我正在 CI 中设置我的虚拟机，以便可以测试使用 ssh 的脚本，例如使用ssh localhost。
但问题是，我的公钥（在 中~/.ssh/id_rsa.pub）一直被拒绝，即使它已被添加到 中~/.ssh/authorized_keys。问题是，在调试模式下运行不会给出具体原因。
具体来说，我正在按如下方式设置运行 Ubuntu 20.04.2 LTS 的虚拟机：
sudo apt-get install openssh-server
ssh-keygen -t rsa -q -f "$HOME/.ssh/id_rsa" -N ""
cat "$HOME/.ssh/id_rsa.pub" >> "$HOME/.ssh/authorized_keys"
chmod g-w "$HOME"
chmod 700 "$HOME/.ssh"
chmod 600 "$HOME/.ssh/authorized_keys"
ssh -o "StrictHostKeyChecking accept-new" -v localhost "uname -r"
后一个命令给了我输出。
OpenSSH_8.2p1 Ubuntu-4ubuntu0.1, OpenSSL 1.1.1f 31 Mar 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to localhost [::1] port 22.
debug1: Connection established.
debug1: identity file /home/runner/.ssh/id_rsa type 0
debug1: identity file /home/runner/.ssh/id_rsa-cert type -1
debug1: identity file /home/runner/.ssh/id_dsa type -1
debug1: identity file /home/runner/.ssh/id_dsa-cert type -1
debug1: identity file /home/runner/.ssh/id_ecdsa type -1
debug1: identity file /home/runner/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/runner/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/runner/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/runner/.ssh/id_ed25519 type -1
debug1: identity file /home/runner/.ssh/id_ed25519-cert type -1
debug1: identity file /home/runner/.ssh/id_ed25519_sk type -1
debug1: identity file /home/runner/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/runner/.ssh/id_xmss type -1
debug1: identity file /home/runner/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.2p1 Ubuntu-4ubuntu0.1
debug1: match: OpenSSH_8.2p1 Ubuntu-4ubuntu0.1 pat OpenSSH* compat 0x04000000
debug1: Authenticating to localhost:22 as 'runner'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:OuD1nXO8ACrHcMnbqRxbdHlXr+4S1fKUAwMqxGEx3fw
Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts.
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/runner/.ssh/id_rsa RSA SHA256:K4wwThvI/q9Na47DI24BKpus4t0ZZXOzJ+esYzukD1c
debug1: Will attempt key: /home/runner/.ssh/id_dsa
debug1: Will attempt key: /home/runner/.ssh/id_ecdsa
debug1: Will attempt key: /home/runner/.ssh/id_ecdsa_sk
debug1: Will attempt key: /home/runner/.ssh/id_ed25519
debug1: Will attempt key: /home/runner/.ssh/id_ed25519_sk
debug1: Will attempt key: /home/runner/.ssh/id_xmss
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,[email protected],ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected]>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: /home/runner/.ssh/id_rsa RSA SHA256:K4wwThvI/q9Na47DI24BKpus4t0ZZXOzJ+esYzukD1c
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/runner/.ssh/id_dsa
debug1: Trying private key: /home/runner/.ssh/id_ecdsa
debug1: Trying private key: /home/runner/.ssh/id_ecdsa_sk
debug1: Trying private key: /home/runner/.ssh/id_ed25519
debug1: Trying private key: /home/runner/.ssh/id_ed25519_sk
debug1: Trying private key: /home/runner/.ssh/id_xmss
debug1: Next authentication method: password
debug1: read_passphrase: can't open /dev/tty: No such device or address
debug1: Authentications that can continue: publickey,password
Permission denied, please try again.
debug1: read_passphrase: can't open /dev/tty: No such device or address
debug1: Authentications that can continue: publickey,password
Permission denied, please try again.
debug1: read_passphrase: can't open /dev/tty: No such device or address
debug1: Authentications that can continue: publickey,password
debug1: No more authentication methods to try.
runner@localhost: Permission denied (publickey,password).
可以看到，ssh 最终会尝试使用密码登录，但该密码在此虚拟机上未配置。我甚至不想尝试，而是直接接受我的 ssh id_rsa.pub。
的输出cat /etc/ssh/sshd_config如下：
# $OpenBSD: sshd_config,v 1.103 2018/04/09 20:41:22 tj Exp $
# This is the sshd server system-wide configuration file. See
# sshd_config(5) for more information.
# This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin
# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented. Uncommented options override the
# default value.
Include /etc/ssh/sshd_config.d/*.conf
#Port 22
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_ecdsa_key
#HostKey /etc/ssh/ssh_host_ed25519_key
# Ciphers and keying
#RekeyLimit default none
# Logging
#SyslogFacility AUTH
#LogLevel INFO
# Authentication:
#LoginGraceTime 2m
#PermitRootLogin prohibit-password
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10
#PubkeyAuthentication yes
# Expect .ssh/authorized_keys2 to be disregarded by default in future.
#AuthorizedKeysFile .ssh/authorized_keys .ssh/authorized_keys2
#AuthorizedPrincipalsFile none
#AuthorizedKeysCommand none
#AuthorizedKeysCommandUser nobody
# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes
# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication yes
#PermitEmptyPasswords no
# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no
# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no
# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication. Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes
#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
PrintMotd no
#PrintLastLog yes
#TCPKeepAlive yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS no
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none
# no default banner path
#Banner none
# Allow client to pass locale environment variables
AcceptEnv LANG LC_*
# override default of no subsystems
Subsystem sftp /usr/lib/openssh/sftp-server
# Example of overriding settings on a per-user basis
#Match User anoncvs
# X11Forwarding no
# AllowTcpForwarding no
# PermitTTY no
# ForceCommand cvs server
最后
grep 'sshd' /var/log/auth.log
给出
Mar 10 13:41:18 fv-az209-106 sshd[2052]: Authentication refused: bad ownership or modes for directory /home/runner
Mar 10 13:41:18 fv-az209-106 sshd[2052]: Failed password for runner from ::1 port 39984 ssh2
Mar 10 13:41:18 fv-az209-106 sshd[2052]: Failed password for runner from ::1 port 39984 ssh2
Mar 10 13:41:18 fv-az209-106 sshd[2052]: Connection closed by authenticating user runner ::1 port 39984 [preauth]