Linux

如何使用 RSA 密鑰設置無密碼 ssh

  • February 26, 2016

我正在嘗試在兩台機器之間設置無密碼 SSH 配置，但遇到了問題。那裡有很多我遵循的方法，但都沒有成功。這是我採取的步驟

  1. 在客戶端上生成身份驗證密鑰。（當提示輸入密碼時按輸入鍵） [root@box1:.ssh/$] ssh-keygen -t rsa
  2. 將公鑰複製到伺服器。 [root@box1:.ssh/$] scp id_rsa.pub root@box2:.ssh/authorized_keys
  3. 驗證已在伺服器上成功創建授權密鑰
  4. 執行了以下命令： [root@box1:.ssh/$] ssh root@box2 ls

我仍然被提示輸入密碼。我閱讀了一篇關於“取決於正在執行的 SSH 版本…”的說明（儘管它沒有指定哪些版本需要這個），它可能需要：

  • .ssh/authorized_keys2 中的公鑰
  • .ssh 到 700 的權限
  • .ssh/authorized_keys2 的權限為 640

我也遵循了這些步驟，但沒有成功。我已驗證 home、root 和 .ssh 目錄不可按組寫入（根據https://unix.stackexchange.com/tags/ssh/info）。

有人知道我缺少什麼嗎？

謝謝

編輯：我還使用 ssh-copy-id 命令將公鑰複製到第二個框並生成.ssh/authorized_keys文件。

[root@box1:.ssh/$] ssh-copy-id -i id_rsa.pub root@box2

EDIT2：包括版本資訊

// box1（生成系統密鑰）

  • Linux 2.6.34
  • OpenSSH_5.5p1 Debian-6，OpenSSL 0.9.8o 2010 年 6 月 1 日

// 盒子2

  • Linux 2.6.33
  • Dropbear客戶端 v0.52

EDIT3：調試輸出

[root@box1:.ssh/$] ssh -vvv root@box2 ls
OpenSSH_5.5p1 Debian-6, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to box2 [box2] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug3: Not a RSA1 key file /root/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /root/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version dropbear_0.52
debug1: no match: dropbear_0.52
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-6
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-    
group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit:
ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-    
cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysatoe
debug2: kex_parse_kexinit:
aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-    
cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysatoe
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-    
sha1-96,hmac-md5-96
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-
sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,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: diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-ctr,3des-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes256-cbc,twofish256-cbc,twofish-
cbc,twofish128-cbc,blowfish-cbc
debug2: kex_parse_kexinit:
aes128-ctr,3des-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes256-cbc,twofish256-cbc,twofish-
cbc,twofish128-cbc,blowfish-cbc
debug2: kex_parse_kexinit: hmac-sha1-96,hmac-sha1,hmac-md5
debug2: kex_parse_kexinit: hmac-sha1-96,hmac-sha1,hmac-md5
debug2: kex_parse_kexinit: zlib,zlib@openssh.com,none
debug2: kex_parse_kexinit: zlib,zlib@openssh.com,none
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr hmac-md5 none
debug2: dh_gen_key: priv key bits set: 132/256
debug2: bits set: 515/1024
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
debug3: check_host_in_hostfile: host 192.168.20.10 filename
/root/.ssh/known_hosts
debug3: check_host_in_hostfile: host 192.168.20.10 filename
/root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 3
debug1: Host 'box2' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:3
debug2: bits set: 522/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
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: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /root/.ssh/id_rsa (0x54b1c340)
debug2: key: /root/.ssh/id_dsa ((nil))
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred
gssapi-keyex,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: /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /root/.ssh/id_dsa
debug3: no such identity: /root/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password

EDIT4：另一個有趣的發展。我沒有在box1（執行OpenSSH）上生成密鑰並將它們複製到box2（執行dropbear），而是反向執行：

[root@box2:.ssh/$] dropbearkey -t rsa -f id_rsa [root@box2:.ssh/$] dropbearkey -y -f id_rsa | grep "^ssh-rsa" >> authorized_keys [root@box2:.ssh/$] scp authorized_keys root@box1:.ssh/

只有當我指定 ID 文件時，我才能成功地從 box2 到 box1 發出無密碼命令： [root@box2:.ssh/$] ssh -i id_rsa root@box1 ls

仍然無法從 box1 (OpenSSH) 向 box2 (dropbear) 發出命令。

我找到了問題的根源。/var/log/messages關於奇怪的所有權，有一條模糊的資訊告訴了我。/root所以我檢查了，/root/.ssh和的權限/root/.ssh/*都是正確的（700），但所有權是default.default。我不確定那是怎麼發生的……但我跑了：

[root@box1:.ssh/$] chown root.root /root
[root@box1:.ssh/$] chown root.root /root/.ssh
[root@box1:.ssh/$] chown root.root /root/.ssh/*

將所有權更改為 root 和無密碼登錄可以雙向工作。

引用自：https://unix.stackexchange.com/questions/47723

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