Strange segmentation fault in libkrb5.so.3.3 (1.6.4-beta1)

[Dan Searle]

Hi,

Just a heads up, to work around the issue, I had to change:

kerrs.c:87:

    return krb5int_get_error (&ctx->err, code);

...to...

    return NULL;



Dan Searle wrote:
> Hi,
>
> Ok, authenticating a user against a Windows 2008R2 KDC with an expired 
> passwords is a 100% sure way of recreating this error. I've recreated 
> the error using an Ubuntu source package to compile version 
> krb5-1.6.dfsg.3~beta1 from sources with debug symbols, and here's the 
> gdb stack trace I get:
>
> #0  0xb7f9838b in ?? () from /lib/ld-linux.so.2
> #1  0xb7f9dc80 in ?? () from /lib/ld-linux.so.2
> #2  0xb70c087d in krb5_get_error_message (ctx=0x8220428, 
> code=-1765328324) at ../../../../src/lib/krb5/krb/kerrs.c:87
> #3  0x7de66ec4 in ?? () from /lib/security/pam_krb5.so
> #4  0x7de6745f in ?? () from /lib/security/pam_krb5.so
> #5  0x7de6623a in ?? () from /lib/security/pam_krb5.so
> #6  0x7de640be in pam_sm_authenticate () from /lib/security/pam_krb5.so
> #7  0xb7df51c8 in ?? () from /lib/libpam.so.0
> #8  0xb7df4a8d in pam_authenticate () from /lib/libpam.so.0
> [snip]
>
> kerrs.c:87 corresponds to the following call:
>
>     return krb5int_get_error (&ctx->err, code);
>
> krb5int_get_error is an exported symbol in the libkrb5support library, 
> so what's going on with ld? Is it failing to find the symbol?
>
> For now I'm just going to make krb5_get_error_message return 
> error_message(code); rather than the context based krb5int_get_error, as 
> I'm not bothered about the message it's self.
>
> Regards, Dan...
>
> Russ Allbery wrote:
>   
>> Greg Hudson <ghudson at MIT.EDU> writes:
>>
>>   
>>     
>>> I suspect this is:
>>>     
>>>       
>>   
>>     
>>> http://krbdev.mit.edu/rt/Ticket/Display.html?id=6681&user=guest&pass=guest
>>>     
>>>       
>>   
>>     
>>> which should be fixed in the forthcoming krb5 1.8.1.
>>>     
>>>       
>>   
>>     
>>> If I'm correct, the pam_krb5 code could work around the bug, but I'm not
>>> sure if there's a configuration workaround.
>>>     
>>>       
>> After further investigation, I don't believe that's the problem here.
>> pam-krb5 never calls krb5_get_init_creds_password with a NULL options
>> argument.  (And Dan's backtrace shows that the options argument is not
>> NULL.)
>>
>>   
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - www.avg.com 
>> Version: 9.0.791 / Virus Database: 271.1.1/2782 - Release Date: 03/31/10 19:32:00
>>
>>   
>>     
>
>
>   
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com 
> Version: 9.0.791 / Virus Database: 271.1.1/2797 - Release Date: 04/07/10 19:32:00
>
>   


-- 
Dan Searle

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