** Description changed: [ Impact ] On Ubuntu Core 24 calling the command line useradd --extrausers --groups somegroup somenewuser ... fails with: useradd: cannot lock /etc/group; try again later. It worked on 22.04. /etc is not writable. It also fails if somegroup is a group in extrausers. [ Test Plan ] Part of the upload is adding an autopkgtest script testing useradd and usermod in the extrausers+readonly-etc case. In addition, the following commands should be run as root in a fresh container: ``` # Install prerequisites apt install libnss-extrausers sed -i -r -e'/^(passwd|group|shadow|gshadow)/ s/$/ extrausers/' /etc/nsswitch.conf # enable extrausers in group, passwd, shadow and gshadow # Sanity checks of "normal" path groupadd etcgroup useradd --groups etcgroup etcuser id etcuser | grep etcgroup groupadd etcgroup2 usermod --groups etcgroup2 etcuser id etcuser | grep etcgroup2 useradd --groups nullgroup etcuser || echo Successfully rejected invalid group ls /var/lib/extrausers/ # should be empty # Sanity checks of "extrausers" path in rw context groupadd --extrausers extragroup useradd --extrausers --groups extragroup extrauser # currently fails id extrauser | grep extragroup useradd --extrausers extrauser2 id extrauser2 - usermod --extrausers --groups extragroup extrauser2 + usermod --groups extragroup extrauser2 id extrauser2 | grep extragroup # Sanity checks of "extrausers" path in ro context mv /etc /etc-rw mkdir /etc mount -o bind,ro /etc-rw /etc groupadd --extrausers extragroup2 useradd --extrausers --groups etcgroup extrauser3 id extrauser4 | grep etcgroup - usermod --extrausers --groups extragroup2 extrauser3 + usermod --groups extragroup2 extrauser3 id extrauser4 | grep extragroup2 ``` Furthermore, validation from the Ubuntu Core team that this actually fixes their use case is required. [ Where problems could occur ] Regression potential is in the group validation stage of the `usermod` and `useradd` tools. Besides the usual risks related to C code, the various failure scenarios that come to mind are: * try to add the user to an non-existing local group, which would fail further down with a different error message * actually fail to identify a valid local group * Fail to either add the user to the system, or the user to the group * Update the wrong file (/var/lib/extrausers/* vs /etc/*)
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2063200 Title: useradd --extrausers --groups tries to lock /etc/group To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/2063200/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
