** Description changed:
[ Impact ]
sshfs mounts specified in /etc/fstab would fail to mount when a mount of
all filesystems specified in the fstab was attempted with mount -a. This
- was due to a missing noexec mount flag specification in the mount rules.
+ was due to a missing noexec mount flag specification in the mount rules
+ of fusermount3's profile.
[ Test Plan ]
- * The setup instructions assume no access to an existing SSH client-server
pair.
- - Spin up two Ubuntu Plucky VMs, one of which will be referred to as
sshfs-client and the other of which will be referred to as sshfs-server
- - Install openssh-server on the server and sshfs on the client
- - Ensure that the two machines are able to ping each other using a
[machine hostname].local address
- - Generate an SSH key on the client and copy it into the
~/.ssh/authorized_keys directory on the server
- - Ensure that the client can SSH into the server without a password prompt
(using the key)
- - Uncomment the "user_allow_other" line in sshfs-client's /etc/fuse.conf
- - Create a mountpoint directory somewhere inside sshfs-client's home
directory
- - Verify that a manual sshfs mount using `sshfs -o
_netdev,user,idmap=user,transform_symlinks,allow_other,default_permissions,uid=1000,gid=1000
username@sshfs-server:/path/to/directory /home/username/mountpoint` works, and
then unmount the newly created mount
- - Add the entry `username@sshfs-server:/path/to/directory
/home/username/mountpoint fuse.sshfs
_netdev,user,idmap=user,transform_symlinks,allow_other,default_permissions,uid=1000,gid=1000
0 0` to sshfs-client's /etc/fstab
- - Attempt to mount the new fstab mount entry with `mount -a`
- - Without the fix: the mount will fail with a permission denied error and
generate an AppArmor log with "failed flags match"
- - With the fix: the mount should succeed
-
+ * The setup instructions assume no access to an existing SSH client-server
pair.
+ - Spin up two Ubuntu Plucky VMs, one of which will be referred to as
sshfs-client and the other of which will be referred to as sshfs-server
+ - Install openssh-server on the server and sshfs on the client
+ - Ensure that the two machines are able to ping each other using a
[machine hostname].local address
+ - Generate an SSH key on the client and copy it into the
~/.ssh/authorized_keys directory on the server
+ - Ensure that the client can SSH into the server without a password prompt
(using the key)
+ - Uncomment the "user_allow_other" line in sshfs-client's /etc/fuse.conf
+ - Create a mountpoint directory somewhere inside sshfs-client's home
directory
+ - Verify that a manual sshfs mount using `sshfs -o
_netdev,user,idmap=user,transform_symlinks,allow_other,default_permissions,uid=1000,gid=1000
username@sshfs-server:/path/to/directory /home/username/mountpoint` works, and
then unmount the newly created mount
+ - Add the entry `username@sshfs-server:/path/to/directory
/home/username/mountpoint fuse.sshfs
_netdev,user,idmap=user,transform_symlinks,allow_other,default_permissions,uid=1000,gid=1000
0 0` to sshfs-client's /etc/fstab
+ - Attempt to mount the new fstab mount entry with `mount -a`
+ - Without the fix: the mount will fail with a permission denied error and
generate an AppArmor log with "failed flags match"
+ - With the fix: the mount should succeed
[ Where problems could occur ]
Adding the mount flag to the mount rules loosens confinement on a
profile. However, if a user manually modified the installed profiles,
then the package upgrade would cause conflicts, and rejection of the
incoming changes (either by hand during an interactive upgrade or
automatically during an batch unattended upgrade) would result in end
users not getting the packaged fix.
[ Other Info ]
--------Original bug report:
My sshfs mounts from /etc/fstab stopped working after upgrading to Plucky.
This is the line from my fstab:
```
[email protected]:/datastore/media /media/Media fuse.sshfs
_netdev,user,idmap=user,transform_symlinks,port=22,allow_other,default_permissions,uid=1000,gid=1000
0 0
```
And I uncommented `user_allow_other` in `/etc/fuse.conf`.
