Hi, I have seen a regression, that I think is caused by:
commit dbe9a4173ea53b72b2c35d19f676a85b69f1c9fe Author: Eric W. Biederman <[email protected]> Date: Thu Sep 6 18:20:01 2012 +0000 scm: Don't use struct ucred in NETLINK_CB and struct scm_cookie. With this commit the value send as uid when credentials are missing changes from -1 to overflowuid (default -2, the 'nobody' user). I was using dbus-send to perform a method call on a gdbus server. And sometimes I fall victim to the race condition caused by: commit 16e5726 ("af_unix: dont send SCM_CREDENTIALS by default") And then there will be no credentials on the socket. The glib library checks the uid, and if it is -1, it will fall back to using SO_PEERCRED and things will work for me. But since the commit in $subject changes the uid I get failure with NoReply from dbus-send. It seems that before the commit in $subject that the function from_kuid_munged was only called if there were credentials present. Otherwise we would set uid to -1. Now uid gets set to -1 if there is no credentials but from_kuid_munged is always called. And from the documentation of from_kuid_munged it states that it 'never fails and always returns a valid uid'. And in the case of uid being -1, it returns overflowuid. So this seems like it broke glib. Caused by 1) the introduced race condition that makes it not totally safe to set SO_PEERCRED on the accepted socket and 2) that the value of uid when credentials are missing changed from -1 to overflowuid. Thanks for your time Jonas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
