From: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
To: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, lkml <linux-kernel@vger.kernel.org>,
systemtap <systemtap@sources.redhat.com>,
DLE <dle-develop@lists.sourceforge.net>,
Roland McGrath <roland@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH -tip 2/2] Pass mm->flags as a coredump parameter for consistency
Date: Thu, 19 Nov 2009 21:57:37 +0900 [thread overview]
Message-ID: <4B0540C1.3060605@hitachi.com> (raw)
In-Reply-To: <20091117235401.30900.70697.stgit@dhcp-100-2-132.bos.redhat.com>
Hi Hiramatsu-san,
Masami Hiramatsu wrote:
>> Pass mm->flags as a coredump parameter for consistency.
>>
>> ---
>> 1787 if (mm->core_state || !get_dumpable(mm)) { <- (1)
>> 1788 up_write(&mm->mmap_sem);
>> 1789 put_cred(cred);
>> 1790 goto fail;
>> 1791 }
>> 1792
>> [...]
>> 1798 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ <-(2)
>> 1799 flag = O_EXCL; /* Stop rewrite attacks */
>> 1800 cred->fsuid = 0; /* Dump root private */
>> 1801 }
>> ---
>>
>> Since dumpable bits are not protected by lock, there is a
>> chance to change these bits between (1) and (2).
Yes, a race condition can be caused by prctl from another thread.
And your patch is fine with me. Thanks!
Reviewed-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
--
Hidehiro Kawai
Hitachi, Systems Development Laboratory
Linux Technology Center
next prev parent reply other threads:[~2009-11-19 13:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-17 23:53 [PATCH -tip 0/2] Fix mm->flags consistency issue in coredump Masami Hiramatsu
2009-11-17 23:53 ` [PATCH -tip 1/2] mm: Introduce coredump parameter structure Masami Hiramatsu
2009-11-18 0:19 ` Masami Hiramatsu
2009-11-17 23:54 ` [PATCH -tip 2/2] Pass mm->flags as a coredump parameter for consistency Masami Hiramatsu
2009-11-19 12:57 ` Hidehiro Kawai [this message]
2009-11-19 15:34 ` [PATCH -tip 0/2] Fix mm->flags consistency issue in coredump Américo Wang
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