MFC r303374:

  Due to dropped mbuf in netisr queue route(8) can fall into infinity
  loop of reading the rtsock's feed. When it used by some scripts,
  this leads to growing number of not finished route(8) instances and
  thus growing number of rtsock consumers. Add SIGALRM handler to prevent this.

1 files changed, 27 insertions, 1 deletions

diff --git a/sbin/route/route.c b/sbin/route/route.c
index a357a4d..ee312a4 100644
--- a/sbin/route/route.c
+++ b/sbin/route/route.c
@@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <paths.h>
+#include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -144,6 +145,16 @@ static int	fiboptlist_range(const char *, struct fibl_head_t *);
 
 static void usage(const char *) __dead2;
 
+#define	READ_TIMEOUT	10
+static volatile sig_atomic_t stop_read;
+
+static void
+stopit(int sig __unused)
+{
+
+	stop_read = 1;
+}
+
 static void
 usage(const char *cp)
 {
@@ -776,6 +787,7 @@ set_metric(char *value, int key)
 static void
 newroute(int argc, char **argv)
 {
+	struct sigaction sa;
 	struct hostent *hp;
 	struct fibl *fl;
 	char *cmd;
@@ -791,6 +803,12 @@ newroute(int argc, char **argv)
 	hp = NULL;
 	TAILQ_INIT(&fibl_head);
 
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = 0;
+	sa.sa_handler = stopit;
+	if (sigaction(SIGALRM, &sa, 0) == -1)
+		warn("sigaction SIGALRM");
+
 	cmd = argv[0];
 	if (*cmd != 'g' && *cmd != 's')
 		shutdown(s, SHUT_RD); /* Don't want to read back our messages */
@@ -1541,9 +1559,17 @@ rtmsg(int cmd, int flags, int fib)
 		return (-1);
 	}
 	if (cmd == RTM_GET) {
+		stop_read = 0;
+		alarm(READ_TIMEOUT);
 		do {
 			l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
-		} while (l > 0 && (rtm.rtm_seq != rtm_seq || rtm.rtm_pid != pid));
+		} while (l > 0 && stop_read == 0 &&
+		    (rtm.rtm_seq != rtm_seq || rtm.rtm_pid != pid));
+		if (stop_read != 0) {
+			warnx("read from routing socket timed out");
+			return (-1);
+		} else
+			alarm(0);
 		if (l < 0)
 			warn("read from routing socket");
 		else