Commit Graph

6 Commits (2531065d1010424866ef764bbea3aa3708cb49b2)

Author SHA1 Message Date
Percy Wegmann 4b525fdda0 ssh/tailssh: only chdir incubator process to user's homedir when necessary and possible
Instead of changing the working directory before launching the incubator process,
this now just changes the working directory after dropping privileges, at which
point we're more likely to be able to enter the user's home directory since we're
running as the user.

For paths that use the 'login' or 'su -l' commands, those already take care of changing
the working directory to the user's home directory.

Fixes #13120

Signed-off-by: Percy Wegmann <percy@tailscale.com>
3 months ago
Percy Wegmann 7d83056a1b ssh/tailssh: fix SSH on busybox systems
This involved the following:

1. Pass the su command path as first of args in call to unix.Exec to make sure that busybox sees the correct program name.
   Busybox is a single executable userspace that implements various core userspace commands in a single binary. You'll
   see it used via symlinking, so that for example /bin/su symlinks to /bin/busybox. Busybox knows that you're trying
   to execute /bin/su because argv[0] is '/bin/su'. When we called unix.Exec, we weren't including the program name for
   argv[0], which caused busybox to fail with 'applet not found', meaning that it didn't know which command it was
   supposed to run.
2. Tell su to whitelist the SSH_AUTH_SOCK environment variable in order to support ssh agent forwarding.
3. Run integration tests on alpine, which uses busybox.
4. Increment CurrentCapabilityVersion to allow turning on SSH V2 behavior from control.

Fixes #12849

Signed-off-by: Percy Wegmann <percy@tailscale.com>
3 months ago
Percy Wegmann 730f0368d0 ssh/tailssh: replace incubator process with su instead of running su as child
This allows the SSH_AUTH_SOCK environment variable to work inside of
su and agent forwarding to succeed.

Fixes #12467

Signed-off-by: Percy Wegmann <percy@tailscale.com>
5 months ago
Percy Wegmann d7fdc01f7f ssh/tailssh: check IsSELinuxEnforcing in tailscaled process
Checking in the incubator as this used to do fails because
the getenforce command is not on the PATH.

Updates #12442

Signed-off-by: Percy Wegmann <percy@tailscale.com>
5 months ago
Percy Wegmann 08a9551a73 ssh/tailssh: fall back to using su when no TTY available on Linux
This allows pam authentication to run for ssh sessions, triggering
automation like pam_mkhomedir.

Updates #11854

Signed-off-by: Percy Wegmann <percy@tailscale.com>
6 months ago
Percy Wegmann 843afe7c53 ssh/tailssh: add integration test
Updates tailscale/corp#11854

Signed-off-by: Percy Wegmann <percy@tailscale.com>
7 months ago