Fix assertion failures in resolver (BZ #13013).

	[BZ #13013]
	* resolv/res_query.c(__libc_res_nquery): Assign hp and hp2
	depending n and resplen2 to catch cases where answer
	equals answerp2.

1 files changed, 15 insertions, 15 deletions

diff --git a/resolv/res_query.c b/resolv/res_query.c
index abccd4a..1325f97 100644
--- a/resolv/res_query.c
+++ b/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