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>
This commit is contained in:
Percy Wegmann
2024-08-05 17:09:34 -05:00
committed by Percy Wegmann
parent 7675c3ebf2
commit 7d83056a1b
5 changed files with 59 additions and 38 deletions

View File

@@ -117,7 +117,8 @@ sshintegrationtest: ## Run the SSH integration tests in various Docker container
echo "Testing on ubuntu:focal" && docker build --build-arg="BASE=ubuntu:focal" -t ssh-ubuntu-focal ssh/tailssh/testcontainers && \
echo "Testing on ubuntu:jammy" && docker build --build-arg="BASE=ubuntu:jammy" -t ssh-ubuntu-jammy ssh/tailssh/testcontainers && \
echo "Testing on ubuntu:mantic" && docker build --build-arg="BASE=ubuntu:mantic" -t ssh-ubuntu-mantic ssh/tailssh/testcontainers && \
echo "Testing on ubuntu:noble" && docker build --build-arg="BASE=ubuntu:noble" -t ssh-ubuntu-noble ssh/tailssh/testcontainers
echo "Testing on ubuntu:noble" && docker build --build-arg="BASE=ubuntu:noble" -t ssh-ubuntu-noble ssh/tailssh/testcontainers && \
echo "Testing on alpine:latest" && docker build --build-arg="BASE=alpine:latest" -t ssh-alpine-latest ssh/tailssh/testcontainers
help: ## Show this help
@echo "\nSpecify a command. The choices are:\n"