-01 20:00     ` Jann Horn
2020-03-01 20:34       ` [PATCHv2] " Bernd Edlinger
2020-03-02  6:38         ` Eric W. Biederman
2020-03-02 15:43           ` Bernd Edlinger
2020-03-02 15:57             ` Eric W. Biederman
2020-03-02 16:02               ` Bernd Edlinger
2020-03-02 16:17                 ` Eric W. Biederman
2020-03-02 16:43                   ` Jann Horn
2020-03-02 17:01                     ` Bernd Edlinger
2020-03-02 17:37                       ` Jann Horn
2020-03-02 17:42                         ` christian
2020-03-02 18:08                           ` Jann Horn
2020-03-02 20:10                             ` [PATCHv3] " Bernd Edlinger
2020-03-02 20:28                               ` Bernd Edlinger
2020-03-02 17:13                   ` [PATCHv2] " Bernd Edlinger
2020-03-02 21:49                     ` Eric W. Biederman
2020-03-02 22:00                       ` Bernd Edlinger
2020-03-02 22:18                       ` [PATCHv4] " Bernd Edlinger
2020-03-03  2:26                         ` Kees Cook
2020-03-03  4:54                           ` Bernd Edlinger
2020-03-03  5:29                             ` Kees Cook
2020-03-03  8:08                               ` Bernd Edlinger
2020-03-03  8:34                                 ` Christian Brauner [this message]
2020-03-03  8:43                                   ` Christian Brauner
2020-03-04 15:30                                 ` Christian Brauner
2020-03-03  8:58                           ` Christian Brauner
2020-03-03 10:34                             ` Bernd Edlinger
2020-03-03 11:23                               ` Bernd Edlinger
2020-03-03 14:20                                 ` Christian Brauner
2020-03-03 13:02                             ` [PATCHv5] " Bernd Edlinger
2020-03-03 15:18                               ` Eric W. Biederman
2020-03-03 16:48                                 ` Bernd Edlinger
2020-03-03 17:01                                   ` Christian Brauner
2020-03-03 17:20                                     ` Christian Brauner
2020-03-03 20:08                                   ` Eric W. Biederman
2020-03-04 14:37                                     ` Bernd Edlinger
2020-03-04 16:33                                       ` Eric W. Biederman
2020-03-04 21:49                                         ` Bernd Edlinger
2020-03-04 21:56                                         ` [PATCHv6] " Bernd Edlinger
2020-03-05 18:36                                           ` Bernd Edlinger
2020-03-05 21:14                                             ` [PATCH 0/2] Infrastructure to allow fixing exec deadlocks Eric W. Biederman
2020-03-05 21:15                                               ` [PATCH 1/2] exec: Properly mark the point of no return Eric W. Biederman
2020-03-05 22:34                                                 ` Bernd Edlinger
2020-03-06  5:19                                                   ` Eric W. Biederman
2020-03-05 22:56                                                 ` Bernd Edlinger
2020-03-06  5:09                                                   ` Eric W. Biederman
2020-03-06 16:26                                                     ` Bernd Edlinger
2020-03-06 17:16                                                       ` Eric W. Biederman
2020-03-05 21:16                                               ` [PATCH 2/2] exec: Add a exec_update_mutex to replace cred_guard_mutex Eric W. Biederman
2020-03-05 21:51                                                 ` Bernd Edlinger
2020-03-06  5:17                                                   ` Eric W. Biederman
2020-03-06 11:46                                                     ` Bernd Edlinger
2020-03-06 21:18                                                       ` Eric W. Biederman
2020-03-06 19:16                                                     ` Bernd Edlinger
2020-03-06 21:58                                                       ` Eric W. Biederman
2020-03-06 22:29                                                         ` Eric W. Biederman
2020-03-07  1:03                                                           ` Eric W. Biederman
2020-03-08 12:58                                                             ` [PATCH] exec: make de_thread alloc new signal struct earlier Bernd Edlinger
2020-03-08 18:12                                                               ` Eric W. Biederman
2020-03-05 22:31                                               ` [PATCH 0/2] Infrastructure to allow fixing exec deadlocks Bernd Edlinger
2020-03-06  5:06                                                 ` Eric W. Biederman
2020-03-08 21:34                                               ` [PATCH 0/5] " Eric W. Biederman
2020-03-08 21:35                                                 ` [PATCH v2 1/5] exec: Only compute current once in flush_old_exec Eric W. Biederman
2020-03-09 13:56                                                   ` Bernd Edlinger
2020-03-09 17:34                                                     ` Eric W. Biederman
2020-03-09 17:56                                                       ` Bernd Edlinger
2020-03-09 19:27                                                         ` Bernd Edlinger
2020-03-10 20:17                                                   ` Kees Cook
2020-03-10 21:12                                                   ` Christian Brauner
2020-03-08 21:36                                                 ` [PATCH v2 2/5] exec: Factor unshare_sighand out of de_thread and call it separately Eric W. Biederman
2020-03-09 19:28                                                   ` Bernd Edlinger
2020-03-10 20:29                                                   ` Kees Cook
2020-03-10 20:34                                                     ` Bernd Edlinger
2020-03-10 20:57                                                       ` Kees Cook
2020-03-10 21:21                                                   ` Christian Brauner
2020-03-08 21:36                                                 ` [PATCH v2 3/5] exec: Move cleanup of posix timers on exec out of de_thread Eric W. Biederman
2020-03-09 19:30                                                   ` Bernd Edlinger
