From: Patrick McHardy <kaber@trash.net>
To: "Maciej Żenczykowski" <zenczykowski@gmail.com>
Cc: Jan Engelhardt <jengelh@medozas.de>, netfilter-devel@vger.kernel.org
Subject: Re: [PATCH 02/17] mark newly opened fds as FD_CLOEXEC (close on exec)
Date: Mon, 04 Apr 2011 14:58:28 +0200 [thread overview]
Message-ID: <4D99C074.5040803@trash.net> (raw)
In-Reply-To: <BANLkTinwDu8MkeoNyHh9e6p1S69DqFEZGQ@mail.gmail.com>
On 01.04.2011 23:34, Maciej Żenczykowski wrote:
>> Redhat still has not given a reason as to why this is needed.
>
> I believe:
> a) the fact CLOEXEC isn't the default on new fd's is a (UNIX/POSIX)
> API bug (which of course can't be fixed...)
> b) not setting CLOEXEC on every fd is an application bug (with the
> exception of the specific few fd's you actually want inherited)
> c) iptables does occasionally fork/exec (to load modules), for
> example "/sbin/modprobe ip6_tables -q", but also for match/target
> revision compatibility checking, and when it does this it can call
> modprobe with additional opened descriptors (for example sockfd inside
> of compatible_revision isn't closed before fork/exec modprobe) - this
> is unclean, and could potentially cause security warnings (or even
> issues?) since iptables and modprobe have different contexts.
>
> [fc14]# ls -alZ `which iptables`
> lrwxrwxrwx. root root system_u:object_r:bin_t:s0 /sbin/iptables
> -> iptables-multi
> [fc14]# ls -alZ /sbin/iptables-multi
> -rwxr-xr-x. root root system_u:object_r:iptables_exec_t:s0 /sbin/iptables-multi
> [fc14]# ls -alZ `which modprobe`
> -rwxr-xr-x. root root system_u:object_r:insmod_exec_t:s0 /sbin/modprobe
>
> I'm not going to claim I fully understand the security implications of
> leaving the file descriptor open across exec, but there is clearly no
> reason to do so, hence the patch.
This seems reasonable to me. Jan, any further objections?
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next prev parent reply other threads:[~2011-04-04 12:58 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-01 4:24 A small series of iptables userspace cleanups Maciej Żenczykowski
2011-04-01 4:27 ` [PATCH 01/17] man pages: allow underscores in match and target names Maciej Żenczykowski
2011-04-04 13:30 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 02/17] mark newly opened fds as FD_CLOEXEC (close on exec) Maciej Żenczykowski
2011-04-01 9:31 ` Jan Engelhardt
2011-04-01 21:34 ` Maciej Żenczykowski
2011-04-04 12:58 ` Patrick McHardy [this message]
2011-04-04 13:00 ` Jan Engelhardt
2011-04-04 13:30 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 03/17] xtables_ip6addr_to_numeric: fix typo in comment Maciej Żenczykowski
2011-04-04 13:31 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 04/17] Delay (statically built) match/target initialization Maciej Żenczykowski
2011-04-04 13:32 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 05/17] v4: rename init_extensions() to init_extensions4() Maciej Żenczykowski
2011-04-01 10:15 ` Jan Engelhardt
2011-04-01 21:38 ` Maciej Żenczykowski
2011-04-04 13:33 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 06/17] v6: rename init_extensions() to init_extensions6() Maciej Żenczykowski
2011-04-04 13:33 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 07/17] xtables.h: init_extensions() no longer exists Maciej Żenczykowski
2011-04-04 13:34 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 08/17] v4: rename for_each_chain() to for_each_chain4() Maciej Żenczykowski
2011-04-04 13:34 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 09/17] v6: rename for_each_chain() to for_each_chain6() Maciej Żenczykowski
2011-04-04 13:35 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 10/17] v4: rename flush_entries() to flush_entries4() Maciej Żenczykowski
2011-04-04 13:35 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 11/17] v6: rename flush_entries() to flush_entries6() Maciej Żenczykowski
2011-04-04 13:36 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 12/17] v4: rename delete_chain() to delete_chain4() Maciej Żenczykowski
2011-04-04 13:36 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 13/17] v6: rename delete_chain() to delete_chain6() Maciej Żenczykowski
2011-04-04 13:37 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 14/17] v4: rename print_rule() to print_rule4() Maciej Żenczykowski
2011-04-04 13:37 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 15/17] v6: rename print_rule() to print_rule6() Maciej Żenczykowski
2011-04-04 13:38 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 16/17] v4: rename do_command() to do_command4() Maciej Żenczykowski
2011-04-04 13:38 ` Patrick McHardy
2011-04-01 4:27 ` [PATCH 17/17] v6: rename do_command() to do_command6() Maciej Żenczykowski
2011-04-04 13:40 ` Patrick McHardy
2011-04-04 19:33 ` Maciej Żenczykowski
2011-04-04 19:48 ` Patrick McHardy
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