execve from NetworkManager fails - wrong path in app-armor profile?

[Christopher J. Ruwe]

Linux <hostname> 6.8.0-31-generic #31-Ubuntu SMP PREEMPT_DYNAMIC Sat Apr 20 00:40:06 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

```/etc/os-release
PRETTY_NAME="Ubuntu 24.04 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=noble
LOGO=ubuntu-logo
```

```/etc/apparmor.d/sbin.dhclient
[...]
  # Support the new executable helper from NetworkManager.
  /usr/lib/NetworkManager/nm-dhcp-helper Pxrm,
  signal (receive) peer=/usr/lib/NetworkManager/nm-dhcp-helper,
[...]
```

Starting network manager results in
```
/var/log/syslog:2024-04-28T13:35:22.453634+02:00 <hostname> dhclient[<pid>]: execve (/usr/libexec/nm-dhcp-helper, ...): Permission denied
```

`/usr/lib/NetworkManager/nm-dhcp-helper` does not exist on the system.

[Seth Arnold (seth-arnold)]

Hello Christopher, thanks for the bug report. Note that due to ISC stepping back from their DHCP packages, we've switched to dhcpcd as the "default" dhcp client. Probably a patch to fix this would be accepted, but it might not be anybody's priority to work on it.

Thanks

[Christopher J. Ruwe (cruwe)]

Hi Seth,

sorry to reply that late, had been rather occupied @dayjob. Thanks for your explanation. Th system I noticed the problem on is a box which I steadily bump since 20.4, perhaps even since 19.10. I did not notice the change of the default DHCP-client and do not have any particular fondness for the one over the other, so I just changed the DHCP client.

I will not have the time required to implement and accompany a fix for the ISC DHCP-client, regrettably.

In any case, thank you very much for your effort.

[Wayne Walker (lwaynewalker)]

This patch fixed the problem for me.

Simply fixes the path to nm-dhcp-helper on the 4 lines it appears in the apparmor file

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "2064007.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.