2020-03-09 19:59                                                   ` Christian Brauner
2020-03-09 20:06                                                     ` Eric W. Biederman
2020-03-09 20:17                                                       ` Christian Brauner
2020-03-09 20:48                                                         ` Eric W. Biederman
2020-03-10  8:55                                                           ` Christian Brauner
2020-03-10 18:52                                                             ` [PATCH] pidfd: Stop taking cred_guard_mutex Eric W. Biederman
2020-03-10 19:15                                                               ` Christian Brauner
2020-03-10 19:16                                                               ` Jann Horn
2020-03-10 19:27                                                                 ` Eric W. Biederman
2020-03-10 20:00                                                                   ` Jann Horn
2020-03-10 20:10                                                                     ` Jann Horn
2020-03-10 20:22                                                                       ` Bernd Edlinger
2020-03-11  6:11                                                                         ` Bernd Edlinger
2020-03-11 14:56                                                                           ` Jann Horn
2020-03-10 20:57                                                                       ` Eric W. Biederman
2020-03-10 21:29                                                                         ` Christian Brauner
2020-03-11 18:49                                                                         ` Kees Cook
2020-03-14  9:12                                                                           ` [PATCH] pidfd: Use new infrastructure to fix deadlocks in execve Bernd Edlinger
2020-03-10 20:16                                                           ` [PATCH v2 3/5] exec: Move cleanup of posix timers on exec out of de_thread Kees Cook
2020-03-10 20:31                                                   ` Kees Cook
2020-03-10 20:57                                                   ` Jann Horn
2020-03-10 21:05                                                     ` Eric W. Biederman
2020-03-10 21:22                                                   ` Christian Brauner
2020-03-08 21:38                                                 ` [PATCH v2 4/5] exec: Move exec_mmap right after de_thread in flush_old_exec Eric W. Biederman
2020-03-09 19:34                                                   ` Bernd Edlinger
2020-03-09 19:45                                                     ` Eric W. Biederman
2020-03-09 19:52                                                       ` Bernd Edlinger
2020-03-09 19:58                                                         ` Eric W. Biederman
2020-03-09 20:03                                                           ` Bernd Edlinger
2020-03-09 20:35                                                             ` Eric W. Biederman
2020-03-10 20:44                                                   ` Kees Cook
2020-03-10 21:20                                                     ` Eric W. Biederman
2020-03-10 20:47                                                   ` Kees Cook
2020-03-10 21:09                                                     ` Eric W. Biederman
2020-03-08 21:38                                                 ` [PATCH v2 5/5] exec: Add a exec_update_mutex to replace cred_guard_mutex Eric W. Biederman
2020-03-09 13:45                                                   ` Bernd Edlinger
2020-03-09 17:40                                                     ` Eric W. Biederman
2020-03-09 18:01                                                       ` Bernd Edlinger
2020-03-09 18:10                                                         ` Eric W. Biederman
2020-03-09 18:24                                                           ` Eric W. Biederman
2020-03-09 18:36                                                             ` Eric W. Biederman
2020-03-09 18:47                                                               ` Bernd Edlinger
2020-03-09 19:02                                                                 ` Eric W. Biederman
2020-03-09 19:24                                                                   ` Bernd Edlinger
2020-03-09 19:35                                                                     ` Eric W. Biederman
2020-03-09 19:39                                                                     ` Eric W. Biederman
2020-03-10 13:43                                                                       ` [PATCH 0/4] Use new infrastructure to fix deadlocks in execve Bernd Edlinger
2020-03-10 15:35                                                                         ` Eric W. Biederman
2020-03-10 17:44                                                                           ` [PATCH 0/4] Use new infrastructure in more simple cases Bernd Edlinger
2020-03-10 17:45                                                                           ` [PATCH 1/4] kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve Bernd Edlinger
2020-03-10 19:01                                                                             ` Eric W. Biederman
2020-03-10 19:42                                                                               ` Bernd Edlinger
2020-03-10 17:45                                                                           ` [PATCH 2/4] proc: " Bernd Edlinger
2020-03-11 18:59                                                                             ` Kees Cook
2020-03-11 19:10                                                                             ` Kees Cook
2020-03-11 19:38                                                                               ` Bernd Edlinger
2020-03-10 17:45                                                                           ` [PATCH 3/4] proc: io_accounting: " Bernd Edlinger
2020-03-10 19:06                                                                             ` Eric W. Biederman
2020-03-10 20:19                                                                               ` Bernd Edlinger
