Mount points insecure #202

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1. fklemme commented on Apr 7, 2020

   

   fklemme

   on Apr 7, 2020

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   I'm not sure if this is a problem, as the user cannot specify docker arguments and thus not force to run the container as root user.

   So this is bad:

   docker run -v /root:/forbidden ubuntu bash -c "id; touch /forbidden/thing; ls /forbidden"
   uid=0(root) gid=0(root) groups=0(root)
   thing
   

   But this is fine:

   docker run --user "$(id -u):$(id -g)" -v /root:/forbidden ubuntu bash -c "id; touch /forbidden/thing; ls /forbidden"
   uid=1000 gid=1000 groups=1000
   touch: cannot touch '/forbidden/thing': Permission denied
   ls: cannot open directory '/forbidden': Permission denied
   

   And I believe the process is also running as that user from the hosts perspective. I'm not sure though what happens if the containers has sudo installed. So wether the process will become owned by root on the host if the user does sudo on the inside.