apparent bug in 7/26/06 version of 'tzload()'

[Olson, Arthur David (NIH/NCI) [E]]

David's analysis and fix look good to me; I plan to incorporate the fix
in the next time zone bundle.

Now if only C had an &&= operator...

				--ado 

-----Original Message-----
From: Olson, Arthur David (NIH/NCI) [E] 
Sent: Thursday, July 27, 2006 2:20 PM
To: tz at lecserver.nci.nih.gov
Cc: lawless at spamcop.net
Subject: FW: apparent bug in 7/26/06 version of 'tzload()'

David Lawless is not on the time zone mailing list; direct replies
appropriately. 

-----Original Message-----
From: David Lawless [mailto:lawless at spamcop.net]
Sent: Thursday, July 27, 2006 2:04 PM
To: tz at lecserver.nci.nih.gov
Subject: apparent bug in 7/26/06 version of 'tzload()'

While experimenting with 'localhost.c' I discovered a bug in
'localtime.c' in 'tzload()'.  The last few lines setup two flags
'goback' and 'goahead'.  This code executes some invalid negative-offset
array dereferences when the number of points in the array is too small.
RHEL4.3 (CentOS 4.3) has zone files with fewer than 800 years in them
and provokes this.

I believe the attached patch corrects the problem.  However I don't
understand the purpose of the code and may have got it wrong.

Please CC my e-mail with any replies as I'm not on the mailing list.

Regards,

David Lawless