8.0 Dynamic Linker Broken? (Was: [PATCH] SASL problems with spnego on 8.0-BETA4)

[Alexander Nedotsukov]

Doug,

I share your concerns about wrong libgssapi_foo usage.
Do you see any possible drawbacks of:
3) Move libgssapi_foo into gssapi/libfoo_mech and link libgoo_mech  
against libgssapi

Thanks,
Alexander

On 05.10.2009, at 16:29, Doug Rabson wrote:

> This is the core of the problem, I think. There are two possible  
> solutions:
>
> 1. Link libgssapi_foo.so against libgssapi.so. I'm not a fan of this  
> because it will encourage people to link with libgssapi_krb5.so when  
> they really ought to be linking with libgssapi.so to give them  
> mechanism independance.
>
> 2. Split the various mechanism libs in to two parts, mech_foo.so  
> which will contain the actual mechanism implementation (this can  
> link with libgssapi.so to handle the RTLD_LOCAL issue) and  
> optionally libgssapi_foo.so to contain any mechanism-specific  
> extensions.
>
> Clearly (2) is unsuitable for 8.0 but could happen in current. I  
> guess we could use (1) as a band-aid fix for 8.0.
>
> On 5 Oct 2009, at 05:50, Alexander Nedotsukov wrote:
>
>>
>> Actually this may mean quite otherwise.
>> What I saying is if some code (eg. libsasl) dlopen() libgssapi as
>> RTLD_LOCAL then later attempt to load libgssapi_xxx inside  
>> libgssapi may
>> fail because of this:
>>
>> $ldd /usr/lib/libgssapi_spnego.so
>> /usr/lib/libgssapi_spnego.so:
>>       libasn1.so.10 => /usr/lib/libasn1.so.10 (0x28300000)
>>       libc.so.7 => /lib/libc.so.7 (0x2808f000)
>>
>> I would expect to see libgssapi.so.10 dependency here.
>>
>> On Mon, 5 Oct 2009 10:07:20 +1100, John Marshall
>> <john.marshall at riverwillow.com.au> wrote:
>>> On Fri, 02 Oct 2009, 08:24 -0400, John Baldwin wrote:
>>>> On Friday 02 October 2009 4:13:19 am John Marshall wrote:
>>>>> On Tue, 22 Sep 2009, 08:22 +1000, John Marshall wrote:
>>>>>> On Mon, 21 Sep 2009, 11:26 -0400, Rick Macklem wrote:
>>>>>>
>>> [snip]
>>>>>>>
>>>>>>> Now, hopefully someone who understands enough about dynamic
>>>>>>> linking will
>>>>>>> know if this is the correct fix for 8.0? (I'm going on a couple
>> of
>>>>>>> weeks
>>>>>>> vacation at the end of this week, so I won't be around to commit
>>>>>>> anything
>>>>>>> and don't understand it well enough to know if this is the
>> correct
>>>>>>> way
>>>>>>> to fix it.)
>>>>>>>
>>>>>>> So, hopefully someone else can pick this one up?
>>>>>>>
>>> [snip]
>>>>>>
>>>>>> I have submitted a patch to the FreeBSD Makefile which patches  
>>>>>> the
>>>>>> vendor-supplied template for krb5-config.  I should be grateful  
>>>>>> if
>>>>>> dfr@
>>>>>> or another src committer would please review this with a view to
>>>>>> obtaining re@ approval to commit it before 8.0-RC2.
>>>>>>
>>>>>> <http://www.freebsd.org/cgi/query-pr.cgi?pr=139037>
>>>>>
>>>>> Any src committers able to help with this?
>>>>
>>>> Hmmm, I thought that libgssapi was supposed to use dlopen to load  
>>>> the
>>>> proper
>>>> back-end libraries using /etc/gss/mech rather than having  
>>>> applications
>>>> directly link against them.
>>>
>>> OK, so if my proposed solution is, in fact, only masking a symptom  
>>> of a
>>> broken dynamic linker, would somebody who understands this stuff  
>>> please
>>> weigh in on this with some debugging suggestions or with a patch to
>>> address this problem?
>>>
>>> I'm able to help with testing but I'm not a programmer and know  
>>> nothing
>>> about the FreeBSD dynamic linker.
>>>
>>> Thanks.
>
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