Bug#1051710: Cannot use Ctrl-C to interrupt remote command with ControlMaster=auto

[Giovanni Mascellani <gio@debian.org>]

Package: openssh-client
Version: 1:9.4p1-1
Severity: normal

My SSH is configured with these directives:

ControlMaster auto
ControlPath ~/.ssh/control/%r@%h:%p.sock
ControlPersist yes

Suppose I connect to some host and launch a command potentially running for a
long or infinite time:

$ ssh host tail -F some/file

Up to version 1:9.3p2-1 I could stop the remote command and the SSH process
pressing Ctrl-C (i.e., by sending SIGINT to the SSH process). This doesn't work
any more. It works instead if I disable the control session:

$ ssh -o ControlMaster=no host tail -F some/file

Thanks for maintaining the package, Giovanni.


-- System Information:
Debian Release: trixie/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.4.0-1-amd64 (SMP w/12 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=it_IT.utf8, LC_CTYPE=it_IT.utf8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages openssh-client depends on:
ii  adduser           3.137
ii  libc6             2.37-8
ii  libedit2          3.1-20221030-2
ii  libfido2-1        1.13.0-1+b1
ii  libgssapi-krb5-2  1.20.1-3
ii  libselinux1       3.5-1
ii  libssl3           3.0.10-1
ii  passwd            1:4.13+dfsg1-1+b1
ii  zlib1g            1:1.2.13.dfsg-3

Versions of packages openssh-client recommends:
ii  xauth  1:1.1.2-1

Versions of packages openssh-client suggests:
pn  keychain      <none>
pn  libpam-ssh    <none>
pn  monkeysphere  <none>
ii  ssh-askpass   1:1.2.4.1-16

-- no debconf information