使用ssh代理转发和libpam-ssh连接到服务器上没有密码的特定用户。
使用ssh代理转发和libpam-ssh连接到服务器上没有密码的特定用户。
提问于 2020-02-22 09:56:13
我正试图实现设置。
- 我可以使用ssh使用RSA密钥连接到我的服务器到用户A。
- 但我不知道如何转发代理和libpam-ssh一起使用。
目标是发出无密码的sudo命令。
我在玩Debian (Buster)。
ssh su
A ------> B:user X ------> B:userY
^ ^
using A's using A's
ssh key ssh key有可能吗？
Feb 22 11:00:11 jeremydev sshd[4050]: Accepted publickey for juniko from 127.0.0.1 port 55484 ssh2: RSA SHA256:N1N2OMouB8WTpQtYEAt69Iar79D3vOdhIHo96kgbDbU
Feb 22 11:00:11 jeremydev sshd[4050]: pam_unix(sshd:session): session opened for user juniko by (uid=0)
Feb 22 11:00:11 jeremydev systemd-logind[513]: New session 100 of user juniko.
Feb 22 11:00:14 jeremydev sudo[4169]: pam_ssh_agent_auth: Beginning pam_ssh_agent_auth for user juniko
Feb 22 11:00:14 jeremydev sudo[4169]: pam_ssh_agent_auth: Attempting authentication: `juniko' as `juniko' using /etc/ssh/sudo_authorized_keys
Feb 22 11:00:14 jeremydev sudo[4169]: pam_ssh_agent_auth: Contacted ssh-agent of user juniko (1000)
Feb 22 11:00:14 jeremydev sudo[4169]: pam_ssh_agent_auth: Failed Authentication: `juniko' as `juniko' using /etc/ssh/sudo_authorized_keys下面是一个连接日志示例：
OpenSSH_8.1p1 Ubuntu-5, OpenSSL 1.1.1d 10 Sep 2019
debug1: Reading configuration data /home/kwaadpepper/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "example.ovh" port 443
debug2: ssh_connect_direct
debug1: Connecting to example.ovh [XXX.XXX.XXX.XXX] port 443.
debug1: Connection established.
debug1: identity file .ssh/id_rsa type 0
debug1: identity file .ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.1p1 Ubuntu-5
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.9p1
debug1: match: OpenSSH_7.9p1 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to example.ovh:443 as 'juniko'
debug3: put_host_port: [example.ovh]:443
debug3: hostkeys_foreach: reading file "/home/kwaadpepper/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/kwaadpepper/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from [example.ovh]:443
debug3: order_hostkeyalgs: prefer hostkeyalgs: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:qWW1mY2LmZVvhYmdR4Z0z6DBLZiS2JdmmxfYu4vUR/A
debug3: put_host_port: [XXX.XXX.XXX.XXX]:443
debug3: put_host_port: [example.ovh]:443
debug3: hostkeys_foreach: reading file "/home/kwaadpepper/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/kwaadpepper/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from [example.ovh]:443
debug3: hostkeys_foreach: reading file "/home/kwaadpepper/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/kwaadpepper/.ssh/known_hosts:2
debug3: load_hostkeys: loaded 1 keys from [XXX.XXX.XXX.XXX]:443
debug1: Host '[example.ovh]:443' is known and matches the ECDSA host key.
debug1: Found key in /home/kwaadpepper/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: .ssh/id_rsa RSA SHA256:N1N2OMouB8WTpQtYEAt69Iar79D3vOdhIHo96kgbDbU explicit agent
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-with-mic,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 public key: .ssh/id_rsa RSA SHA256:N1N2OMouB8WTpQtYEAt69Iar79D3vOdhIHo96kgbDbU explicit agent
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: .ssh/id_rsa RSA SHA256:N1N2OMouB8WTpQtYEAt69Iar79D3vOdhIHo96kgbDbU explicit agent
debug3: sign_and_send_pubkey: RSA SHA256:N1N2OMouB8WTpQtYEAt69Iar79D3vOdhIHo96kgbDbU
debug3: sign_and_send_pubkey: signing using rsa-sha2-512
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to example.ovh ([XXX.XXX.XXX.XXX]:443).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting no-more-sessions@openssh.com
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug3: receive packet: type 4
debug1: Remote: /home/debian/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug3: receive packet: type 4
debug1: Remote: /home/debian/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start
debug1: Requesting authentication agent forwarding.
debug2: channel 0: request auth-agent-req@openssh.com confirm 0
debug3: send packet: type 98
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug3: send packet: type 98
debug1: Sending environment.
