Because a container is only as isolated from the host as you want it to be.
Suppose you run a container and mount the entire filesystem into it. If that container is running as root, it can then read and write anything it likes (including password databases and /etc/sudo)
So what? If I mount / in the container and choose to run it as root that's my business. Why would the containerization engine second-guess what I'm doing?
How would you like it if sudo told you "I can't let you be root, you could read and write anything you like, including password databases and /etc/sudo"?
Nothing to stop running podman containers with full root access by creating & running them as root, you run them as whatever user you want. I've done it to troubleshoot containers on more than one occasion, usually when I want to play with VPN or privileged ports but too lazy to do it proper. The end goal for a lot of ppl, including myself, is to run as many things as non-root as possible. Why? Best practices around security have you give a service the minimal access & resources it needs to do it's tasks. Some people allow traffic from the internet to their containers & they probably feel a little bit safer running those programs as non-root since it can create an extra layer that may need to be broken to fully compromise a system.
The point is to minimize privilege to the least possible - not to make it impossible to create higher privileged containers. If a container doesn't need to get direct raw hardware access, manage low ports on the host network, etc. then why should I give it root and let it be able to do those things? Mapping it to a user, controlling what resources it has access to, and restricting it's capabilities means that in the event that my container gets compromised, my entire host isn't necessarily screwed.
We're not saying "sudo shouldn't be able to run as root" but that "by default things shouldn't be run with sudo - and you need a compelling reason to swap over when you do"
Because a container is only as isolated from the host as you want it to be.
Suppose you run a container and mount the entire filesystem into it. If that container is running as root, it can then read and write anything it likes (including password databases and /etc/sudo)
So what? If I mount / in the container and choose to run it as root that's my business. Why would the containerization engine second-guess what I'm doing?
How would you like it if sudo told you "I can't let you be root, you could read and write anything you like, including password databases and /etc/sudo"?
Nothing to stop running podman containers with full root access by creating & running them as root, you run them as whatever user you want. I've done it to troubleshoot containers on more than one occasion, usually when I want to play with VPN or privileged ports but too lazy to do it proper. The end goal for a lot of ppl, including myself, is to run as many things as non-root as possible. Why? Best practices around security have you give a service the minimal access & resources it needs to do it's tasks. Some people allow traffic from the internet to their containers & they probably feel a little bit safer running those programs as non-root since it can create an extra layer that may need to be broken to fully compromise a system.
The point is to minimize privilege to the least possible - not to make it impossible to create higher privileged containers. If a container doesn't need to get direct raw hardware access, manage low ports on the host network, etc. then why should I give it root and let it be able to do those things? Mapping it to a user, controlling what resources it has access to, and restricting it's capabilities means that in the event that my container gets compromised, my entire host isn't necessarily screwed.
We're not saying "sudo shouldn't be able to run as root" but that "by default things shouldn't be run with sudo - and you need a compelling reason to swap over when you do"