SSH connection asks for password connecting to Docker container [closed] - linux

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I've already looked for similar questions and tried changing several things in my configuration but couldn't come up with a solution.
I'm trying to connecting via SSH to a Docker container, here's the Dockerfile:
FROM ubuntu
RUN apt-get update && \
apt-get install -y openssh-server
RUN useradd remote_user && \
echo "remote_user:test1234" | chpasswd && \
mkdir /home/remote_user/.ssh -p && \
chmod 700 /home/remote_user/.ssh && \
mkdir -p -m0755 /var/run/sshd
COPY id_rsa.pub /home/remote_user/.ssh/authorized_keys
RUN chown remote_user:remote_user -R /home/remote_user && \
chmod 600 /home/remote_user/.ssh/authorized_keys
RUN apt-get install -y php php-mbstring php-xml php-bcmath php-fpm && \
apt-get install -y composer && apt-get install -y vim
RUN apt-get install -y nginx
CMD /usr/sbin/sshd -D
Once I try to connect to the container as "remote_user" with ssh -Tv remote_user#staging.local (where "staging.local" is the container IP) I get this message:
...
...
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,sk-ssh-ed25519#openssh.com,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256#openssh.com>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: /home/xxx/.ssh/id_rsa RSA SHA256:5QNPe89pdQp+tgE61N9YPaIJEs8QR9DxaChmStfvzBU agent
debug1: Authentications that can continue: publickey,password
debug1: Offering public key: xxx#xxx RSA SHA256:C+VWlGUd4mVywHnh8JWtjL0gmO8cuqUEs4YYCbQGvaE agent
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/xxx/.ssh/id_dsa
debug1: Trying private key: /home/xxx/.ssh/id_ecdsa
debug1: Trying private key: /home/xxx/.ssh/id_ecdsa_sk
debug1: Trying private key: /home/xxx/.ssh/id_ed25519
debug1: Trying private key: /home/xxx/.ssh/id_ed25519_sk
debug1: Trying private key: /home/xxx/.ssh/id_xmss
debug1: Next authentication method: password
remote_user#staging.local's password:
As you can see it can't connect and is asking for the password.
If I ls -ll .ssh folder files in my host machine I have this:
-rw------- 1 xxx xxx 2610 Jan 3 12:08 id_rsa
-rw-r--r-- 1 xxx xxx 577 Jan 3 12:08 id_rsa.pub
-rw-r--r-- 1 xxx xxx 222 Jan 3 12:25 known_hosts
If I docker exec into the container as root user and see permissions of /home/remote_user/.ssh I have:
home folder permissions:
drwxr-xr-x 1 root root 4096 Jan 3 11:22 home
remote_user folder permissions:
drwxr-xr-x 1 remote_user remote_user 4096 Jan 3 11:22 remote_user
.ssh folder permissions:
drwx------ 1 remote_user remote_user 4096 Jan 3 11:22 .ssh
authorized_keys file permissions:
-rw------- 1 remote_user remote_user 577 Jan 3 11:08 authorized_keys

Answer 1

Try changing the permissions for the /home/remote_user/.ssh/authorized_keys to 400 instead of 600. Other than that, I don't see any difference between my own setup.
p.s.
My setup runs with ubuntu 18.04 so maybe they changed something since then.

Answer 2

It should work if you forward the port :
docker run -p 222:22 your-image
then :
ssh -p 222 remote_user#localhost