Linux

48331 readers

703 users here now

From Wikipedia, the free encyclopedia

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

Rules

Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
No misinformation
No NSFW content
No hate speech, bigotry, etc

Related Communities

Community icon by Alpár-Etele Méder, licensed under CC BY 3.0

founded 5 years ago

MODERATORS

[email protected]

SSH login without user name? (docs.gitlab.com)

submitted 6 months ago by [email protected] to c/[email protected]

23 comments fedilink hide all child comments

I was reading GitLab's documentation (see link) on how to write to a repository from within the CI pipeline and noticed something: The described Docker executor is able to authenticate e.g. against the Git repository with only a private SSH key, being told absolutely nothing about the user's name it is associated with.
If I'm correct, that would mean that technically, I could authenticate to an SSH server without supplying my name if I use a private key?

I know that when I don't supply a user explicitly like ssh user@server or via .ssh/config, the active environment's user is used automatically, that's not what I'm asking.

The public key contains a user name/email address string, I'm aware, is the same information also encoded into the private key as well? If yes, I don't see the need to hand that info to an SSH call. If no, how does the SSH server know which public key it's supposed to use to challenge my private key ownership? It would have to iterate over all saved keys, which sounds rather inefficient to me and potentially unsafe (timing attacks etc.).

I hope I'm somewhat clear, for some reason I find it really hard to phrase this question.

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 3 points 6 months ago (1 children)

Hmm, with a similar technique one could even create git command aliases for running git with specific ssh private keys

[–] [email protected] 5 points 6 months ago

Better than that, git config supports conditional includes, based on a repo URL or path on disk. So you can have a gitconfig per organization or whatever, which specifies an sshCommand and thus an ssh key.