[KARAF-7096] When rmiServerHost is 127.0.0.1, RMIServerImpl_Stub still uses hostname's IP

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.2.11, 4.3.1
• Fix Version/s: 4.2.12, 4.3.2
• Target Version/s: 4.2.12, 4.3.2
• Assignee: Grzegorz Grzybek
• Reporter: Grzegorz Grzybek
• Created: 08/Apr/21 12:49
• Updated: 09/Apr/21 05:38
• Resolved: 09/Apr/21 05:24

Description

It's a follow-up of the investigation from KARAF-6955. Copying the description:

I had problem after this change - jconsole stopped working and sample Java application ended with Connection refused exception.

I did enjoyable analysis and I found that:

• ports are opened on proper interfaces (::ffff:127.0.0.1 in my case, which is an IPv6 address from ::ffff:0:0/96 CIDR that represents Transition from IPv4 address block)
• I could connect to RMI Registry at port 1099 and even obtain karaf-root object from there, which:
  • is of javax.management.remote.rmi.RMIServer interface
  • is of javax.management.remote.rmi.RMIServerImpl_Stub implementation

The problem is that this stub contains:

ref: java.rmi.server.RemoteRef  = {sun.rmi.server.UnicastRef2@1918} 
...
 ref: sun.rmi.transport.LiveRef  = {sun.rmi.transport.LiveRef@1925} "[endpoint:[192.168.0.38:44444](remote),objID:[2f23195f:178a6a29327:-7ffa, 4962682433218761153]]"
  ep: sun.rmi.transport.Endpoint  = {sun.rmi.transport.tcp.TCPEndpoint@1927} "[192.168.0.38:44444]"
   host: java.lang.String  = "192.168.0.38"
   port: int  = 44444 (0xAD9C)

The problem is that when RMIServerImpl_Stub is created at server side by karaf.management.server bundle, the bind address of this remote object is NOT taken from rmiServerHost property of org.apache.karaf.management PID. It's taken from (top to bottom):

• sun.rmi.transport.tcp.TCPEndpoint#getLocalEndpoint()
• java.net.InetAddress#getLocalHost()
• java.net.InetAddressImpl#getLocalHostName()
• java.net.InetAddress#getAddressesFromNameService()
• java.net.Inet6AddressImpl#lookupAllHostAddr()
• getaddress() libc method
• /etc/hosts

The way to solve this is to set java.rmi.server.hostname system property to 127.0.0.1, so the Stub contains proper address.

Issue Links

• is caused by: KARAF-6955 JMX: With rmiRegistryHost = 127.0.0.1, Karaf should listen only on 127.0.0.1