Re: BUG #5121: Segmentation Fault when using pam w/ krb5

2009/10/16 Tom Lane <tgl@sss.pgh.pa.us>:
> I wrote:
>> The best idea I can come up with is that the conv_proc is being called
>> with zero messages and is dumping core because it tries to print the
>> contents of msg[0]. =A0However, it's far from clear why libpam would
>> bother to call it with zero messages.
>
> Hah --- found it. =A0(Man, it is so nice working with open source that
> you can actually look at...) =A0prompter.c in pam_krb5 has
>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0/* Skip any prompt for which the supplied =
default answer is the
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 * previously-entered password -- it's jus=
t a waste of the
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 * user's time. =A0*/
>
> So it definitely is possible to call our proc with zero messages, and
> whether this will happen or not is probably dependent on the behavior
> of the KDC, and even then, ereport might or might not dump core depending
> on the contents of the not-allocated msg[0] array member.
>
> I will go and rewrite this function to look more like openssh's,
> on the assumption that their version is probably pretty well battle
> tested.

Yeah, that sounds like a reasonable thing to do.

--=20
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/