From: Thomas Gleixner <tglx@linutronix.de>
To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Sasha Levin <sasha.levin@oracle.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] posix-timer: don't call idr_find() w/ out-of-range ID
Date: Thu, 21 Feb 2013 00:01:07 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.02.1302202358220.22263@ionos> (raw)
In-Reply-To: <20130220224019.GI3570@htj.dyndns.org>
On Wed, 20 Feb 2013, Tejun Heo wrote:
> When idr_find() is fed a negative ID, it used to look up the ID
> ignoring the sign bit before recent ("idr: remove MAX_IDR_MASK and
> move left MAX_IDR_* into idr.c") patch, and triggers WARN_ON_ONCE()
> after it.
>
> __lock_timer() feeds timer_id from userland directly to idr_find()
> without sanitizing it which can trigger the above malfunctions. Add a
> range check on @timer_id before invoking idr_find() in __lock_timer().
>
> While timer_t is defined as int by all archs at the moment, Andrew
> worries that it may be defined as a larger type later on. Make the
> test cover larger integers too so that it at least is guaranteed to
> not return the wrong timer.
Again. I totaly agree with that for stable, but I disagree that this
is the real fix.
idr_find() should simply return NULL, if "id < 0". Is it that hard?
Thanks,
tglx
next prev parent reply other threads:[~2013-02-20 23:01 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-20 18:44 [PATCH] idr: prevent NULL deref on lookups before insertions Sasha Levin
2013-02-20 18:45 ` Tejun Heo
2013-02-20 19:23 ` Sasha Levin
2013-02-20 21:01 ` [PATCH] posix-timer: don't call idr_find() w/ negative ID Tejun Heo
2013-02-20 21:23 ` Andrew Morton
2013-02-20 21:37 ` Tejun Heo
2013-02-20 22:05 ` Andrew Morton
2013-02-20 22:08 ` Tejun Heo
2013-02-20 22:40 ` [PATCH] posix-timer: don't call idr_find() w/ out-of-range ID Tejun Heo
2013-02-20 23:01 ` Thomas Gleixner [this message]
2013-02-20 23:07 ` Tejun Heo
2013-02-20 23:11 ` Thomas Gleixner
2013-02-20 23:24 ` [PATCH UPDATED] " Tejun Heo
2013-02-20 23:35 ` [PATCH] idr: explain WARN_ON_ONCE() on negative IDs " Tejun Heo
2013-02-21 9:10 ` Thomas Gleixner
2013-02-21 16:38 ` [tip:timers/urgent] posix-timer: Don't call idr_find() with " tip-bot for Tejun Heo
2013-02-20 22:10 ` [PATCH] posix-timer: don't call idr_find() w/ negative ID Sasha Levin
2013-02-20 22:12 ` Tejun Heo
2013-02-20 22:15 ` Sasha Levin
2013-02-20 22:20 ` Tejun Heo
2013-02-20 23:09 ` Thomas Gleixner
2013-02-20 21:32 ` Sasha Levin
2013-02-20 21:38 ` Thomas Gleixner
2013-02-20 21:43 ` Tejun Heo
2013-02-20 21:47 ` Thomas Gleixner
2013-02-20 21:50 ` Tejun Heo
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