Blame SOURCES/ntp-4.2.6p5-cve-2017-6464.patch

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2017-02-12 09:49:29+01:00, perlinger@ntp.org
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  [Sec 3389] NTP-01-016: Denial of Service via Malformed Config
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diff -up ntp-4.2.6p5/ntpd/ntp_config.c.cve-2017-6464 ntp-4.2.6p5/ntpd/ntp_config.c
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--- ntp-4.2.6p5/ntpd/ntp_config.c.cve-2017-6464	2017-03-22 12:54:11.257454635 +0100
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+++ ntp-4.2.6p5/ntpd/ntp_config.c	2017-03-22 12:57:06.919024166 +0100
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@@ -311,6 +311,9 @@ void ntpd_set_tod_using(const char *);
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 static u_int32 get_pfxmatch(const char **, struct masks *);
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 static u_int32 get_match(const char *, struct masks *);
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 static u_int32 get_logmask(const char *);
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+static int/*BOOL*/ is_refclk_addr(const struct address_node * addr);
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+
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+
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 static int getnetnum(const char *num,sockaddr_u *addr, int complain,
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 		     enum gnn_type a_type);
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 static int get_multiple_netnums(const char *num, sockaddr_u *addr,
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@@ -1342,7 +1344,10 @@ create_peer_node(
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 			break;
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 		case T_Ttl:
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-			if (my_node->ttl >= MAX_TTL) {
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+			if (is_refclk_addr(addr)) {
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+				msyslog(LOG_ERR, "'ttl' does not apply for refclocks");
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+				errflag = 1;
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+			} else if (option->value.i < 0 || option->value.i >= MAX_TTL) {
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 				msyslog(LOG_ERR, "ttl: invalid argument");
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 				errflag = 1;
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 			}
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@@ -1351,7 +1355,12 @@ create_peer_node(
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 			break;
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 		case T_Mode:
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-			my_node->ttl = option->value.i;
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+			if (is_refclk_addr(addr)) {
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+				my_node->ttl = option->value.i;
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+			} else {
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+				msyslog(LOG_ERR, "'mode' does not apply for network peers");
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+				errflag = 1;
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+			}
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 			break;
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		case T_Key:
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@@ -2674,6 +2685,16 @@ apply_enable_disable(
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 	}
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 }
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+/* Hack to disambiguate 'server' statements for refclocks and network peers.
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+ * Please note the qualification 'hack'. It's just that.
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+ */
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+static int/*BOOL*/
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+is_refclk_addr(
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+	const struct address_node * addr
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+	)
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+{
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+	return addr && addr->address && !strncmp(addr->address, "127.127.", 8);
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+}
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 static void
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 config_system_opts(
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@@ -2920,7 +2941,9 @@ config_ttl(
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 		curr_ttl = next_node(curr_ttl);
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 	}
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-	sys_ttlmax = i - 1;
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+
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+	if (i)
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+		sys_ttlmax = i - 1;
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 }
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diff -up ntp-4.2.6p5/ntpd/ntp_proto.c.cve-2017-6464 ntp-4.2.6p5/ntpd/ntp_proto.c
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--- ntp-4.2.6p5/ntpd/ntp_proto.c.cve-2017-6464	2017-03-22 12:54:11.270454677 +0100
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+++ ntp-4.2.6p5/ntpd/ntp_proto.c	2017-03-22 12:54:11.279454706 +0100
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@@ -3017,8 +3017,9 @@ peer_xmit(
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 			}
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 		}
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 		peer->t21_bytes = sendlen;
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-		sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl],
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-		    &xpkt, sendlen);
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+		sendpkt(&peer->srcadr, peer->dstadr,
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+			sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
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+			&xpkt, sendlen);
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 		peer->sent++;
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 		peer->throttle += (1 << peer->minpoll) - 2;
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@@ -3330,8 +3331,9 @@ peer_xmit(
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 		exit (-1);
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 	}
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 	peer->t21_bytes = sendlen;
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-	sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], &xpkt,
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-	    sendlen);
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+	sendpkt(&peer->srcadr, peer->dstadr,
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+		sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
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+		&xpkt, sendlen);
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 	peer->sent++;
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 	peer->throttle += (1 << peer->minpoll) - 2;
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