this post was submitted on 06 May 2024
33 points (92.3% liked)

Linux

48310 readers
645 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

Related Communities

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

founded 5 years ago
MODERATORS
AgreeableLandscape@lemmy.ml
nooter692@lemmy.ml
MarcellusDrum@lemmy.ml
cypherpunks@lemmy.ml
cyclohexane@lemmy.ml
d3Xt3r@lemmy.nz
33
SSH login without user name? (docs.gitlab.com)
submitted 6 months ago by Aarkon@feddit.de to c/linux@lemmy.ml
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
[–] bbbhltz@beehaw.org 1 points 6 months ago

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?

Yes.

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?

Most of this can be found reading through different Git docs, whether from GitHub, GitLab, Codeberg, Gitea, etc. When using Git you can use different keys for different repos/forges and each has a defined pair, similar to accessing different SSH servers that require specific key pairs. I do understand your questions, but I lack the finesse to explain it since I really only use SSH and Git for my blog and not for anything too complicated.