無密碼 SSH 僅適用於調試模式

Question

我有兩台機器，用戶相同，需要在它們之間進行無密碼 ssh，我有兩個用戶 medya 和 orainst

medya home 是 /home/medya/ orainst home 是 /tools/appsw/oracle/orainst

我已經為他們兩個設置了無密碼（是的，我發誓我做了所有的權限，虔誠的）。

它適用於普通主目錄 (medya) 中的任何用戶，但不適用於 orainst。

最奇怪的是，如果我在調試模式下運行 ssh 服務器，它對兩個用戶都非常有效！！！

這是 ssh 作為服務啟動和 ssh 作為調試啟動的日志

這是失敗的地方：

debug1: trying public key file /tools/appsw/oracle/orainst/.ssh/authorized_keys
debug1: Could not open authorized keys '/tools/appsw/oracle/orainst/.ssh/authorized_keys': Permission denied
debug1: restore_uid: 0/0
debug1: temporarily_use_uid: 500/500 (e=0/0)
debug1: trying public key file /tools/appsw/oracle/orainst/.ssh/authorized_keys

這是完整的日志：

[root@ip-10-16-4-114 oracle]# service sshd start

Starting sshd: debug1: sshd version OpenSSH_5.3p1
debug1: read PEM private key done: type RSA
debug1: private host key: #0 type 1 RSA
debug1: read PEM private key done: type DSA
debug1: private host key: #1 type 2 DSA
debug1: rexec_argv[0]='/usr/sbin/sshd'
debug1: rexec_argv[1]='-d'
Set /proc/self/oom_score_adj from 0 to -1000
debug1: Bind to port 22 on 0.0.0.0.
Server listening on 0.0.0.0 port 22.
debug1: Bind to port 22 on ::.
Server listening on :: port 22.
debug1: Server will not fork when running in debugging mode.
debug1: rexec start in 5 out 5 newsock 5 pipe -1 sock 8
debug1: inetd sockets after dupping: 3, 3
Connection from 10.16.4.113 port 56175
debug1: Client protocol version 2.0; client software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3
debug1: permanently_set_uid: 74/74
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: KEX done
debug1: userauth-request for user orainst service ssh-connection method none
debug1: attempt 0 failures 0
debug1: PAM: initializing for "orainst"
debug1: PAM: setting PAM_RHOST to "10.16.4.113"
debug1: PAM: setting PAM_TTY to "ssh"
debug1: userauth-request for user orainst service ssh-connection method publickey
debug1: attempt 1 failures 0
debug1: temporarily_use_uid: 500/500 (e=0/0)
**debug1: trying public key file /tools/appsw/oracle/orainst/.ssh/authorized_keys
debug1: Could not open authorized keys '/tools/appsw/oracle/orainst/.ssh/authorized_keys': Permission denied
debug1: restore_uid: 0/0
debug1: temporarily_use_uid: 500/500 (e=0/0)
debug1: trying public key file /tools/appsw/oracle/orainst/.ssh/authorized_keys**
debug1: Could not open authorized keys '/tools/appsw/oracle/orainst/.ssh/authorized_keys': Permission denied
debug1: restore_uid: 0/0
Failed publickey for orainst from 10.16.4.113 port 56175 ssh2
Connection closed by 10.16.4.113
debug1: do_cleanup
debug1: do_cleanup
debug1: PAM: cleanup

