busybox: add upstream fixes for 1.25.0

Add upstream patches to fix gzip (bug #9131 - incorrect compression
levels), ip (route add bug) and ntpd (CVE-2016-6301 - NTP server denial
of service).

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/busybox/0003-gzip.patch

@@ -0,0 +1,18 @@
+From upstream: https://busybox.net/downloads/fixes-1.25.0/
+
+Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
+
+--- busybox-1.25.0/archival/gzip.c
++++ busybox-1.25.0-gzip/archival/gzip.c
+@@ -2220,10 +2220,7 @@ int gzip_main(int argc UNUSED_PARAM, cha
+ 	opt >>= ENABLE_GUNZIP ? 7 : 5; /* drop cfv[dt]qn bits */
+ 	if (opt == 0)
+ 		opt = 1 << 6; /* default: 6 */
+-	/* Map 1..3 to 4 */
+-	if (opt & 0x7)
+-		opt |= 1 << 4;
+-	opt = ffs(opt >> 3);
++	opt = ffs(opt >> 4); /* Maps -1..-4 to [0], -5 to [1] ... -9 to [5] */
+ 	max_chain_length = 1 << gzip_level_config[opt].chain_shift;
+ 	good_match	 = gzip_level_config[opt].good;
+ 	max_lazy_match	 = gzip_level_config[opt].lazy2 * 2;

package/busybox/0004-ip.patch

@@ -0,0 +1,18 @@
+From upstream: https://busybox.net/downloads/fixes-1.25.0/
+
+Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
+
+--- busybox-1.25.0/networking/libiproute/iproute.c
++++ busybox-1.25.0-ip/networking/libiproute/iproute.c
+@@ -362,10 +362,9 @@ IF_FEATURE_IP_RULE(ARG_table,)
+ 		req.r.rtm_scope = RT_SCOPE_NOWHERE;
+ 
+ 	if (cmd != RTM_DELROUTE) {
++		req.r.rtm_scope = RT_SCOPE_UNIVERSE;
+ 		if (RTPROT_BOOT != 0)
+ 			req.r.rtm_protocol = RTPROT_BOOT;
+-		if (RT_SCOPE_UNIVERSE != 0)
+-			req.r.rtm_scope = RT_SCOPE_UNIVERSE;
+ 		if (RTN_UNICAST != 0)
+ 			req.r.rtm_type = RTN_UNICAST;
+ 	}

package/busybox/0005-ntpd.patch

@@ -0,0 +1,20 @@
+From upstream: https://busybox.net/downloads/fixes-1.25.0/
+
+Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
+
+--- busybox-1.25.0/networking/ntpd.c
++++ busybox-1.25.0-ntpd/networking/ntpd.c
+@@ -2051,6 +2051,13 @@ recv_and_process_client_pkt(void /*int f
+ 		goto bail;
+ 	}
+ 
++	/* Respond only to client and symmetric active packets */
++	if ((msg.m_status & MODE_MASK) != MODE_CLIENT
++	 && (msg.m_status & MODE_MASK) != MODE_SYM_ACT
++	) {
++		goto bail;
++	}
++
+ 	query_status = msg.m_status;
+ 	query_xmttime = msg.m_xmttime;
+