[master] fix negative numbers in $GENERATE

3780.	[bug]		$GENERATE handled negative numbers incorrectly.
			[RT #25528]

CHANGES

+3780.	[bug]		$GENERATE handled negative numbers incorrectly. 
+			[RT #25528]
+
 3779.	[cleanup]	Clarify the error message when using an option
 			that was not enabled at compile time. [RT #35504]
 

bin/tests/system/checkzone/zones/bad2.db

+; Copyright (C) 2014  Internet Systems Consortium, Inc. ("ISC")
+;
+; Permission to use, copy, modify, and/or distribute this software for any
+; purpose with or without fee is hereby granted, provided that the above
+; copyright notice and this permission notice appear in all copies.
+;
+; THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+; REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+; AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+; INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+; LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+; OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+; PERFORMANCE OF THIS SOFTWARE.
+
+$TTL 600
+@		SOA	ns hostmaster 2011012708 3600 1200 604800 1200
+		NS	ns
+ns		A	192.0.2.1
+
+; The following GENERATE directive contains two dashes in the range
+; which is a syntax error.
+$GENERATE 9--10 host$ 3600 A 192.0.2.$

doc/arm/Bv9ARM-book.xml

@@ -14205,8 +14205,9 @@ HOST-127.EXAMPLE. MX 0 .
 		    <para>
 		      This can be one of two forms: start-stop
 		      or start-stop/step. If the first form is used, then step
-		      is set to
-		      1. All of start, stop and step must be positive.
+		      is set to 1. start, stop and step must be positive
+		      integers between 0 and (2^31)-1. start must not be
+		      larger than stop.
 		    </para>
 		  </entry>
 		</row>

lib/dns/master.c

@@ -806,7 +806,7 @@ generate(dns_loadctx_t *lctx, char *range, char *lhs, char *gtype, char *rhs,
 	isc_buffer_t target;
 	isc_result_t result;
 	isc_textregion_t r;
-	unsigned int start, stop, step, i;
+	int start, stop, step, i;
 	dns_incctx_t *ictx;
 
 	ictx = lctx->inc;
@@ -824,8 +824,10 @@ generate(dns_loadctx_t *lctx, char *range, char *lhs, char *gtype, char *rhs,
 	}
 	isc_buffer_init(&target, target_mem, target_size);
 
-	n = sscanf(range, "%u-%u/%u", &start, &stop, &step);
-	if (n < 2 || stop < start) {
+	n = sscanf(range, "%d-%d/%d", &start, &stop, &step);
+	if ((n < 2) || (start < 0) || (stop < 0) || (step < 0) ||
+	    (stop < start))
+	{
 	       (*callbacks->error)(callbacks,
 				  "%s: %s:%lu: invalid range '%s'",
 				  "$GENERATE", source, line, range);