Ubuntu14.04 普通用户无法通过 sshkey 登陆

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这是一个创建于 3013 天前的主题，其中的信息可能已经有所发展或是发生改变。

如题。目前的基本情况是：

本地：

OS:OS X 10.11.6
用户名:fourstring

服务器:

OS:Ubuntu14.04 x64 LTS
用户名:git(想要建立 git 远程仓库)

我新建了 git 用户，然后在/home/git下建立.ssh目录，设置权限为git:git 0700，并在.ssh目录下运行ssh-keygen，生成公私钥，将公钥命名为authorized_keys，设置权限git:git 0600。将私钥复制回本地，本地建立 ssh 配置，并且授予私钥权限 0600 。

之后，尝试使用 ssh 命令连接服务器，连接被拒绝。

我做的几点排查：

auth.log 没有任何验证失败信息
/etc/ssh/sshd_config中已经设置了

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile      %h/.ssh/authorized_keys

确认各个文件权限完全正确
git 用户没有加入 /sbin/nologin(测试用)
由于是 ubuntu 不存在 selinux
root 用户可以正常登陆

运行ssh hexo(配置中的 Host 名) -vvv信息如下:

OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /Users/fourstring/.ssh/config
debug1: /Users/fourstring/.ssh/config line 1: Applying options for hexo
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to xxx port xxx.
debug1: Connection established.
debug1: identity file /Users/fourstring/.ssh/hexo type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/fourstring/.ssh/hexo-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.6
debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.6 pat OpenSSH_6.6.1* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to xxx as 'git'
debug3: put_host_port: xxx
debug3: hostkeys_foreach: reading file "/Users/fourstring/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/fourstring/.ssh/known_hosts:22
debug3: load_hostkeys: loaded 1 keys from xxx
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: [email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],[email protected],ssh-ed25519,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1,[email protected],[email protected],[email protected],[email protected],hmac-md5,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1,[email protected],[email protected],[email protected],[email protected],hmac-md5,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: [email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ssh-ed25519
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,[email protected],[email protected],[email protected],aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,[email protected],[email protected],[email protected],aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-md5,hmac-sha1,[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-md5,hmac-sha1,[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug1: kex: server->client [email protected] <implicit> none
debug1: kex: client->server [email protected] <implicit> none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:jGsXPrH3Cl2EWrBRzd4rr72jDeWKugYGPySGAMFL1mU
debug3: put_host_port: xxx
debug3: put_host_port: xxx
debug3: hostkeys_foreach: reading file "/Users/fourstring/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/fourstring/.ssh/known_hosts:22
debug3: load_hostkeys: loaded 1 keys from xxx
debug3: hostkeys_foreach: reading file "/Users/fourstring/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/fourstring/.ssh/known_hosts:22
debug3: load_hostkeys: loaded 1 keys from xxx
debug1: Host 'xxx' is known and matches the ECDSA host key.
debug1: Found key in /Users/fourstring/.ssh/known_hosts:22
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /Users/fourstring/.ssh/hexo (0x7f9f3b013d70), explicit
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/fourstring/.ssh/hexo
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey).

最离奇的是以我自己的了解，我竟然没有从中看出任何连接被拒绝的信息。。。

另外，查找资料说本地用户名须和远程要登陆的用户名一致，但我的实际体验中并非如此。我的root用户就是本地生成sshkey上传到服务器，可以正常登陆。而且从我描述的流程中，可以看出我是在服务器上生成的key然后下载到本地的。

还望各位大神不吝赐教，感谢！

34 条回复 • 2018-04-09 13:08:43 +08:00

sopato

2016-08-09 18:09:32 +08:00

看看 /var/log/auth.log 输出了什么信息给你，根据那个错误信息来检查排错一下呗。

shenqi

2016-08-09 18:09:51 +08:00

不知道。围观下，坐等其他人的回答。

我觉得是露珠描述不清楚。

ipeony

2016-08-09 18:21:35 +08:00 via Android

private key 没加载好？正常是启个 agent ，然后 ssh-add 吧

finian

2016-08-09 18:34:16 +08:00

1. 远程 sshd 改完配置重启了吗？
2. 本地私钥是这个 /Users/fourstring/.ssh/hexo 对吗？

wweir

2016-08-09 19:05:23 +08:00

对 $HOME 目录的权限也有要求，验了么？
之前搞 docker 把 /root 目录共享了一下，也是 ssh 方面出了一大堆问题

fourstring

2016-08-09 19:11:36 +08:00

@sopato auth.log 没有任何错误……而且我还运行过 tail -f /var/run/auth.log ，在连接失败时该日志没有任何变化

fourstring

2016-08-09 19:11:54 +08:00

@shenqi 您觉得是哪里描述不清楚呢？请指出

crazycen

2016-08-09 19:12:26 +08:00 via iPhone

.ssh 目录不需要手动建立，还有，确认你生成 key 的方式是否正确。这是最基本功能，也不可能会出问题！

fourstring

2016-08-09 19:14:15 +08:00

@ipeony .ssh 目录下 config 文件是用 IdentifyFile 选项加载 privatekey 么？如果是的话我应该没有配置错。
另外和能正常登陆的 root 用户的-vvv 比较了一下，好像就只有 debug 信息的最后几行，正常的是
debug2: we sent a publickey packet, wait for reply
之后就收到 auth succeed 的回复然后进入 shell

