Am Montag, 30. August 2021, 21:58:47 CEST schrieb Greg Wooledge: > On Mon, Aug 30, 2021 at 09:01:33PM +0200, Rainer Dorsch wrote: > > rd@h370:~/tmp.nobackup$ ls -l /tmp/123 > > -rw-rw-r-- 1 rd users 0 30. Aug 20:42 /tmp/123 > > > > User ka overwrites it with the content of another file (atomically): > > > > ka@h370:~$ echo test > 123 > > ka@h370:~$ mv 123 /tmp/123 > > mv: cannot move '123' to '/tmp/123': Operation not permitted > > In order to perform this move, ka would first need to unlink the > existing /tmp/123 file. ka cannot do that, because the /tmp directory > is "sticky". Only "rd" (or root) can do it. > > > Maybe moving removes a node in /tmp, > > Yes. You can verify with strace if you're curious enough. > > > so I am trying to append to the file as a > > test: > > > > -rw-rw-r-- 1 rd users 0 30. Aug 20:35 /tmp/123 > > > > ka@h370:~$ id > > uid=1401(ka) gid=1401(ka) Gruppen=1401(ka),20(dialout),21(fax),24(cdrom), > > 30(dip),44(video),46(plugdev),100(users),1000(sispmctl) > > ka@h370:~$ ls -l /tmp/123 > > -rw-rw-r-- 1 rd users 0 30. Aug 20:35 /tmp/123 > > ka@h370:~$ echo test >> /tmp/123 > > -bash: /tmp/123: Permission denied > > That one should have worked, due to the secondary group membership. > > unicorn:~$ sudo touch /tmp/123; sudo chgrp video /tmp/123; sudo chmod 664 > /tmp/123 [sudo] password for greg: > unicorn:~$ ls -l /tmp/123 > -rw-rw-r-- 1 root video 0 Aug 30 15:56 /tmp/123 > unicorn:~$ id > uid=1000(greg) gid=1000(greg) > groups=1000(greg),24(cdrom),25(floppy),27(sudo),29(audio),30(dip),44(video) > ,46(plugdev),108(netdev) unicorn:~$ echo stuff >> /tmp/123 > unicorn:~$ > > It works for me. Is your /tmp a non-Unix file system, or is it mounted > with any unusual options?
Thanks for testing and your quick response. Hmm...your example works for me as well rd@h370:~/tmp.nobackup$ sudo touch /tmp/123; sudo chgrp video /tmp/123; sudo chmod 664 /tmp/123 [sudo] Passwort für rd: rd@h370:~/tmp.nobackup$ ls -l /tmp/123 -rw-rw-r-- 1 root video 0 30. Aug 22:52 /tmp/123 rd@h370:~/tmp.nobackup$ id uid=2809(rd) gid=2809(rd) Gruppen=2809(rd),4(adm),20(dialout),21(fax), 24(cdrom),25(floppy),27(sudo),30(dip),44(video),46(plugdev),100(users), 114(lpadmin),118(scanner),126(docker),127(vboxusers),130(i2psvc), 131(wireshark),141(libvirt),1000(sispmctl) rd@h370:~/tmp.nobackup$ echo stuff >> /tmp/123 rd@h370:~/tmp.nobackup$ As soon as I do a chown to a non-root user on /tmp/123 it does not work for me anymore. Is root somehow treated differently as other users? I am not aware of special mount options for /tmp, it should be a standard installation: rd@h370:~/tmp.nobackup$ mount sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime) proc on /proc type proc (rw,nosuid,nodev,noexec,relatime) udev on /dev type devtmpfs (rw,nosuid,relatime,size=16342996k,nr_inodes=4085749,mode=755) devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000) tmpfs on /run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=3273064k,mode=755) /dev/mapper/b370--vg-root on / type ext4 (rw,relatime,errors=remount-ro) securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev) tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k) cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot) pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime) efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime) none on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700) systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=30,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=13462) hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=2M) mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime) debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime) tracefs on /sys/kernel/tracing type tracefs (rw,nosuid,nodev,noexec,relatime) fusectl on /sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime) configfs on /sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime) sunrpc on /run/rpc_pipefs type rpc_pipefs (rw,relatime) /dev/sda2 on /boot type ext2 (rw,relatime) /dev/sda1 on /boot/efi type vfat (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount- ro) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime) -hosts on /mnt/net type autofs (rw,relatime,fd=6,pgrp=1674,timeout=60,minproto=5,maxproto=5,indirect,pipe_ino=19859) tmpfs on /run/user/113 type tmpfs (rw,nosuid,nodev,relatime,size=3273064k,nr_inodes=818266,mode=700,uid=113,gid=117) tmpfs on /run/user/2809 type tmpfs (rw,nosuid,nodev,relatime,size=3273064k,nr_inodes=818266,mode=700,uid=2809,gid=2809) -hosts on /mnt/net/fs/mnt/disk/data type autofs (rw,relatime,fd=6,pgrp=1674,timeout=60,minproto=5,maxproto=5,offset,pipe_ino=19859) -hosts on /mnt/net/fs/mnt/disk/scratch type autofs (rw,relatime,fd=6,pgrp=1674,timeout=60,minproto=5,maxproto=5,offset,pipe_ino=19859) -hosts on /mnt/net/fs/mnt/disk/scratch2 type autofs (rw,relatime,fd=6,pgrp=1674,timeout=60,minproto=5,maxproto=5,offset,pipe_ino=19859) -hosts on /mnt/net/fs/mnt/disk/smarthome type autofs (rw,relatime,fd=6,pgrp=1674,timeout=60,minproto=5,maxproto=5,offset,pipe_ino=19859) fs:/mnt/disk/data on /mnt/net/fs/mnt/disk/data type nfs4 (rw,nosuid,nodev,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.7.203,local_lock=none,addr=192.168.7.2) portal on /run/user/2809/doc type fuse.portal (rw,nosuid,nodev,relatime,user_id=2809,group_id=2809) fs:/mnt/disk/scratch on /mnt/net/fs/mnt/disk/scratch type nfs4 (rw,nosuid,nodev,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.7.203,local_lock=none,addr=192.168.7.2) rd@h370:~/tmp.nobackup$ Thanks Rainer -- Rainer Dorsch http://bokomoko.de/
