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From: David Wuertele <dave+gmane@wuertele.com>
To: musl@lists.openwall.com
Subject: Re: NULL deref SEGV in malloc.c:unbin()
Date: Mon, 30 Dec 2013 19:17:49 +0000 (UTC)	[thread overview]
Message-ID: <loom.20131230T200524-937@post.gmane.org> (raw)
In-Reply-To: <20131229000112.GY1685@port70.net>

I found the root cause of the SEGV, I was calling closedir() on the
same dir pointer twice (quite some time before the SEGV).

I assume that the behavior of closedir() is undefined when used this
way, so my program now makes sure not to do that.

But it seems a poor implementation that a double call to closedir
should result in memory corruption, and it seems a bug in malloc()
that a closedir/opendir sequence can cause it to SEGV.

I tried to reduce my program to just this behavior so that I could
give you a test case, but the SEGV did not occur with just the
opendir/closedir sequence my program calls.

Dave




  parent reply	other threads:[~2013-12-30 19:17 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-27 18:35 David Wuertele
2013-12-27 19:05 ` Rich Felker
2013-12-27 19:44   ` David Wuertele
2013-12-27 22:13     ` Rich Felker
2013-12-28  0:25       ` David Wuertele
2013-12-28  1:28         ` David Wuertele
2013-12-28  3:03           ` Rich Felker
2013-12-29  0:01           ` Szabolcs Nagy
2013-12-29  0:05             ` Szabolcs Nagy
2013-12-29  1:34               ` Rich Felker
2013-12-30 19:17             ` David Wuertele [this message]
2013-12-30 21:25               ` Rich Felker

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