From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>,
Alexander Viro <viro@zeniv.linux.org.uk>,
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"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [RFC][PATCH] exec: Move cred computation under exec_update_lock
Date: Sun, 23 Nov 2025 19:52:20 +0100 [thread overview]
Message-ID: <aSNX5B9a5iSjJcM1@redhat.com> (raw)
In-Reply-To: <87h5uoxw06.fsf_-_@email.froward.int.ebiederm.org>
Eric,
sorry for delay, I am on PTO, didn't read emails this week...
On 11/20, Eric W. Biederman wrote:
>
> Instead of computing the new cred before we pass the point of no
> return compute the new cred just before we use it.
>
> This allows the removal of fs_struct->in_exec and cred_guard_mutex.
>
> I am not certain why we wanted to compute the cred for the new
> executable so early. Perhaps I missed something but I did not see any
> common errors being signaled. So I don't think we loose anything by
> computing the new cred later.
>
> We gain a lot.
Yes. I LIKE your approach after a quick glance. And I swear, I thought about
it too ;)
But is it correct? I don't know. I'll try to actually read your patch next
week (I am on PTO untill the end of November), but I am not sure I can
provide a valuable feedback.
One "obvious" problem is that, after this patch, the execing process can crash
in a case when currently exec() returns an error...
Oleg.
next prev parent reply other threads:[~2025-11-23 18:52 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 12:23 [PATCH v10] exec: Fix dead-lock in de_thread with ptrace_attach Bernd Edlinger
2021-07-11 17:43 ` [PATCH v11] " Bernd Edlinger
2023-10-30 5:20 ` [PATCH v12] " Bernd Edlinger
2023-10-30 9:00 ` kernel test robot
2023-11-06 6:41 ` [PATCH v13] " Bernd Edlinger
2024-01-15 19:22 ` [PATCH v14] " Bernd Edlinger
2024-01-15 19:37 ` Matthew Wilcox
2024-01-17 9:51 ` Bernd Edlinger
2024-01-16 15:22 ` Oleg Nesterov
2024-01-17 15:07 ` Bernd Edlinger
2024-01-17 16:38 ` Oleg Nesterov
2024-01-22 13:24 ` Bernd Edlinger
2024-01-22 13:44 ` Oleg Nesterov
2024-01-22 21:30 ` Kees Cook
2024-01-23 18:30 ` Bernd Edlinger
2024-01-24 0:09 ` Kees Cook
2024-01-22 18:31 ` [PATCH v15] " Bernd Edlinger
2025-08-18 6:04 ` Jain, Ayush
2025-08-18 20:53 ` [PATCH v16] " Bernd Edlinger
2025-08-19 4:36 ` Kees Cook
2025-08-19 18:53 ` Bernd Edlinger
2025-08-21 17:34 ` [PATCH v17] " Bernd Edlinger
2025-10-27 6:26 ` Bernd Edlinger
2025-10-27 12:06 ` Peter Zijlstra
2025-11-02 16:17 ` Oleg Nesterov
2025-11-05 14:32 ` Oleg Nesterov
2025-11-11 9:21 ` Christian Brauner
2025-11-11 11:07 ` Bernd Edlinger
2025-11-11 13:12 ` Oleg Nesterov
2025-11-11 13:45 ` Bernd Edlinger
2025-11-12 9:52 ` Oleg Nesterov
2025-11-17 6:31 ` Bernd Edlinger
2025-11-17 15:01 ` Oleg Nesterov
2025-11-17 20:08 ` Bernd Edlinger
2025-11-23 18:32 ` Oleg Nesterov
2025-11-29 15:06 ` Bernd Edlinger
2025-12-01 15:13 ` Oleg Nesterov
2025-11-09 17:14 ` [RFC PATCH 0/3] mt-exec: fix deadlock with ptrace_attach() Oleg Nesterov
2025-11-09 17:14 ` [RFC PATCH 1/3] exec: make setup_new_exec() return int Oleg Nesterov
2025-11-09 17:15 ` [RFC PATCH 2/3] exec: don't wait for zombie threads with cred_guard_mutex held Oleg Nesterov
2025-11-10 10:58 ` Cyrill Gorcunov
2025-11-10 15:09 ` Oleg Nesterov
2025-11-10 21:49 ` Cyrill Gorcunov
2025-11-11 14:09 ` Oleg Nesterov
2025-11-09 17:16 ` [RFC PATCH 3/3] ptrace: ensure PTRACE_EVENT_EXIT won't stop if the tracee is killed by exec Oleg Nesterov
2025-11-10 5:28 ` [RFC PATCH 0/3] mt-exec: fix deadlock with ptrace_attach() Bernd Edlinger
2025-11-10 14:47 ` Oleg Nesterov
2025-11-18 18:13 ` [PATCH v18] exec: Fix dead-lock in de_thread with ptrace_attach Bernd Edlinger
2025-11-20 15:15 ` Eric W. Biederman
2025-11-20 17:29 ` Eric W. Biederman
2025-11-20 20:57 ` [RFC][PATCH] exec: Move cred computation under exec_update_lock Eric W. Biederman
2025-11-20 23:50 ` Eric W. Biederman
2025-11-21 2:59 ` Bernd Edlinger
2025-11-21 7:18 ` Eric W. Biederman
2025-11-21 9:35 ` Bernd Edlinger
2025-11-21 11:26 ` Bernd Edlinger
2025-11-21 19:19 ` Eric W. Biederman
2025-11-21 23:06 ` Ryan Lee
2025-11-23 18:52 ` Oleg Nesterov [this message]
2025-11-23 23:22 ` Eric W. Biederman
2025-11-25 16:19 ` Bernd Edlinger
2025-11-25 11:55 ` Roberto Sassu
2025-12-01 16:06 ` Are setuid shell scripts safe? (Implied by security_bprm_creds_for_exec) Eric W. Biederman
2025-12-01 16:49 ` Roberto Sassu
2025-12-01 18:53 ` Eric W. Biederman
2025-12-01 21:39 ` David Laight
2025-12-03 13:16 ` Bernd Edlinger
2025-12-04 5:49 ` Al Viro
2025-12-04 9:32 ` David Laight
2025-12-04 13:03 ` Bernd Edlinger
2025-12-09 12:28 ` Jan Kara
2025-12-04 15:43 ` Stephen Smalley
2025-11-22 17:10 ` [PATCH v18] exec: Fix dead-lock in de_thread with ptrace_attach Bernd Edlinger
2025-12-19 8:15 ` [PATCH v19] " Bernd Edlinger
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