Submitted By:            Bruce Dubbs <bdubbs_at_linuxfromscratch_dot_org>
Date:                    2012-08-27
Initial Package Version: 2.16.0
Upstream Status:         Not yet applied, but in other distros.
Origin:                  http://sourceware.org/bugzilla/attachment.cgi?id=5855
Description:             Fixes a problem with name resolution with errors
                         from some name servers.

--- a/resolv/res_query.c
+++ a/resolv/res_query.c
@@ -122,6 +122,7 @@ __libc_res_nquery(res_state statp,
		  int *resplen2)
 {
	HEADER *hp = (HEADER *) answer;
+	HEADER *hp2;
	int n, use_malloc = 0;
	u_int oflags = statp->_flags;

@@ -239,26 +240,25 @@ __libc_res_nquery(res_state statp,
	  /* __libc_res_nsend might have reallocated the buffer.  */
	  hp = (HEADER *) *answerp;

-	/* We simplify the following tests by assigning HP to HP2.  It
-	   is easy to verify that this is the same as ignoring all
-	   tests of HP2.  */
-	HEADER *hp2 = answerp2 ? (HEADER *) *answerp2 : hp;
-
-	if (n < (int) sizeof (HEADER) && answerp2 != NULL
-	    && *resplen2 > (int) sizeof (HEADER))
+	/* We simplify the following tests by assigning HP to HP2 or
+	   vice versa.  It is easy to verify that this is the same as
+	   ignoring all tests of HP or HP2.  */
+	if (answerp2 == NULL || *resplen2 < (int) sizeof (HEADER))
	  {
-	    /* Special case of partial answer.  */
-	    assert (hp != hp2);
-	    hp = hp2;
+	    hp2 = hp;
	  }
-	else if (answerp2 != NULL && *resplen2 < (int) sizeof (HEADER)
-		 && n > (int) sizeof (HEADER))
+	else
	  {
-	    /* Special case of partial answer.  */
-	    assert (hp != hp2);
-	    hp2 = hp;
+	    hp2 = (HEADER *) *answerp2;
+	    if (n < (int) sizeof (HEADER))
+	      {
+	        hp = hp2;
+	      }
	  }

+	/* Make sure both hp and hp2 are defined */
+	assert((hp != NULL) && (hp2 != NULL));
+
	if ((hp->rcode != NOERROR || ntohs(hp->ancount) == 0)
	    && (hp2->rcode != NOERROR || ntohs(hp2->ancount) == 0)) {
 #ifdef DEBUG