From 7864c7a70ce00369194e734eb2842ecc5f8db531 Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Wed, 13 Jan 2010 17:40:20 +0100
Subject: [PATCH] Don't reply to invalid chronyc packets

---
 cmdmon.c | 49 +++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/cmdmon.c b/cmdmon.c
index e88d7c3..c9ce0e9 100644
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -1593,6 +1593,7 @@ read_from_cmd_socket(void *anything)
   int valid_ts;
   int authenticated;
   int localhost;
+  int allowed;
   unsigned short rx_command;
   unsigned long rx_message_token;
   unsigned long tx_message_token;
@@ -1642,8 +1643,31 @@ read_from_cmd_socket(void *anything)
 
   localhost = (remote_ip == 0x7f000001UL);
 
-  if ((!ADF_IsAllowed(access_auth_table, remote_ip)) &&
-      (!localhost)) {
+  allowed = ADF_IsAllowed(access_auth_table, remote_ip) || localhost;
+
+  if ((read_length < offsetof(CMD_Request, data)) ||
+      (rx_message.version != PROTO_VERSION_NUMBER) ||
+      (rx_message.pkt_type != PKT_TYPE_CMD_REQUEST) ||
+      (rx_message.res1 != 0) ||
+      (rx_message.res2 != 0)) {
+
+    /* We don't know how to process anything like this */
+    if (allowed)
+      CLG_LogCommandAccess(remote_ip, CLG_CMD_BAD_PKT, cooked_now.tv_sec);
+    
+    return;
+  }
+
+  if (read_length != expected_length) {
+    LOG(LOGS_WARN, LOGF_CmdMon, "Read incorrectly sized packet from %s:%hu", UTI_IPToDottedQuad(remote_ip), remote_port);
+    if (allowed)
+      CLG_LogCommandAccess(remote_ip, CLG_CMD_BAD_PKT, cooked_now.tv_sec);
+    /* For now, just ignore the packet.  We may want to send a reply
+       back eventually */
+    return;
+  }
+
+  if (!allowed) {
     /* The client is not allowed access, so don't waste any more time
        on him.  Note that localhost is always allowed access
        regardless of the defined access rules - otherwise, we could
@@ -1664,25 +1688,6 @@ read_from_cmd_socket(void *anything)
   }
 
 
-  if (read_length != expected_length) {
-    LOG(LOGS_WARN, LOGF_CmdMon, "Read incorrectly sized packet from %s:%hu", UTI_IPToDottedQuad(remote_ip), remote_port);
-    CLG_LogCommandAccess(remote_ip, CLG_CMD_BAD_PKT, cooked_now.tv_sec);
-    /* For now, just ignore the packet.  We may want to send a reply
-       back eventually */
-    return;
-  }
-
-  if ((rx_message.version != PROTO_VERSION_NUMBER) ||
-      (rx_message.pkt_type != PKT_TYPE_CMD_REQUEST) ||
-      (rx_message.res1 != 0) ||
-      (rx_message.res2 != 0)) {
-
-    /* We don't know how to process anything like this */
-    CLG_LogCommandAccess(remote_ip, CLG_CMD_BAD_PKT, cooked_now.tv_sec);
-    
-    return;
-  }
-
   rx_command = ntohs(rx_message.command);
 
   /* OK, we have a valid message.  Now dispatch on message type and process it. */
@@ -1809,7 +1814,7 @@ read_from_cmd_socket(void *anything)
     tx_message.status = htons(STT_INVALID);
     tx_message.reply = htons(RPY_NULL);
   } else {
-    int allowed = 0;
+    allowed = 0;
 
     /* Check level of authority required to issue the command */
     switch(permissions[rx_command]) {