** Description changed: [impact] rpcbind binds to a 'random' reserved port at startup, which can conflict with the reserved port number for other applications that actually 'own' the reserved port number. One example is cups, which uses the reserved port 631. This prevents the actual 'owner' of the reserved port from starting, since it can't bind to its reserved port. Additionally, this can raise alarms from security monitoring software that does not expect programs to be listening on random reserved ports. [test case] start rpcbind and check which ports it is listening on, e.g.: $ sudo netstat --inet -p -l | grep rpcbind | grep -v sunrpc - udp 0 0 0.0.0.0:614 0.0.0.0:* 4678/rpcbind + udp 0 0 0.0.0.0:614 0.0.0.0:* 4678/rpcbind each time rpcbind is restarted, it will be listening to a different 'random' port. [regression potential] - this adds a method to disable rpcbind from listening to the 'random' - port. any regression would likely prevent rpcbind from starting, or may - cause problems with the interaction between rpcinfo and rpcbind, as - rpcinfo may use the random reserved port in some cases, as detailed in - the Debian bug. + this adds a way to disable rpcbind from listening to the 'random' port. + any regression would likely prevent rpcbind from starting, or may cause + problems with the interaction between rpcinfo and rpcbind, as rpcinfo + may use the random reserved port in some cases, as detailed in the + Debian bug. [scope] This is needed only for Bionic and earlier. In Focal and later, and in Debian, rpcbind defaults to not opening the random reserved port. The admin can use the -r parameter to cause rpcbind to restore the old behavior of opening the random reserved port. [other info] Note that the -r parameter is a Debian addition, and the upstream rpcbind has disabled the random port functionality at build time; there is no runtime parameter to allow the admin to choose the behavior. Also, as discussed in the Debian bug, disabling this rpcbind 'feature' is known to cause problems for the rpcinfo program, which is why Debian introduced the -r parameter. So, when this -r parameter is backported to Bionic and earlier, we must retain the default behavior for those releases, which is for rpcbind to open the random reserved port. - TBD: specific method to disable rmtcalls in backport + Thus, the patch for this will first backport the upstream patch that adds functionality to be able to disable the 'remote calls' function, and also backports the debian patch to change that from a compile-time to run-time option. Then, another patch is added, which changes the default back to the behavior of x/b, which is for remote calls to be enabled by default, + and also adds a check for the existence of an environment variable "RPCBIND_RMTCALLS_DEFAULT_DISABLED" which, if defined (to anything), will change the default to disabled. + This allows 1) retaining the existing default behavior of rpcbind in x + and b, while also 2) providing a mechanism to change that default for + anyone who does *not* want remote calls to be enabled, and 3) allowing + the mechanism to change the default to remain in place after an upgrade + to Focal. Using the environment variable, instead of changing or adding + the cmdline parameter, allows anyone using the variable to disable the + remote calls default to upgrade to Focal without breaking rpcbind. After + the upgrade to Focal, the environment variable (defined in + /etc/default/rpcbind and/or /etc/rpcbind.conf) will simply be ignored + without any change needed to the rpcbind package in Focal or later. [original description] As this backports that functionality, it Binary package hint: cups cups 1.3.9-2ubuntu4 From /var/log/cups/error_log: cups: unable to bind socket for address 127.0.0.1:631 - Address already in use. Nothing actually looks wrong. 127.0.0.1:631 is only in use by cupsd when started.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to cups in Ubuntu. https://bugs.launchpad.net/bugs/304393 Title: rpcbind grabs ports used by other daemons such as cupsd Status in cups package in Ubuntu: Invalid Status in rpcbind package in Ubuntu: Fix Released Status in rpcbind source package in Xenial: In Progress Status in rpcbind source package in Bionic: In Progress Status in rpcbind package in Debian: Fix Released Status in Fedora: Confirmed Bug description: [impact] rpcbind binds to a 'random' reserved port at startup, which can conflict with the reserved port number for other applications that actually 'own' the reserved port number. One example is cups, which uses the reserved port 631. This prevents the actual 'owner' of the reserved port from starting, since it can't bind to its reserved port. Additionally, this can raise alarms from security monitoring software that does not expect programs to be listening on random reserved ports. [test case] start rpcbind and check which ports it is listening on, e.g.: $ sudo netstat --inet -p -l | grep rpcbind | grep -v sunrpc udp 0 0 0.0.0.0:614 0.0.0.0:* 4678/rpcbind each time rpcbind is restarted, it will be listening to a different 'random' port. [regression potential] this adds a way to disable rpcbind from listening to the 'random' port. any regression would likely prevent rpcbind from starting, or may cause problems with the interaction between rpcinfo and rpcbind, as rpcinfo may use the random reserved port in some cases, as detailed in the Debian bug. [scope] This is needed only for Bionic and earlier. In Focal and later, and in Debian, rpcbind defaults to not opening the random reserved port. The admin can use the -r parameter to cause rpcbind to restore the old behavior of opening the random reserved port. [other info] Note that the -r parameter is a Debian addition, and the upstream rpcbind has disabled the random port functionality at build time; there is no runtime parameter to allow the admin to choose the behavior. Also, as discussed in the Debian bug, disabling this rpcbind 'feature' is known to cause problems for the rpcinfo program, which is why Debian introduced the -r parameter. So, when this -r parameter is backported to Bionic and earlier, we must retain the default behavior for those releases, which is for rpcbind to open the random reserved port. Thus, the patch for this will first backport the upstream patch that adds functionality to be able to disable the 'remote calls' function, and also backports the debian patch to change that from a compile-time to run-time option. Then, another patch is added, which changes the default back to the behavior of x/b, which is for remote calls to be enabled by default, and also adds a check for the existence of an environment variable "RPCBIND_RMTCALLS_DEFAULT_DISABLED" which, if defined (to anything), will change the default to disabled. This allows 1) retaining the existing default behavior of rpcbind in x and b, while also 2) providing a mechanism to change that default for anyone who does *not* want remote calls to be enabled, and 3) allowing the mechanism to change the default to remain in place after an upgrade to Focal. Using the environment variable, instead of changing or adding the cmdline parameter, allows anyone using the variable to disable the remote calls default to upgrade to Focal without breaking rpcbind. After the upgrade to Focal, the environment variable (defined in /etc/default/rpcbind and/or /etc/rpcbind.conf) will simply be ignored without any change needed to the rpcbind package in Focal or later. [original description] As this backports that functionality, it Binary package hint: cups cups 1.3.9-2ubuntu4 From /var/log/cups/error_log: cups: unable to bind socket for address 127.0.0.1:631 - Address already in use. Nothing actually looks wrong. 127.0.0.1:631 is only in use by cupsd when started. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cups/+bug/304393/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
