From: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
To: Sergey Bugaev <bugaevc@gmail.com>
Cc: "Cristian Rodríguez" <crrodriguez@opensuse.org>,
libc-alpha@sourceware.org, bug-hurd <bug-hurd@gnu.org>,
"Samuel Thibault" <samuel.thibault@gnu.org>
Subject: Re: [RFC PATCH v2 4/7] csu: Fix standard fds' mode
Date: Thu, 20 Apr 2023 08:47:10 -0300 [thread overview]
Message-ID: <55526044-5046-fafe-319b-bd281e85a2e2@linaro.org> (raw)
In-Reply-To: <CAN9u=HfbJVhcGut5MEVdS6ZT45pEMg4iL9Rb0P47hEYPEkj6Lw@mail.gmail.com>
On 19/04/23 18:16, Sergey Bugaev wrote:
> On Wed, Apr 19, 2023 at 11:45 PM Adhemerval Zanella Netto
>>>> is this really needed now? playing silly games with this fds will always result in silly prices.
>>
>> My understanding of this code is to enforce that on setuid program with
>> stdin/stdout/stderr closed any operation fail.
>
> Yes, but is that still considered desirable / a good idea? As opposed
> to making such operations no-op successfully (opening /dev/null with
> the expected mode).
>
Good question, this is essentially a hardening for setsuid binaries since
opening the file in the *expected* way is not the intended behavior (even
though the C runtime expects that STDIN_FILENO, STDOUT_FILENO, and
STDERR_FILENO are in fact opened). As far I could check, this is really a
glibc extension (both FreeBSD and OpenBSD does not seem to add such
hardening).
I am not really sure how effective is this hardening, it seems more a
development one to enforce that system daemon are spawned correctly.
next prev parent reply other threads:[~2023-04-20 11:47 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-19 16:02 [RFC PATCH v2 0/7] O_IGNORE_CTTY everywhere & misc fixes Sergey Bugaev
2023-04-19 16:02 ` [RFC PATCH v2 1/7] misc: Convert daemon () to GNU coding style Sergey Bugaev
2023-04-21 12:18 ` Adhemerval Zanella Netto
2023-04-22 11:47 ` Samuel Thibault
2023-04-19 16:02 ` [RFC PATCH v2 2/7] misc: Ignore SIGHUP in daemon () while forking Sergey Bugaev
2023-04-21 12:55 ` Adhemerval Zanella Netto
2023-04-19 16:02 ` [RFC PATCH v2 3/7] Use O_CLOEXEC in more places (BZ #15722) Sergey Bugaev
2023-04-21 12:55 ` Adhemerval Zanella Netto
2023-04-22 11:50 ` Samuel Thibault
2023-04-19 16:02 ` [RFC PATCH v2 4/7] csu: Fix standard fds' mode Sergey Bugaev
2023-04-19 19:13 ` Cristian Rodríguez
2023-04-19 19:40 ` Sergey Bugaev
2023-04-19 20:45 ` Adhemerval Zanella Netto
2023-04-19 21:16 ` Sergey Bugaev
2023-04-20 11:47 ` Adhemerval Zanella Netto [this message]
2023-04-20 12:06 ` Cristian Rodríguez
2023-04-20 15:13 ` Adhemerval Zanella Netto
2023-04-21 17:16 ` Paul Eggert
2023-04-19 16:02 ` [RFC PATCH v2 5/7] hurd: Make dl-sysdep's open () cope with O_IGNORE_CTTY Sergey Bugaev
2023-04-20 21:06 ` Samuel Thibault
2023-04-19 16:02 ` [RFC PATCH v2 6/7] include/fcntl.h: Define O_IGNORE_CTTY Sergey Bugaev
2023-04-19 16:02 ` [RFC PATCH v2 7/7] Use O_IGNORE_CTTY where appropriate Sergey Bugaev
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