Tries to start sshd on port 1022 even in chroot, crashes if unable

When running do-release-upgrade inside a chroot, it insists on starting an emergency sshd on port 1022. If it’s not possible, for the likely reason that openssh-server is not installed inside the chroot, the upgrade process crashes.

In a chroot environment, starting such an sshd is not needed because there’s supposed to be one outside the chroot which the upgrade process shouldn’t be able to affect; also it’s a security issue because permissions inside the chroot may be lax due to the fact one needs to be root to get into the chroot in the first place (for example, I have an Ubuntu chroot environment on a Debian stable server for experimenting; I’ve given my user sudo NOPASSWD privileges, which is in itself safe but becomes a liability when the port 1022 sshd launches inside the chroot).

Given that the DistUpgrade module already has inside_chroot() detection function, I suggest that the module only perform its _sshMagic() if no chroot is detected. Additionally, I suggest a command-line option to disable the port 1022 sshd if the administrator so desires.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: python3-distupgrade 1:14.10.9
ProcVersionSignature: Ubuntu 3.16.0-25.33-generic 3.16.7
Uname: Linux 3.16.0-25-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.14.7-0ubuntu8
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: KDE
Date: Sat Dec 6 13:27:54 2014
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to utopic on 2014-11-30 (5 days ago)