Centos7 密钥对登陆（适用于群晖DSM）

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1.生成证书

此处证书使用swack用户生成

注：不要使用root生成证书，因为我们后面会禁用root登陆

[swack@localhost ~]$ ssh-keygen -t rsa -b 2048 -C "swack_test"
Generating public/private rsa key pair.
Enter file in which to save the key (/home/swack/.ssh/id_rsa):
Created directory '/home/swack/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/swack/.ssh/id_rsa.
Your public key has been saved in /home/swack/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:BRidXhVBsAYWEt73wp8KzQa52vXLMKyvyEpuV8NGd44 swack_test
The key's randomart image is:
+---[RSA 2048]----+
| +==o.+=o |
| ..+oo.. |
| ....= |
| o... |
| oS.o+. |
| =Eo.. |
| . oo.O o |
| o...+ = * |
| .oo+ +oo +. |
+----[SHA256]-----+

执行完毕后，会在用户home目录生成.ssh目录，其下生成两个证书文件

• 公钥文件：.ssh/id_rsa.pub
• 密钥文件：.ssh/id_rsa

2.配置ssh

修改 /etc/ssh/sshd_config 可以配置ssh的相关参数（需要root权限）

[root@localhost swack]# vim /etc/ssh/sshd_config

为了使得系统安全性进一步提高，我们做一下更改

• 修改默认ssh的默认端口22到8022（此处端口可自定义）
• 禁用密码认证进制
• 禁止root权限登陆
• 使用密钥对登陆

#       $OpenBSD: sshd_config,v 1.100 2016/08/15 12:32:04 naddy Exp $

# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/local/bin:/usr/bin

# 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.

# If you want to change the port on a SELinux system, you have to tell
# SELinux about this change.
# semanage port -a -t ssh_port_t -p tcp #PORTNUMBER
#
Port 8022
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::

HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key

# Ciphers and keying
#RekeyLimit default none

# Logging
#SyslogFacility AUTH
SyslogFacility AUTHPRIV
#LogLevel INFO

# Authentication:

#LoginGraceTime 2m
PermitRootLogin no
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10

PubkeyAuthentication yes

# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
# but this is overridden so installations will only check .ssh/authorized_keys
AuthorizedKeysFile      .ssh/authorized_keys

#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
PasswordAuthentication no

# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes
ChallengeResponseAuthentication no

# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
#KerberosUseKuserok yes

# GSSAPI options
GSSAPIAuthentication yes
GSSAPICleanupCredentials no
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no
#GSSAPIEnablek5users 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'.
# WARNING: 'UsePAM no' is not supported in Red Hat Enterprise Linux and may cause several
# problems.
UsePAM yes

#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation sandbox
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#ShowPatchLevel no
#UseDNS yes
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none

# no default banner path
#Banner none

# Accept locale-related environment variables
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS

# override default of no subsystems
Subsystem       sftp    /usr/libexec/openssh/sftp-server

# Example of overriding settings on a per-user basis
#Match User anoncvs
#       X11Forwarding no
#       AllowTcpForwarding no
#       PermitTTY no
#       ForceCommand cvs server

此处如下修改：

• Port 8022
• PasswordAuthentication no
• PermitRootLogin no
• PubkeyAuthentication yes

重启ssh服务

[root@localhost swack]# systemctl restart sshd.service

2.配置公钥

在.ssh目录，新建一个文件

• 证书验证文件：.ssh/authorized_keys

将公钥证书文件写到证书验证文件里

[swack@localhost ~]$ touch .ssh/authorized_keys
[swack@localhost ~]$ cat /home/swack/.ssh/id_rsa.pub >> /home/swack/.ssh/authorized_keys
[swack@localhost ~]$ cat .ssh/authorized_keys
ssh-rsa
AAAAB3NzaC1yc2EAAAA...
swack_test

注：这里需要把允许登陆的centos7服务的终端的公钥id_rsa.pub添加到authorized_keys文件中

3.设置 .ssh 目录权限

[swack@localhost ~]$ chmod -R 700 .ssh
[swack@localhost ~]$ chmod 600 .ssh/authorized_keys

4.测试登陆（基于windows 10）

需要生成客户本地主机的公钥，并把密钥写入服务器的authorized_keys文件中

ssh登陆

此处使用的工具是GitBash

下载地址：WinSCP-5.15-Setup.exe

使用 ssh -p 8022 swack@192.168.241.3 登陆

sftp登陆

此处我们使用的工具是WinSCP

下载地址：Git-2.15.1.2-64-bit.exe

在WinSCP的高级设置里选择密钥文件