fourstring

2016-08-09 19:14:57 +08:00

@finian 实际上我没有改过配置，那个配置是默认就有的。我也尝试过重启 sshd ，没有效果。私钥是这个，没有出错。

fourstring

2016-08-09 19:16:06 +08:00

@wweir 我用的是 adduser 命令添加用户，自动建立了主目录，刚刚又去检查了一下，$HOME 的权限是正确的

fourstring

2016-08-09 19:16:40 +08:00

@crazycen 请问.ssh 目录不手动建立该如何建立呢？另外生成 key 的方式是不是运行 ssh-keygen 命令？

crazycen

2016-08-09 19:20:51 +08:00

http://blog.sina.com.cn/s/blog_a0e5bf2c01010h1x.html 参考吧！

larsenlouis

2016-08-09 19:21:11 +08:00

普通用户能用密码登录吗？普通用户的 Home 加密了？如果普通用户 home 目录加密，本机没有登录的情况下， Home 目录没有挂载，只能密码登录。而 root 用户的 home 目录不在加密的目录里。

oxoxoxox

2016-08-09 19:27:10 +08:00

远端 server 的 authorized_keys 权限设置为 644 试试看呢？

fourstring

2016-08-09 19:29:17 +08:00

@larsenlouis 密码可以登录。我用 adduser 命令添加的用户，应该不会自动加密吧？ root 是可以正常访问 git 用户的$home 目录的

fourstring

2016-08-09 19:31:41 +08:00

@oxoxoxox 这个刚刚尝试了一下，貌似并没有什么用。。。/var/run/auth.log 里也没有报权限错误

larsenlouis

2016-08-09 19:33:05 +08:00

@fourstring 加密 home 是安装 ubuntu 系统时选的，你看看 /etc/fstab 有没有 encryptfs 的载点， root 可以正常访问时用 ssh 还是服务器本地，当时服务器本地有没有普通用户登录？

fourstring

2016-08-09 19:36:08 +08:00

@larsenlouis 对，安装 ubuntu 的时候确实会送这个。问题是我是 VPS 啊。。。 root 用 ssh 可以正常访问的。我都进不去服务器本地- -

larsenlouis

2016-08-09 19:38:54 +08:00

@fourstring 有些供应商会在虚拟机的控制台上模拟本地终端，你用普通用户登录后用`w`命令看看有没有 tty 的 session

fourstring

2016-08-09 19:41:44 +08:00

@larsenlouis 没有啊- -都是 pts ？

larsenlouis

2016-08-09 20:04:18 +08:00

@fourstring 贴一下本地的.ssh/config 和服务器的 sshd_config
实在不知道是什么问题这个时候就要 sudo apt remove openssh-server --purge && rm -rf ~/.ssh/，祭出此文，重装。 https://help.ubuntu.com/community/SSH/OpenSSH/Keys

客户端本地生成密匙， ssh-copy-id(不知道 macOS 有没有)上传 publickey ，再改本地.ssh/config ，再改服务器 sshd_config 关闭密码登录和禁止 root 登录，最后装上 fail2ban 。

fourstring

2016-08-09 20:07:02 +08:00

@larsenlouis sshd_config:
# Package generated configuration file
# See the sshd_config(5) manpage for details

# What ports, IPs and protocols we listen for
Port 63842
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
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
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes

# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 1024

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication:
LoginGraceTime 120
PermitRootLogin yes
StrictModes yes

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile %h/.ssh/authorized_keys

# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Change to no to disable tunnelled clear text passwords
PasswordAuthentication no

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

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes

X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
#UseLogin no

#MaxStartups 10:30:60
#Banner /etc/issue.net

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*

Subsystem sftp /usr/lib/openssh/sftp-server

# 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

ssh config ：
Host hexo
HostName xxx
Port 63842
User git
IdentityFile ~/.ssh/hexo

fourstring

2016-08-09 20:07:40 +08:00

@larsenlouis 另外由客户端生成密钥和服务端生成密钥都试过，均失败

abmin521

2016-08-09 20:15:28 +08:00 via Android

试一下 ssh localhost ？

fourstring

2016-08-09 20:20:46 +08:00

@abmin521 为什么要这么用。。。？是在服务器上么？

abmin521

2016-08-09 20:22:24 +08:00 via Android

@fourstring 不是服务器要登陆 root 的机器有些服务器可能有限制

abmin521

2016-08-09 20:22:49 +08:00 via Android

看错了是服务器

hsyu53

2016-08-09 20:33:25 +08:00 via Android

印象中是在本地生产密钥，再将公钥拷贝到服务端

larsenlouis

2016-08-09 20:36:08 +08:00

@fourstring UserPAM 之后放 subsystem ，而且 subsystem 在配置最后，没有其他配置。应该是这个的问题，另外 sftp 组里有哪些用户？

fourstring

2016-08-09 20:44:57 +08:00

@larsenlouis 我刚刚用 VNC 连接，开启 sshd -d 看了一下 debug 信息，还请您看一下？（只有图片，没法复制出来- -）

另外按您说的那样改了，也没有用= =

fourstring

2016-08-09 20:50:42 +08:00

@larsenlouis ヾ(｡｀Д´｡)！被这个问题坑了一下午，我有点想爆粗口了。。。
我在服务端又重新生成了一对密钥，然后把私钥下载回本地，一开始仍然失败。
当我把私钥名字从 hexo 改掉之后……连上了！连上了！神 TM 连上了……

abmin521

2016-08-09 21:22:50 +08:00 via Android

呵呵上面的当我没说

winstars

2018-04-09 13:08:43 +08:00

@fourstring #32 同学，我也是一样的问题，私钥名改掉是什么意思？