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Ensure unprivileged users have unique tmp and home dirs #1278
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cbaenziger
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Oh, also to explain; we override |
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cbaenziger
commented
Nov 1, 2018
cbaenziger
commented
Nov 1, 2018
| # see if user still has any prescence on this machine | ||
| pgrep -u "$PAM_USER" && exit 0 | ||
| # if no prescense of user, remove all trace of their activity | ||
| rm -rf "<%= @polyinstantion_dir %>/home_$PAM_USER" \ |
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Chris asks please ensure that hardlink traversal isn't a risk here.
cbaenziger
commented
Nov 1, 2018
cookbooks/bcpc/recipes/pam.rb
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| source 'pam_namespace.conf.erb' | ||
| mode 500 | ||
| variables(lazy {{ real_home_dir_users: | ||
| node['bcpc']['pam_namespace']['real_home_dir_users'].join(','), |
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Ron asks, please .uniq on node['bcpc']['pam_namespace']['real_home_dir_users'].
cbaenziger
commented
Nov 1, 2018
cbaenziger
commented
Nov 1, 2018
vt0r
reviewed
Nov 1, 2018
vt0r
reviewed
Nov 1, 2018
vt0r
reviewed
Nov 1, 2018
cookbooks/bcpc/recipes/pam.rb
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| source 'pam_namespace.conf.erb' | ||
| mode 500 | ||
| variables(lazy {{ real_home_dir_users: | ||
| node['bcpc']['pam_namespace']['real_home_dir_users'].join(','), |
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Not sure if this would work, since I haven't tested it: Working. See below comment.
Suggested change
| node['bcpc']['pam_namespace']['real_home_dir_users'].join(','), | |
| node['bcpc']['pam_namespace']['real_home_dir_users'].uniq.sort.join(','), |
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Seems ok
[1] pry(main)> blah = %w(hdfs hdfs yarn hbase mapred hdfs hbase yarn mapred mapred hdfs hbase hadoop)
=> ["hdfs", "hdfs", "yarn", "hbase", "mapred", "hdfs", "hbase", "yarn", "mapred", "mapred", "hdfs", "hbase", "hadoop"]
[2] pry(main)> blah.uniq.sort.join(',')
=> "hadoop,hbase,hdfs,mapred,yarn"
macmaster
approved these changes
Nov 1, 2018
|
All requested changes made |
Also DRY-up sysctl/pam code repeated in Kafka and Hadoop; should be in BCPC
vt0r
reviewed
Nov 2, 2018
| directory '/inst-dirs' do | ||
| user 'root' | ||
| group 'root' | ||
| mode 0o000 |
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Suggested change
| mode 0o000 | |
| mode 0o0000 |
vt0r
reviewed
Nov 2, 2018
|
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| if [ -z "$PAM_TYPE" -o "$PAM_TYPE" == "open_session" ]; then | ||
| # need to setup the polyinstantation directory for login | ||
| mkdir -pm 000 "/dev/shm/<%= @shm_polyinstantion_dir %>" \ |
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Looks like this got merged out:
Suggested change
| mkdir -pm 000 "/dev/shm/<%= @shm_polyinstantion_dir %>" \ | |
| mkdir -pm 0000 "/dev/shm/<%= @shm_polyinstantion_dir %>" \ |
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This PR introduces pam_namespaces to ensure that each user gets its own kernel usernamespace for its potential state directories that are managed outside YARN. One further addition is automatic creation and clean-up of directories as needed using pam_exec.
Providing per-user namespaces means we can prevent accidental data sharing and we will prevent many imporoper uses of temporary directories by pro-actively cleaning them up. We have seen many users impact themselves with both anti-patterns and similarly when a user disconnects we will ensure they stop taking up space on our root partition for what should be their ephemeral home directory. We will need to notify users of this change!
The directories affected are listed in `/etc/secuirty/namespaces.conf. Users listed in that file are excluded from that line.
The directories created in
inst_dir.sh.erbare the necessary directories for pam_namespace to create directories and when the user is no longer running any processes and the user terminations its session the script is called to remove the directories. (If one usesnohupor such you can hold your directory around I think but I am not too concerned about that right now; we can write clean-up logic if need be later; similarly no quotas are introduced here but use of ZFS or possibly LVM could allow us to easily do that.)The structure under the polyinstantion directory looks like follows; and inside each directory is what the user see: