From: Roland McGrath <roland@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Brad Spengler <spender@grsecurity.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, oss-security@lists.openwall.com,
Solar Designer <solar@openwall.com>,
Kees Cook <kees.cook@canonical.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Oleg Nesterov <oleg@redhat.com>,
Neil Horman <nhorman@tuxdriver.com>,
linux-fsdevel@vger.kernel.org, pageexec@freemail.hu,
Brad Spengler <spender@grsecurity.net>,
Eugene Teo <eugene@redhat.com>
Subject: Re: [PATCH 1/3] setup_arg_pages: diagnose excessive argument size
Date: Fri, 10 Sep 2010 02:25:41 -0700 (PDT) [thread overview]
Message-ID: <20100910092541.2864A405D5@magilla.sf.frob.com> (raw)
In-Reply-To: KOSAKI Motohiro's message of Thursday, 9 September 2010 14:31:18 +0900 <20100909141534.C948.A69D9226@jp.fujitsu.com>
> Brad, sorry, I have bad news. glibc sysconf(_SC_ARG_MAX) is implemented
> by hard coded RLIMIT_STACK/4 heuristics. That said, at least _now_, we
> can't change this even though you disliked. That said, we can't break
> userland even though userland library is very crazy.
I'm sorry you think it's "very crazy" to implement the required
functionality in the only way available. POSIX requires that execve
fail with E2BIG when the ARG_MAX limit is exceeded. sysconf has to
return the correct actual limit that execve will enforce so that a
conforming application knows how much it can safely attempt to use.
Since the kernel uses the hard-coded RLIMIT_STACK/4 heuristic and does
not expose the true manifest limit any other way, sysconf has to
parallel the kernel's calculation.
Thanks,
Roland
next prev parent reply other threads:[~2010-09-10 9:27 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-27 22:02 [PATCH] exec argument expansion can inappropriately trigger OOM-killer Kees Cook
2010-08-30 0:19 ` KOSAKI Motohiro
2010-08-30 0:56 ` Roland McGrath
2010-08-30 3:23 ` Solar Designer
2010-08-30 10:06 ` Roland McGrath
2010-08-30 19:48 ` Solar Designer
2010-08-31 0:40 ` Roland McGrath
2010-09-08 2:34 ` [PATCH 0/3] execve argument-copying fixes Roland McGrath
2010-09-08 2:35 ` [PATCH 1/3] setup_arg_pages: diagnose excessive argument size Roland McGrath
2010-09-08 8:29 ` pageexec
2010-09-10 8:59 ` Roland McGrath
2010-09-11 13:30 ` pageexec
2010-09-14 19:33 ` Roland McGrath
2010-09-14 22:35 ` pageexec
2010-09-08 11:57 ` Brad Spengler
2010-09-09 5:31 ` KOSAKI Motohiro
2010-09-10 9:25 ` Roland McGrath [this message]
2010-09-10 9:43 ` KOSAKI Motohiro
2010-09-11 13:39 ` pageexec
2010-09-14 18:51 ` Roland McGrath
2010-09-14 20:28 ` pageexec
2010-09-14 21:16 ` Roland McGrath
2010-09-14 22:27 ` pageexec
2010-09-14 23:04 ` Roland McGrath
2010-09-15 9:27 ` pageexec
2010-09-10 9:18 ` Roland McGrath
2010-09-08 2:36 ` [PATCH 2/3] execve: improve interactivity with large arguments Roland McGrath
2010-09-08 2:37 ` [PATCH 3/3] execve: make responsive to SIGKILL " Roland McGrath
2010-09-08 3:00 ` [PATCH 0/3] execve argument-copying fixes KOSAKI Motohiro
2010-09-09 5:01 ` [PATCH 0/2] execve memory exhaust of " KOSAKI Motohiro
2010-09-09 5:03 ` [PATCH 1/2] oom: don't ignore rss in nascent mm KOSAKI Motohiro
2010-09-09 22:05 ` Oleg Nesterov
2010-09-10 9:39 ` Roland McGrath
2010-09-10 9:57 ` [PATCH] move cred_guard_mutex from task_struct to signal_struct KOSAKI Motohiro
2010-09-10 17:24 ` Oleg Nesterov
2010-09-16 5:51 ` KOSAKI Motohiro
2010-09-09 5:04 ` [PATCH 2/2] execve: check the VM has enough memory at first KOSAKI Motohiro
2010-09-10 15:06 ` Linus Torvalds
2010-09-14 1:52 ` KOSAKI Motohiro
2010-09-16 5:51 ` KOSAKI Motohiro
2010-09-16 15:01 ` Linus Torvalds
2010-08-30 17:49 ` [PATCH] exec argument expansion can inappropriately trigger OOM-killer Solar Designer
2010-08-30 22:08 ` Brad Spengler
2010-08-31 11:53 ` Solar Designer
2010-08-31 11:56 ` [PATCH] exec argument expansion can inappropriately triggerOOM-killer Tetsuo Handa
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