並登錄以調試模式運行 ssh 服務器（當我這樣做時，兩個用戶都可以執行無密碼 ssh）

[root@ip-10-16-4-114 oracle]# /usr/sbin/sshd -d -p 2222
debug1: sshd version OpenSSH_5.3p1
debug1: read PEM private key done: type RSA
debug1: private host key: #0 type 1 RSA
debug1: read PEM private key done: type DSA
debug1: private host key: #1 type 2 DSA
debug1: rexec_argv[0]='/usr/sbin/sshd'
debug1: rexec_argv[1]='-d'
debug1: rexec_argv[2]='-p'
debug1: rexec_argv[3]='2222'
Set /proc/self/oom_score_adj from 0 to -1000
debug1: Bind to port 2222 on 0.0.0.0.
Server listening on 0.0.0.0 port 2222.
debug1: Bind to port 2222 on ::.
Server listening on :: port 2222.
debug1: Server will not fork when running in debugging mode.
debug1: rexec start in 5 out 5 newsock 5 pipe -1 sock 8
debug1: inetd sockets after dupping: 3, 3
Connection from 10.16.4.113 port 47631
debug1: Client protocol version 2.0; client software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3
debug1: permanently_set_uid: 74/74
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: KEX done
debug1: userauth-request for user orainst service ssh-connection method none
debug1: attempt 0 failures 0
debug1: PAM: initializing for "orainst"
debug1: PAM: setting PAM_RHOST to "10.16.4.113"
debug1: PAM: setting PAM_TTY to "ssh"
debug1: userauth-request for user orainst service ssh-connection method publickey
debug1: attempt 1 failures 0
debug1: temporarily_use_uid: 500/500 (e=0/0)
debug1: trying public key file /tools/appsw/oracle/orainst/.ssh/authorized_keys
debug1: fd 4 clearing O_NONBLOCK
debug1: matching key found: file /tools/appsw/oracle/orainst/.ssh/authorized_keys, line 1
Found matching RSA key: 6c:ab:f3:3b:68:c3:ed:f1:d6:ae:a5:f8:06:2f:d3:8c
debug1: restore_uid: 0/0
debug1: ssh_rsa_verify: signature correct
debug1: do_pam_account: called
Accepted publickey for orainst from 10.16.4.113 port 47631 ssh2
debug1: monitor_child_preauth: orainst has been authenticated by privileged process
debug1: temporarily_use_uid: 500/500 (e=0/0)
debug1: ssh_gssapi_storecreds: Not a GSSAPI mechanism
debug1: restore_uid: 0/0
debug1: SELinux support enabled
debug1: PAM: establishing credentials
debug1: temporarily_use_uid: 500/500 (e=0/0)
debug1: ssh_gssapi_storecreds: Not a GSSAPI mechanism
debug1: restore_uid: 0/0
User child is on pid 6171
debug1: PAM: establishing credentials
debug1: permanently_set_uid: 500/500
debug1: Entering interactive session for SSH2.
debug1: server_init_dispatch_20
debug1: server_input_channel_open: ctype session rchan 0 win 1048576 max 16384
debug1: input_session_request
debug1: channel 0: new [server-session]
debug1: session_new: session 0
debug1: session_open: channel 0
debug1: session_open: session 0: link with channel 0
debug1: server_input_channel_open: confirm session
debug1: server_input_global_request: rtype no-more-sessions@openssh.com want_reply 0
debug1: server_input_channel_req: channel 0 request pty-req reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req pty-req
debug1: Allocating pty.
debug1: session_new: session 0
debug1: session_pty_req: session 0 alloc /dev/pts/1
debug1: server_input_channel_req: channel 0 request env reply 0
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req env
debug1: server_input_channel_req: channel 0 request shell reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req shell

Answer 1

我相信真正的問題是 .ssh 文件夾路徑中存在符號鏈接會觸發權限檢查。 類似於 SELinux 要求authorized_keys 文件禁止對文件進行組寫訪問（本質上chmod 值為600），它對.ssh 文件夾和authorized_keys 文件路徑中的任何符號鏈接強制執行相同的規則。

我認為這里的答案很好： https : //unix.stackexchange.com/questions/152417/why-cant-i-use-public-private-key-authentication-with-ssh-on-arch-linux

Answer 2

我也遇到了這個問題，並使用以下方法修復了它：

restorecon .ssh/
restorecon .ssh/authorized_keys

這里的其他答案讓我知道這是一個 SELinux 問題，將默認上下文恢復到文件夾及其內容解決了這個問題。

Answer 3

我用這個解決了這個問題

echo 0 > /selinux/enforce

結果 selinux 不喜歡我的用戶的主文件夾是一個符號鏈接。

Answer 4

同樣的事情發生在我身上，但我在 Windows 中運行 OpenSSH。 由於此線程中的答案，我意識到原因可能是對 authorized_keys 文件的權限。 登錄在調試模式下工作，因為該模式由對文件具有權限的同一用戶運行，但 OpenSSH 服務以 LocalSystem 用戶運行。 授予該用戶對authorized_keys 的權限解決了這個問題。