svn commit: r265003 - head/secure/usr.sbin/sshd

[Roger Pau Monné]

On 20/08/14 17:13, Konstantin Belousov wrote:
> On Wed, Aug 20, 2014 at 04:41:05PM +0200, Roger Pau Monn?? wrote:
>> On 27/04/14 07:28, Konstantin Belousov wrote:
>>> Author: kib
>>> Date: Sun Apr 27 05:28:14 2014
>>> New Revision: 265003
>>> URL: http://svnweb.freebsd.org/changeset/base/265003
>>>
>>> Log:
>>>   Fix order of libthr and libc in the global dso list for sshd, by
>>>   explicitely linking main binary with -lpthread.  Before, libthr
>>>   appeared in the list due to dependency of one of the kerberos libs.
>>>   Due to the change in ld(1) behaviour of not copying NEEDED entries
>>>   from direct dependencies into the link results, the order becomes
>>>   reversed.
>>>   
>>>   The libthr must appear before libc to properly interpose libc symbols
>>>   and provide working rtld locks implementation.  The symptom was sshd
>>>   hanging on rtld bind lock during nested symbol binding from a signal
>>>   handler.
>>>   
>>>   Approved by:	des (openssh maintainer)
>>>   Sponsored by:	The FreeBSD Foundation
>>>   MFC after:	1 week
>>>
>>> Modified:
>>>   head/secure/usr.sbin/sshd/Makefile
>>>
>>> Modified: head/secure/usr.sbin/sshd/Makefile
>>> ==============================================================================
>>> --- head/secure/usr.sbin/sshd/Makefile	Sun Apr 27 05:19:01 2014	(r265002)
>>> +++ head/secure/usr.sbin/sshd/Makefile	Sun Apr 27 05:28:14 2014	(r265003)
>>> @@ -57,6 +57,16 @@ CFLAGS+= -DNONE_CIPHER_ENABLED
>>>  DPADD+= ${LIBCRYPT} ${LIBCRYPTO} ${LIBZ}
>>>  LDADD+= -lcrypt -lcrypto -lz
>>>  
>>> +# Fix the order of NEEDED entries for libthr and libc. The libthr
>>> +# needs to interpose libc symbols, leaving the libthr loading as
>>> +# dependency of krb causes reversed order and broken interposing. Put
>>> +# the threading library last on the linker command line, just before
>>> +# the -lc added by a compiler driver.
>>> +.if ${MK_KERBEROS_SUPPORT} != "no"
>>> +DPADD+= ${LIBPTHREAD}
>>> +LDADD+= -lpthread
>>> +.endif
>>> +
>>>  .if defined(LOCALBASE)
>>>  CFLAGS+= -DXAUTH_PATH=\"${LOCALBASE}/bin/xauth\"
>>>  .endif
>>
>> Hello,
>>
>> This change makes the following simple test program fail on the second 
>> assert. The problem is that sa_handler == SIG_DFL, and sa_flags == 
>> SA_SIGINFO, which according to the sigaction(9) man page is not 
>> possible. With this change reverted the test is successful.
> I do not quite follow.
> 
> What are the relations between sshd and your test program ?
> Should the test be run somehow specially ?

No, and frankly that's what I don't understand. I compile this simple
test with `cc -o test test.c`. It fails with this commit applied, and
succeeds without it.

Roger.