bind4.8 under OSx4.1: fix

[Curtis Generous]

Subject: named4.8 core dumps with a `bus error`
Index:	 /usr/src/etc/bind4.8/named/ns_resp.c

Description:
	A pointer is getting corrupted in a segment of code.
	The source of the problem appears to be a compiler generated,
	although I have not had a chance to dig in the 
	generated assembler code generated by both code segments.  
	This problem was discovered on a 98x running OSx4.1-880727.

Repeat-By:
	Run named in debug mode, and watch for calls to make_rr()
	where buflen value is some absurd number (i.e. -178372742 -- more
	like an address than a length value).

Fix:
	Apply the simple patch below.  All this does is rewrite the code
	section where the pointer cp was getting trashed (note: the
	`replacement` code I provided was mostly extracted from an earlier
	version of named (version 4.3) that ran without problems under
	OSx4.1).

*** /tmp/,RCSt1026998	Sat Nov 19 08:32:22 1988
--- ns_resp.c	Fri Nov 18 10:17:06 1988
***************
*** 473,480
  #endif
  		goto servfail;
  	}
! 	cp = newmsg + sizeof(HEADER) +
! 	    (cname ? dn_skipname(cp, newmsg + newmsglen) : n) + QFIXEDSZ;
  	buflen = sizeof(newmsg) - (cp - newmsg);
  
  try_again:

--- 473,484 -----
  #endif
  		goto servfail;
  	}
! 	cp = newmsg + sizeof(HEADER);
! 	if (cname)
! 		cp += dn_skipname(cp, newmsg + newmsglen);
! 	else
! 		cp += n;
! 	cp += QFIXEDSZ;
  	buflen = sizeof(newmsg) - (cp - newmsg);
  
  try_again:
-- 
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