2020-03-10 21:25                                                                                 ` Eric W. Biederman
2020-03-11 19:08                                                                             ` Kees Cook
2020-03-11 19:48                                                                               ` Bernd Edlinger
2020-03-11 19:48                                                                               ` Eric W. Biederman
2020-03-10 17:45                                                                           ` [PATCH 4/4] perf: " Bernd Edlinger
2020-03-10 13:43                                                                       ` [PATCH 1/4] exec: Fix a deadlock in ptrace Bernd Edlinger
2020-03-10 15:13                                                                         ` Eric W. Biederman
2020-03-10 15:17                                                                           ` Bernd Edlinger
2020-03-10 21:00                                                                         ` Kees Cook
2020-03-10 13:44                                                                       ` [PATCH 2/4] selftests/ptrace: add test cases for dead-locks Bernd Edlinger
2020-03-10 21:36                                                                         ` Kees Cook
2020-03-10 22:41                                                                         ` Dmitry V. Levin
2020-03-10 13:44                                                                       ` [PATCH 3/4] mm: docs: Fix a comment in process_vm_rw_core Bernd Edlinger
2020-03-11 18:53                                                                         ` Kees Cook
2020-03-10 13:44                                                                       ` [PATCH 4/4] kernel: doc: remove outdated comment cred.c Bernd Edlinger
2020-03-11 18:54                                                                         ` Kees Cook
2020-03-09 19:33                                                                   ` [PATCH v2 5/5] exec: Add a exec_update_mutex to replace cred_guard_mutex Dmitry V. Levin
2020-03-09 19:42                                                                     ` Eric W. Biederman
2020-03-10 20:55                                                                   ` Kees Cook
2020-03-10 21:02                                                                     ` Eric W. Biederman
2020-03-10 21:21                                                   ` Jann Horn
2020-03-10 21:30                                                     ` Eric W. Biederman
2020-03-10 23:21                                                       ` Jann Horn
2020-03-11  0:15                                                         ` Eric W. Biederman
2020-03-11  6:33                                                           ` Bernd Edlinger
2020-03-11 16:29                                                             ` Eric W. Biederman
2020-03-11 13:18                                                   ` Qian Cai
2020-03-12 10:27                                                   ` Kirill Tkhai
2020-03-12 12:24                                                     ` Eric W. Biederman
2020-03-12 13:45                                                       ` Kirill Tkhai
2020-03-12 14:38                                                         ` Eric W. Biederman
2020-03-12 15:23                                                           ` Kirill Tkhai
2020-03-13  1:05                                                           ` Bernd Edlinger
2020-03-13  9:13                                                             ` Kirill Tkhai
2020-03-14  9:11                                                               ` [PATCH v3 " Bernd Edlinger
2020-03-17  8:56                                                                 ` Kirill Tkhai
2020-03-17 21:53                                                                   ` Bernd Edlinger
2020-03-18 12:22                                                                     ` Kirill Tkhai
2020-03-18 20:06                                                                       ` Bernd Edlinger
2020-03-19  7:13                                                                         ` Kirill Tkhai
2020-03-19  7:19                                                                           ` Bernd Edlinger
2020-03-19  9:11                                                                           ` [PATCH v4 3/5] " Bernd Edlinger
2020-03-19  9:13                                                                             ` Bernd Edlinger
2020-03-19  9:19                                                                               ` Greg Kroah-Hartman
2020-03-19  9:20                                                                                 ` Bernd Edlinger
2020-03-21 22:53                                                                                 ` Bernd Edlinger
2020-03-14  9:12                                                               ` [PATCH 0/2] exec: Fix dead-lock in de_thread with ptrace_attach Bernd Edlinger
2020-03-14  9:12                                                               ` [PATCH 1/2] " Bernd Edlinger
2020-03-14  9:13                                                               ` [PATCH 2/2] doc: Update documentation of ->exec_*_mutex Bernd Edlinger
2020-03-14  9:57                                                               ` [PATCH v2 5/5] exec: Add a exec_update_mutex to replace cred_guard_mutex Bernd Edlinger
2020-03-14 10:02                                                                 ` Bernd Edlinger
2020-03-17  8:58                                                                   ` Kirill Tkhai
2020-03-09 13:58                                                 ` [PATCH 0/5] Infrastructure to allow fixing exec deadlocks Bernd Edlinger
2020-03-03 16:50                                 ` [PATCHv5] exec: Fix a deadlock in ptrace Christian Brauner
2020-03-02 12:28         ` [PATCHv2] " Oleg Nesterov
2020-03-02 15:56           ` Bernd Edlinger
2020-03-02  7:47       ` [PATCH] " Christian Brauner
2020-03-02  7:48         ` Christian Brauner

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