This bug is missing log files that will aid in diagnosing the problem.
While running an Ubuntu kernel (not a mainline or third-party kernel)
please enter the following command in a terminal window:
apport-collect 1824050
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable
to run this command, please add a comment stating that fact and change
the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the
Ubuntu Kernel Team.
** Changed in: linux (Ubuntu)
Status: New => Incomplete
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1824050
Title:
access.W_OK yields -1 EACCES (permission denied) on NFS mountpoints
Status in linux package in Ubuntu:
Incomplete
Bug description:
When upgrading from xenial kernel (4.4.0-145) to linux-image-generic-
hwe-16.04 (4.15.0-47) I am no longer able to run an application that
checks it's data directory for write access/path traversal when that
directory is an NFS share. This works on 4.4 and 3.13 kernels that I
tested with but fails on 4.15. I'm using NFSv3 and have seen the
behavior with both a synology NAS as the nfs-server as well as my
xenial desktop as the nfs-server.
To reproduce:
0.) Boot test machine with kernel 4.15.0-47
1.) set up a NFS export on another machine (nfs-server)
/etc/exports:
/srv/nfstest 192.168.100.100(rw,sync,no_subtree_check)
2.) mount the NFS share on the test machine and give a non-root user
ownership of the mount, in my case I have a user: aptly, with
home=/var/lib/aptly, and I mounted the NFS at /var/lib/aptly/test.
aptly:aptly owns /var/lib/aptly/test.
/etc/fstab:
192.168.100.101:/srv/nfstest /var/lib/aptly/test nfs rw,mountvers=3
3.) attempt to call access.W_OK on the mount as the non-root user `strace
./testaccess.py`
stderr:
...
access("/var/lib/aptly/test", W_OK) = -1 EACCES (Permission denied)
...
stdout:
('Writeable:', False)
('user r,e,s', (5062, 5062, 5062))
('group r,e,s', (5062, 5062, 5062))
posix.stat_result(st_mode=16895, st_ino=101188113, st_dev=48, st_nlink=3,
st_uid=5062, st_gid=5062, st_size=4096, st_atime=1554858490,
st_mtime=1554858633, st_ctime=1554858633)
testaccess.py:
#!/usr/bin/python
import os
import sys
from pprint import pprint
directory = '/var/lib/aptly/test'
if __name__ == "__main__":
writeable = os.access(directory, os.W_OK)
print("Writeable:", writeable)
print("user r,e,s", os.getresuid())
print("group r,e,s", os.getresgid())
pprint(os.stat(directory))
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1824050/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : [email protected]
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
