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The setuid, setgid, and sticky bits are not copied during copy_tree. Also start with very restrictive permissions before setting ownerships. This prevents situations in which users in a group with less permissions than others could win a race in opening the file before permissions are removed again. Proof of concept: $ echo $HOME /home/uwu $ install -o uwu -g fandom -m 604 /dev/null /home/uwu/owo $ ls -l /home/uwu/owo -rw----r-- 1 uwu fandom 0 Sep 4 00:00 /home/uwu/owo If /tmp is on another filesystem, then "usermod -md /tmp/uwu uwu" leads to this temporary situation: $ ls -l /tmp/uwu/owo -rw----r-- 1 root root 0 Sep 4 00:00 /tmp/uwu/owo This means that between openat and chownat_if_needed a user of group fandom could open /tmp/uwu/owo and read the content when it is finally written into the file.
shadow-utils
Introduction
The shadow-utils package includes the necessary programs for converting UNIX password files to the shadow password format, plus programs for managing user and group accounts. The pwconv command converts passwords to the shadow password format. The pwunconv command unconverts shadow passwords and generates a passwd file (a standard UNIX password file). The pwck command checks the integrity of password and shadow files. The lastlog command prints out the last login times for all users. The useradd, userdel, and usermod commands are used for managing user accounts. The groupadd, groupdel, and groupmod commands are used for managing group accounts.
Sites
Contacts
There are several ways to contact us:
- the general discussion mailing list
- the #shadow IRC channel on libera.chat:
- irc://irc.libera.chat/shadow
Mailing archives
- the general discussion mailing list archive
- the commit mailing list archive, only used for historical purposes
Authors and maintainers
Authors and maintainers are listed in AUTHORS.md.