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Accepted
Nik
Asked: 2010-06-07 16:20:26 +0800 CST

Accidential CHMOD 755

  • 772

Alright, I accidentially chomdded everything to 755, which isn't as terrible as chowning everything to the local user. How insecure is this and how would I restore it easily, without reinstalling?

ubuntu chmod

2 Answers

  1. Best Answer

    Reinstall is the best option. I personally would always have the nagging feeling of something not done right even if the following work.

    1. Use another Ubuntu system to reference your permissions. Same Ubuntu version and architecture. 
      reference$ find / ! -type l \
         -path "^/tmp" -prune \
         -o -path "^/dev" -prune \
         -o -path "^/sys" -prune \
         -o -printf "%m %p\n" > /root/perms.txt
    2. copy /root/perms.txt to your main system

    3. Use /root/perms.txt to reference and modify permissions 

      main$ cat /root/perms.txt | while read LINE; do
perm=echo -E "$LINE" | awk '{print $1}'
filename=echo -E "$LINE" | sed 's/^$perm //'
      


      if [ -a $filename ]; then
    echo -E "$filename" >> /root/chmod-success.log
    chmod $perm $filename
else
    echo -E "$filename" >> /root/chmod-failure.log
fi
done

    4. check the errors in /root/chmod-success.log and /root/chmod-failure.log

    Anyway, there are just too many edge cases here that I cannot even imagine if this would work perfectly. Test on another non-production system first. And test on the main production system without the chmod $perm $filename line first

    • 9

  2. If you have an RPM based distro like Fedora/Redhat or CentOS you could run

    rpm -qa | xargs rpm --setperms

    That will fix all files that were installed via rpm.. the rest will have to be fixed by hand

    • 2