Usually I'm able to mount this with `mount -a`, or by simply clicking
the mount in Gnome Files (Nautilus). But now I get:
```
mount -a
fusermount3: mount failed: Permission denied
```
If I add `sudo` to the mount command, I get:
```
sudo mount -a
read: Connection reset by peer
```
But strangely, the mount works just fine if I mount using `sshfs`:
```
sshfs -o
_netdev,user,idmap=user,transform_symlinks,port=22,allow_other,default_permissions,uid=1000,gid=1000
[email protected]:/datastore/media /media/Media
```
I suspect it has something to do with apparmor, because the following
log appears when I attempt a mount via Nautilus:
```
sudo journalctl -xe | grep DENIED
mei 27 13:58:51 saibot kernel: audit: type=1400 audit(1748347131.297:5484):
apparmor="DENIED" operation="mount" class="mount" info="failed flags match"
error=-13 profile="fusermount3" name="/media/Media/" pid=69641
comm="fusermount3" fstype="fuse"
srcname="[email protected]:/datastore/media" flags="rw, nosuid,
nodev, noexec"
```
** Changed in: apparmor (Ubuntu Questing)
Status: New => Fix Released
** Changed in: apparmor (Ubuntu Plucky)
Status: New => In Progress
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Touch seeded packages, which is subscribed to apparmor in Ubuntu.
https://bugs.launchpad.net/bugs/2111807
Title:
Plucky broke fstab sshfs mounts, which depend on fusermount
Status in apparmor package in Ubuntu:
Fix Released
Status in apparmor source package in Plucky:
In Progress
Status in apparmor source package in Questing:
Fix Released
Bug description:
[ Impact ]
sshfs mounts specified in /etc/fstab would fail to mount when a mount
of all filesystems specified in the fstab was attempted with mount -a.
This was due to a missing noexec mount flag specification in the mount
rules of fusermount3's profile.
[ Test Plan ]
* The setup instructions assume no access to an existing SSH client-server
pair.
- Spin up two Ubuntu Plucky VMs, one of which will be referred to as
sshfs-client and the other of which will be referred to as sshfs-server
- Install openssh-server on the server and sshfs on the client
- Ensure that the two machines are able to ping each other using a
[machine hostname].local address
- Generate an SSH key on the client and copy it into the
~/.ssh/authorized_keys directory on the server
- Ensure that the client can SSH into the server without a password prompt
(using the key)
- Uncomment the "user_allow_other" line in sshfs-client's /etc/fuse.conf
- Create a mountpoint directory somewhere inside sshfs-client's home
directory
- Verify that a manual sshfs mount using `sshfs -o
_netdev,user,idmap=user,transform_symlinks,allow_other,default_permissions,uid=1000,gid=1000
username@sshfs-server:/path/to/directory /home/username/mountpoint` works, and
then unmount the newly created mount
- Add the entry `username@sshfs-server:/path/to/directory
/home/username/mountpoint fuse.sshfs
_netdev,user,idmap=user,transform_symlinks,allow_other,default_permissions,uid=1000,gid=1000
0 0` to sshfs-client's /etc/fstab
- Attempt to mount the new fstab mount entry with `mount -a`
- Without the fix: the mount will fail with a permission denied error and
generate an AppArmor log with "failed flags match"
- With the fix: the mount should succeed
[ Where problems could occur ]
Adding the mount flag to the mount rules loosens confinement on a
profile. However, if a user manually modified the installed profiles,
then the package upgrade would cause conflicts, and rejection of the
incoming changes (either by hand during an interactive upgrade or
automatically during an batch unattended upgrade) would result in end
users not getting the packaged fix.
[ Other Info ]
--------Original bug report:
My sshfs mounts from /etc/fstab stopped working after upgrading to Plucky.
This is the line from my fstab:
```
[email protected]:/datastore/media /media/Media fuse.sshfs
_netdev,user,idmap=user,transform_symlinks,port=22,allow_other,default_permissions,uid=1000,gid=1000
0 0
```
And I uncommented `user_allow_other` in `/etc/fuse.conf`.
Usually I'm able to mount this with `mount -a`, or by simply clicking
the mount in Gnome Files (Nautilus). But now I get:
```
mount -a
fusermount3: mount failed: Permission denied
```
If I add `sudo` to the mount command, I get:
```
sudo mount -a
read: Connection reset by peer
```
But strangely, the mount works just fine if I mount using `sshfs`:
```
sshfs -o
_netdev,user,idmap=user,transform_symlinks,port=22,allow_other,default_permissions,uid=1000,gid=1000
[email protected]:/datastore/media /media/Media
```
I suspect it has something to do with apparmor, because the following
log appears when I attempt a mount via Nautilus:
```
sudo journalctl -xe | grep DENIED
mei 27 13:58:51 saibot kernel: audit: type=1400 audit(1748347131.297:5484):
apparmor="DENIED" operation="mount" class="mount" info="failed flags match"
error=-13 profile="fusermount3" name="/media/Media/" pid=69641
comm="fusermount3" fstype="fuse"
srcname="[email protected]:/datastore/media" flags="rw, nosuid,
nodev, noexec"
```
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https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/2111807/+subscriptions
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