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Re: [RESEND-2][PATCH][BZ #13760] Fix dns lookup for AF_UNSPEC whenresponse for T_A exceeds buffer size


On 03/28/2012 12:20 PM, Siddhesh Poyarekar wrote:
On Wed, Mar 28, 2012 at 3:21 PM, Andreas Jaeger<aj@suse.com> wrote:
The current check looks for the ERANGE error in 'errno' when it should
be looking for it in *errnop (where gaih_getanswer_slice sets


The single change for *errnop is ok.

it). Also, we should discard the second response and retry the query
in case of NSS_STATUS_TRYAGAIN and ERANGE (buffer too small) only when
the response error is recoverable. The only condition in which this
currently occurs (buffer too small and h_errno is NO_RECOVERY) is when
the hostname returned by the query is longer than MAXHOSTNAMELEN.


I don't see how this is addressed with your change. Is the patch incomplete
- or what do I miss?


Thanks for the review. The same line has two changes: using *errnop instead of errno and the changed condition, which addresses what I described above:

*h_errnop != NO_RECOVERY
to
*h_errnop == NO_RECOVERY

Indeed, I missed that.


This code is rather confusing. Your analysis and fix looks fine. I suggest to add a short comment before the line you change to explain what is tested.

I guess the missing bz entry in the ChangeLog is for the other patch?

Yes, it was.


Andreas

2012-02-22 Siddhesh Poyarekar<siddhesh@redhat.com>


	[BZ #13760]
	* resolv/nss_dns/dns-host.c (gaih_getanswer): Look for errno
	in the right place. Discard and retry query if response is
	larger than input buffer size.



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