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Date:      Thu, 29 Dec 2011 10:44:01 -0800
From:      Xin Li <delphij@delphij.net>
To:        John Baldwin <jhb@freebsd.org>
Cc:        freebsd-security@freebsd.org, Doug Barton <dougb@freebsd.org>, d@delphij.net
Subject:   Re: svn commit: r228843 - head/contrib/telnet/libtelnet head/crypto/heimdal/appl/telnet/libtelnet head/include head/lib/libc/gen head/lib/libc/iconv head/lib/libc/include head/lib/libc/net head/libexec...
Message-ID:  <4EFCB4F1.2050500@delphij.net>
In-Reply-To: <201112291343.02248.jhb@freebsd.org>
References:  <201112231500.pBNF0c0O071712@svn.freebsd.org> <201112290939.53665.jhb@freebsd.org> <4EFCB0C9.6090608@delphij.net> <201112291343.02248.jhb@freebsd.org>

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On 12/29/11 10:43, John Baldwin wrote:
> On Thursday, December 29, 2011 1:26:17 pm Xin Li wrote:
>> On 12/29/11 06:39, John Baldwin wrote:
>>> Can you give some more details on why ftpd is triggering a
>>> dlopen inside of the chroot?  It would appear that that is
>>> unrelated to helper programs (since setting a flag in libc in
>>> ftpd can't possibly affect helper programs ability to use
>>> dlopen() from within libc).
>> 
>> Sure.  That's because nsdispatch(3) would reload
>> /etc/nsswitch.conf if it notices a change.  After chroot() the
>> file is considered as "chang"ed and thus it reloads the file as
>> well as designated shared libraries.
> 
> But ftpd has to be doing some operation that invokes an nss lookup
> after entering the chroot for that to trigger, correct?

Oh ok, that was the built-in ls(1).

Cheers,
- -- 
Xin LI <delphij@delphij.net>	https://www.delphij.net/
FreeBSD - The Power to Serve!		Live free or die
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