debug3: Ignored env GJS_DEBUG_TOPICS
debug3: Ignored env SSH_AUTH_SOCK
debug3: Ignored env SESSION_MANAGER
debug3: Ignored env GNOME_TERMINAL_SCREEN
debug3: Ignored env SSH_AGENT_PID
debug3: Ignored env XDG_CURRENT_DESKTOP
debug1: Sending env LANG = fr_FR.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env XDG_SESSION_CLASS
debug3: Ignored env COLORTERM
debug3: Ignored env QT_IM_MODULE
debug3: Ignored env GPG_AGENT_INFO
debug3: Ignored env DESKTOP_SESSION
debug3: Ignored env USER
debug3: Ignored env XDG_MENU_PREFIX
debug3: Ignored env HOME
debug3: Ignored env GJS_DEBUG_OUTPUT
debug3: Ignored env QT4_IM_MODULE
debug3: Ignored env DBUS_SESSION_BUS_ADDRESS
debug3: Ignored env PWD
debug3: Ignored env GTK_MODULES
debug3: Ignored env XDG_CONFIG_DIRS
debug3: Ignored env WINDOWPATH
debug3: Ignored env _
debug3: Ignored env JOURNAL_STREAM
debug3: Ignored env GTK_IM_MODULE
debug3: Ignored env GNOME_DESKTOP_SESSION_ID
debug3: Ignored env MANAGERPID
debug3: Ignored env CLUTTER_IM_MODULE
debug3: Ignored env XDG_SESSION_DESKTOP
debug3: Ignored env LOGNAME
debug3: Ignored env GNOME_TERMINAL_SERVICE
debug3: Ignored env VTE_VERSION
debug3: Ignored env GNOME_SHELL_SESSION_MODE
debug3: Ignored env PATH
debug3: Ignored env XMODIFIERS
debug3: Ignored env SHELL
debug3: Ignored env XDG_RUNTIME_DIR
debug3: Ignored env XDG_SESSION_TYPE
debug3: Ignored env QT_ACCESSIBILITY
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env USERNAME
debug3: Ignored env INVOCATION_ID
debug3: Ignored env SHLVL
debug3: Ignored env XAUTHORITY
debug3: Ignored env IM_CONFIG_CHECK_ENV
debug3: Ignored env DISPLAY
debug3: Ignored env TERM
debug3: Ignored env GDMSESSION
debug3: Ignored env IM_CONFIG_PHASE
debug3: Ignored env OLDPWD
debug3: Ignored env ZSH
debug3: Ignored env PAGER
debug3: Ignored env LESS
debug3: Ignored env LSCOLORS
debug3: Ignored env LS_COLORS
debug2: channel 0: request shell confirm 1
debug3: send packet: type 98
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0回答 1
Server Fault用户
回答已采纳
发布于 2020-02-23 21:01:19
您正在寻找ForwardAgent指令在/etc/ssh/ssh_config或~/.ssh/config中：
ForwardAgent指定是否将与身份验证代理的连接(如果有的话)转发到远程计算机。参数必须是“是”或“否”(默认值)。应谨慎地启用代理转发。能够绕过远程主机上的文件权限(对于代理的Unix域套接字)的用户可以通过转发的连接访问本地代理。攻击者无法从代理获取密钥材料，但是他们可以对密钥执行操作，使它们能够使用加载到代理中的标识进行身份验证。
一旦在客户端上启用了它，就可以通过以下方法检查转发的正确功能：
ssh-add -L并验证它是否包含pam_ssh_agent_auth所需的密钥。
编辑：虽然上面的配置选项(或者您在注释中提到的-A命令行选项)几乎肯定会在服务器上打开一个Unix，该套接字将本地ssh代理转发(当然，使用-v选项运行ssh并检查debug1: Requesting authentication agent forwarding.周围的行是否有错误)，但您的shell初始化脚本或另一个系统组件可能会用它自己的(空)代理替换转发的代理。
要进一步调试这个问题，请在服务器上登录后检查SSH_AUTH_SOCK变量：
printenv SSH_AUTH_SOCK转发代理套接字有一个表单/tmp/ssh-XXXXXXXX/agent.的路径，其中XXXXXXXX是一些随机符号，是外壳的父进程id ( $PPID在bash中的值)。即使有什么东西覆盖了这个变量，您仍然可以使用以下方法找到路径：
ls /tmp/ssh-*/agent.$PPID并恢复：
export SSH_AUTH_SOCK=/tmp/ssh-*/agent.$PPID这将留下一个问题，即谁正在覆盖您的SSH_AUTH_SOCK变量。如果我不得不猜测，我会在bash init文件中搜索(在Debian 10 /etc/profile、/etc/profile.d/*.sh、~/.bash_profile、~/.bash_login、~/.profile、/etc/bash.bashrc和~/.bashrc上)，或者systemd启动ssh-agent.service：
systemctl --user status ssh-agent.service页面原文内容由Server Fault提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://serverfault.com/questions/1004196
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