From: Jiri Kosina <jikos@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: tip-bot for Michal Hocko <tipbot@zytor.com>,
linux-tip-commits@vger.kernel.org, torvalds@linux-foundation.org,
mingo@kernel.org, hpa@zytor.com, mhocko@suse.com,
tglx@linutronix.de, davej@codemonkey.org.uk,
peterz@infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [tip:x86/mm] x86/mmap, ASLR: Do not treat unlimited-stack tasks as legacy mmap
Date: Tue, 27 Jun 2017 10:00:23 +0200 (CEST) [thread overview]
Message-ID: <alpine.LSU.2.20.1706270958520.30709@cbobk.fhfr.pm> (raw)
In-Reply-To: <20170623145441.GB9388@redhat.com>
On Fri, 23 Jun 2017, Oleg Nesterov wrote:
> > We added a heuristics to treat applications with RLIMIT_STACK configured
> > to unlimited as legacy. This means:
>
> To me this also means a minor security problem. The comment above
> PER_CLEAR_ON_SETID says "must be cleared upon setuid or setgid exec",
> but if you do "ulimit -s unlimited" before suid exec then
> ADDR_COMPAT_LAYOUT set by security checks will be ignored.
Could you please be a bit more specific here?
mmap_is_legacy() *first* checks for the ADDR_COMPAT_LAYOUT in the
personality flags, and only then, if it's unset, RLIMIT_STACK comes to
play.
Thanks,
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2017-06-27 8:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-14 8:22 [RFC PATCH] mmap, aslr: do not enforce legacy mmap on unlimited stacks Michal Hocko
2017-06-23 8:46 ` Michal Hocko
2017-06-23 14:02 ` [tip:x86/mm] x86/mmap, ASLR: Do not treat unlimited-stack tasks as legacy mmap tip-bot for Michal Hocko
2017-06-23 14:54 ` Oleg Nesterov
2017-06-27 8:00 ` Jiri Kosina [this message]
2017-06-27 14:22 ` Oleg Nesterov
2017-06-28 9:40 ` Jiri Kosina
2017-06-23 20:35 ` Jiri Kosina
2017-06-24 6:43 ` tip-bot for Michal Hocko
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