Messages in this thread | | | Subject | Re: overlayfs: caller_credentials option bypass creator_cred | From | Mark Salyzyn <> | Date | Mon, 18 Jun 2018 14:59:50 -0700 |
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On 06/18/2018 12:43 PM, Vivek Goyal wrote: > Will it be acceptable to write security policies in such a way so that > mounter has access as well. Unfortunately No. Policy of minimizing attack surface for a contained root service (init in this case). Just because it can mount, does not mean it can modify critical content; an attacker could use this to open a hole.
> Current model does assume that mounter has privileges on underlying files.
Only ones it appears to need is the workdir AFAIK, had to add ability to create in the <wordir> xattr in order to enable r/w mounts later. Although not all corners were tested, I did not see any copy_up issues b/c the caller had the privs in the Android security model when mounted with this new flag.
-- Mark
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