Messages in this thread | | | Subject | procfs doesnt honor cap_dac_override | Date | Fri, 05 Nov 2010 18:33:45 -0400 | From | abirvalg@lavabit ... |
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We have a folder /proc/1/fd which contains symlinks. A superuser can do readlink() on those symlinks. I expected that a non-root process with cap_dac_override capability set to EP could also readlink() those symlinks in /proc/1/fd, but alas "Permission denied". Just to make sure that my process isn't the culprit, I ran it as a regular user with UID=1000, I set cap_dac_override=ep and navigated to /root folder (which is readable only by root) and did readlink() there. It worked. (/root folder is on ext4.) Bottom line: procfs doesnt allow readlink() on certain symlinks owned by root even with cap_dac_override set.
Is this an expected behaviour or is this a bug? Cheers.
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