我收到通知，在运行 Ubuntu 的 Amazon EC2 服务器上，SFTP 访问不再有效。我已为该服务器上的其他用户创建了一些 SFTP 访问权限。受限用户访问权限仍然有效。但是，我们拥有 .pem 密钥文件的“ubuntu”用户的根 SFTP 访问权限不再有效。
我从调试输出中获取了退出状态 126。FireFTP 报告：
Connected (version 2.0, client OpenSSH_5.9p1NaNDebian-5ubuntu1.3)
Authentication (publickey) successful!
Secsh channel 1 opened.
Error message= uncaught exception: EOFError: "undefined"
URL=
Line Number= 0
我设法通过在 /etc/ssh/sshd_config 中添加以下内容来允许 SFTP 访问：
Match user ubuntu
ForceCommand internal-sftp
但是这会禁用 SSH 访问！！
我还确保在 sshd_config 中设置了“PermitRootLogin yes”。
我也尝试让 ubuntu 主文件夹归 root:root 所有，但似乎没有什么区别。
我不确定我可能无意中更改了什么导致了这个错误。
提前致谢
auth.log条目：
> Jun 24 10:21:26 ip-**** sshd[24096]: Accepted publickey for
> ubuntu from **** port 63696 ssh2 Jun 24 10:21:26
> ip-**** sshd[24096]: pam_unix(sshd:session): session opened
> for user ubuntu by (uid=0) Jun 24 10:21:26 ip-****
> sshd[24182]: subsystem request for sftp by user ubuntu Jun 24 10:21:27
> ip-**** sshd[24182]: Received disconnect from ****:
> 11: disconnected by user Jun 24 10:21:27 ip-172-31-30-50 sshd[24096]:
> pam_unix(sshd:session): session closed for user ubuntu
SFTP 调试输出如下：
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug1: Reading configuration data /Users/<user>/.ssh/config
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: /etc/ssh_config line 102: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to ****** port 22.
debug1: Connection established.
debug1: identity file ****.pem type -1
debug1: identity file ****.pem-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian-5ubuntu1.3
debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1.3 pat OpenSSH_5*
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: [email protected],[email protected],ssh-rsa,[email protected],[email protected],ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,[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],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],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: 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
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,[email protected]
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,[email protected]
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,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
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
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 128/256
debug2: bits set: 513/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA ****
debug1: Host '****' is known and matches the RSA host key.
debug1: Found key in /Users/adamelemental/.ssh/known_hosts:36
debug2: bits set: 505/1024
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: /Users/adamelemental/work/e247-admin/aws/e247-main-eu.pem (0x0), explicit
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: ****.pem
debug1: read PEM private key done: type RSA
debug2: we sent a publickey packet, wait for reply
debug1: Authentication succeeded (publickey).
Authenticated to **** ([****]:22).
debug2: fd 4 setting O_NONBLOCK
debug1: channel 0: new [client-session]
debug2: channel 0: send open
debug1: Requesting [email protected]
debug1: Entering interactive session.
debug2: callback start
debug2: fd 3 setting TCP_NODELAY
debug2: client_session2_setup: id 0
debug1: Sending environment.
debug1: Sending env LANG = en_GB.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending subsystem: sftp
debug2: channel 0: request subsystem confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 2097152
debug2: channel_input_status_confirm: type 99 id 0
debug2: subsystem request accepted on channel 0
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: client_input_channel_req: channel 0 rtype [email protected] reply 0
debug2: channel 0: rcvd eow
debug2: channel 0: close_read
debug2: channel 0: input open -> closed
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug2: channel 0: rcvd close
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug2: channel 0: gc: user detached
debug2: channel 0: send close
debug2: channel 0: is dead
debug2: channel 0: garbage collecting
debug1: channel 0: free: client-session, nchannels 1
debug1: fd 0 clearing O_NONBLOCK
Transferred: sent 2768, received 2160 bytes, in 0.4 seconds
Bytes per second: sent 7600.3, received 5930.8
debug1: Exit status 126
Connection closed
答案1
退出代码 126 是bash已找到但无法执行的命令的错误代码。请参阅这里和这里。 例如：
$ /dev/null
-bash: /dev/null: Permission denied
$ echo $?
126
当您不强制internal-sftp,使用 OpenSSH 服务器时，它会使用名为 的程序sftp-server来处理远程 SFTP 会话。我猜想是sftp-server此系统上的程序已被标记为不可执行，或者 SSHD 配置不正确。
该sshd_config文件应该有一个subsystem类似于以下内容的 SFTP 行（注意，我不知道该文件在 Ubuntu 上的具体位置）：
Subsystem sftp /path/to/sftp-server
找到此行，验证它是否引用了程序的有效副本sftp-server，并验证程序本身是否可执行：
-rwxr-xr-x 1 root root 63552 Apr 11 2013 /path/to/sftp-server
^ ^ ^