Ticket #45 (new defect)

Opened 15 months ago

a way to bypass file read permissions using fuse client:

Reported by: hubcap Owned by: parl
Priority: major Milestone:
Component: Kernel module Version: latest
Keywords: fuse kernel module permissions bypass Cc:

Description

This bug was reported by Andrew Savchenko, bircoph@…...

Hello,

On Mon, 12 Mar 2012 19:56:14 -0400 Kevin Stone wrote:

The invalid argument on chmod in fuse is fixed here:

 http://www.orangefs.org/trac/orangefs/changeset/9212

Thanks, it works. Though I found a way to bypass file read
permissions using fuse client:

1) Mount pvfs2 using pvfs2-client.
2) do as root:
# touch secret_file
# chmod 0600 secret_file
# echo secret_data > secret_file
3) do as user:
$ pvfs2fuse -o fs_spec=" tcp://host:3334/pvfs2-fs" mountpoint
$ ll secret_file
-rw------- 0 root root 12 Mar 13 19:58 secret_file
$ cat secret_file
secret_data

Parent directory is owned by root.
This works only for data read, you can't delete or modify file.
pvfs2-client works normally.
This doesn't work for directories, files only.
With default_permissions fuse option this also works as expected.

I know, security is not a primary goal for PFVS2 and most of
distributed file systems, but nevertheless it will be good to fix
this as well.

Best regards,
Andrew Savchenko

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