Strange segmentation fault in (1.6.4-beta1)

Dan Searle dan.searle at
Thu Apr 8 08:28:19 EDT 2010


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/
#1  0xb7f9dc80 in ?? () from /lib/
#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/
#4  0x7de6745f in ?? () from /lib/security/
#5  0x7de6623a in ?? () from /lib/security/
#6  0x7de640be in pam_sm_authenticate () from /lib/security/
#7  0xb7df51c8 in ?? () from /lib/
#8  0xb7df4a8d in pam_authenticate () from /lib/

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:
>> 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.)
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Dan Searle

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