From 7d2ec4fe85b4bc88a3be5cefd386c28fd2c709ad Mon Sep 17 00:00:00 2001
From: Ken Raeburn <raeburn@mit.edu>
Date: Mon, 21 Jul 2008 18:39:34 +0000
Subject: [PATCH] When reading from the routing socket, only provide enough
 space for the header and ignore the rest of the message.  Don't complain
 about message size as long as we got the bits of the header we care about.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@20552 dc483132-0cff-0310-8789-dd5450dbe970
---
 src/kdc/network.c | 52 ++++++++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 30 deletions(-)

diff --git a/src/kdc/network.c b/src/kdc/network.c
index f3b87a176..0cc673722 100644
--- a/src/kdc/network.c
+++ b/src/kdc/network.c
@@ -808,49 +808,41 @@ static char *rtm_type_name(int type)
 static void process_routing_update(struct connection *conn, const char *prog,
 				   int selflags)
 {
-    static struct {
-	struct rt_msghdr rtm;
-	char scratchbuf[1024];
-    } s;
     int n_read;
+    struct rt_msghdr rtm;
 
     krb5_klog_syslog(LOG_INFO, "routing socket readable");
-    while ((n_read = read(conn->fd, &s, sizeof(s))) > 0) {
-	if (n_read < sizeof(s.rtm)) {
-	    krb5_klog_syslog(LOG_ERR, "short read (%d/%d) from routing socket",
-			     n_read, (int) sizeof(s.rtm));
+    while ((n_read = read(conn->fd, &rtm, sizeof(rtm))) > 0) {
+	if (n_read < sizeof(rtm)) {
 	    /* Quick hack to figure out if the interesting
-	       fields are present in a short read.  */
-#define RS(FIELD) (offsetof(struct rt_msghdr, FIELD) + sizeof(s.rtm.FIELD))
+	       fields are present in a short read.
+
+	       A short read seems to be normal for some message types.
+	       Only complain if we don't have the critical initial
+	       header fields.  */
+#define RS(FIELD) (offsetof(struct rt_msghdr, FIELD) + sizeof(rtm.FIELD))
 	    if (n_read < RS(rtm_type) ||
 		n_read < RS(rtm_version) ||
-		n_read < RS(rtm_msglen))
+		n_read < RS(rtm_msglen)) {
+		krb5_klog_syslog(LOG_ERR,
+				 "short read (%d/%d) from routing socket",
+				 n_read, (int) sizeof(rtm));
 		return;
+	    }
 	}
 	krb5_klog_syslog(LOG_INFO,
 			 "got routing msg type %d(%s) v%d",
-			 s.rtm.rtm_type, rtm_type_name(s.rtm.rtm_type),
-			 s.rtm.rtm_version);
-	if (s.rtm.rtm_msglen > sizeof(s)) {
-	    krb5_klog_syslog(LOG_ERR,
-			     "routing message bigger than buffer (%d/%d)",
-			     s.rtm.rtm_msglen, (int) sizeof(s));
-	    /* This will probably start spewing messages.  Slow it
-	       down.  */
-	    sleep(1);
-	    return;
-	}
-	if (s.rtm.rtm_msglen != n_read) {
+			 rtm.rtm_type, rtm_type_name(rtm.rtm_type),
+			 rtm.rtm_version);
+	if (rtm.rtm_msglen > sizeof(rtm)) {
+	    /* It appears we get a partial message and the rest is
+	       thrown away?  */
+	} else if (rtm.rtm_msglen != n_read) {
 	    krb5_klog_syslog(LOG_ERR,
 			     "read %d from routing socket but msglen is %d",
-			     n_read, s.rtm.rtm_msglen);
-	    if (s.rtm.rtm_msglen < sizeof(s.rtm)) {
-		krb5_klog_syslog(LOG_ERR,
-				 "routing msglen shorter than header??");
-		return;
-	}
+			     n_read, rtm.rtm_msglen);
 	}
-	switch (s.rtm.rtm_type) {
+	switch (rtm.rtm_type) {
 	case RTM_ADD:
 	case RTM_DELETE:
 	case RTM_NEWADDR:
-- 
2.26.2