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Pierre Warnier
f3a20b2043
The reason gpasswd is setuid is that someone who is not root, but is named an administrator of one group, manages that group's membership. Nothing in the suite exercised a non-root caller of it, and that is the only place the omission shows: the multicall binary drops privilege for every applet not on its setuid list, so leaving gpasswd off that list produces a permission error there and nowhere else. It was off the list when the tool arrived. Twelve assertions: an administrator adds a member without being root and the change lands in both group and gshadow; a plain member may not change the membership, may not appoint administrators and may not use --root; and the administrator list is unchanged after all three refusals. Checked that the test bites by taking gpasswd back off the setuid list and rebuilding -- the administrator is then refused and the group file is untouched. Worth saying that the first attempt at that check appeared to show the fix was unnecessary; the build output had been suppressed and a stale binary was installed.