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问题[sshd](computer)

Martin Hope
BoZenKhaa
Asked: 2020-11-24 02:49:23 +0800 CST
  • 7

我无法理解文件PermitTunnel中的选项sshd_config。此选项与AllowTcpForwarding? 拥有PermitTunnel no似乎对连接到服务器的隧道没有任何影响。

男人这样说PermitTunnel：

 Specifies whether tun(4) device forwarding is allowed.  The argument must be yes,
             point-to-point (layer 3), ethernet (layer 2), or no.  Specifying yes permits both
             point-to-point and ethernet.  The default is no.

             Independent of this setting, the permissions of the selected tun(4) device must allow access
             to the user.

但这对我来说意义不大。

debian sshd
Martin Hope
Ross Rogers
Asked: 2020-06-25 12:23:26 +0800 CST
  • 6

我正在创建从客户端到服务器的隧道，例如：

ssh -N \
  -o ConnectTimeout=9 \
  -o ServerAliveInterval=5 \
  -o ServerAliveCountMax=1 \
  -o ExitOnForwardFailure=yes \
  -R 0.0.0.0:10021:localhost:22  \
  [email protected]

如果我拔下客户端以太网，它会超时：

Timeout, server example.com not responding.

如果我立即尝试重新连接，它会说：

Error: remote port forwarding failed for listen port 10021

这是因为服务器仍然显示：

sudo netstat -tnlpa | grep 10021
tcp        0      0 0.0.0.0:10021           0.0.0.0:*               LISTEN      30173/sshd: foo

sshd客户端连接消失后，如何让服务器关闭端口？

ssh sshd
Martin Hope
HappyDog
Asked: 2020-05-03 00:42:53 +0800 CST
  • 7

我正在尝试以非 root 用户身份运行 SSH 守护程序，因为我想在我没有 root 访问权限的服务器上提供对我们 Git 存储库的 SSH 访问权限。我已经使用自定义配置和本地证书运行它，但登录当前无法正常工作。

我正在使用以下版本sshd：

OpenSSH_7.4p1，OpenSSL 1.0.2k-fips 2017 年 1 月 26 日

在这个阶段，我不寻求有关配置等方面的帮助（如有必要，我将发布单独的问题）。在我投入更多时间之前，我只想知道是否存在硬编码限制，这意味着这是不可能的。

SSH 守护程序中是否有任何硬限制阻止它作为非 root 用户成功使用？

linux sshd
Martin Hope
0laf
Asked: 2020-04-26 15:10:59 +0800 CST
  • 6

我想配置 sshd 以便接受同一专用网络内的任何用户，但拒绝其他所有人。

示例：我的 IP 地址是 192.168.1.159，所以应该允许网络 192.168.1.0 内的任何人。

背景：

目前我正在配置一个嵌入式设备映像，并考虑将其添加为一个小的附加安全措施。该映像将在不同位置的设备上运行。IP 地址将通过 DHCP 分配，每个系统可能连接到不同配置的专用网络（如 10.0.1.0、192.168.100.0、...）。

所以我想，理想情况下，我想要的是：

DenyUsers *
Match Address OWN_DEVICE_ADDRESS/24
    AllowUsers *

然而，阅读手册页sshd_config我找不到这种可能性。

所以我最终想到了接受所有具有专用网络 ip v4 地址的用户，并将以下内容附加到/etc/ssh/sshd_config：

Match Address 192.168.0.0/16,172.16.0.0/12,10.0.0.0/8
        AllowUsers *

DenyUsers *

然而，测试这个（通过输出systemctl status sshd）表明，即使我在同一个网络中，该DenyUsers规则仍然是最重要的：

Apr 25 23:37:43 host sshd[27733]: User test from 192.168.1.166 not allowed because listed in DenyUsers *

所以我想我没能理解DenyUsers. 你们能帮帮我吗？

openssh sshd
Martin Hope
Martin James
Asked: 2019-04-12 06:59:42 +0800 CST
  • 2

sshd 遇到一个奇怪的问题，它将接受一个密钥，但前提是它不是名称“id_rsa”

[root@login01 .ssh]# cp id_rsa idrsa 
[root@login01 .ssh]# md5sum id_rsa idrsa
e45bc86220892d9212819704cdf116fb  id_rsa
e45bc86220892d9212819704cdf116fb  idrsa
[root@login01 .ssh]# ssh -i id_rsa mgmt01
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
[root@login01 .ssh]# ssh -i idrsa mgmt01
Last login: Wed Apr 10 16:46:49 2019 from login01-ib
[root@mgmt01 ~]#

以前有人遇到过这个问题吗？我检查了所有权限，它们看起来很好。在这个问题上挠我的头。

对于冗长：

我们得到的坏钥匙

[root@login01 .ssh]# ssh -i id_rsa mgmt01 -vvv
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 58: Applying options for *
debug2: resolving "mgmt01" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to mgmt01 [10.1.1.252] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file id_rsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to mgmt01:22 as 'root'
debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /root/.ssh/known_hosts:5
debug3: load_hostkeys: loaded 1 keys from mgmt01
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],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,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],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,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
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: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: curve25519-sha256 need=64 dh_need=64
debug1: kex: curve25519-sha256 need=64 dh_need=64
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:iN76ArdjVn/wZlIOL66artv0q+xOcTInSyG+29JKd7w
debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /root/.ssh/known_hosts:5
debug3: load_hostkeys: loaded 1 keys from mgmt01
debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /root/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from 10.1.1.252
debug1: Host 'mgmt01' is known and matches the ECDSA host key.
debug1: Found key in /root/.ssh/known_hosts:5
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey 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 after 134217728 blocks
debug2: key: id_rsa (0x560301c1b190), explicit
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
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,gssapi-keyex,gssapi-with-mic
debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-keyex
debug3: remaining preferred: gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-keyex
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug2: we did not send a packet, disable method
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure.  Minor code may provide more information
No Kerberos credentials available (default cache: KEYRING:persistent:0)
debug1: Unspecified GSS failure.  Minor code may provide more information
No Kerberos credentials available (default cache: KEYRING:persistent:0)
debug2: we did not send a packet, disable method
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: id_rsa
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

我们得到的好钥匙：

debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: idrsa
debug3: sign_and_send_pubkey: RSA SHA256:dnizM1DopxxMTYUZzfQFx+ZKSuESOuT1ob1xaJicQI0
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to mgmt01 ([10.1.1.252]:22).
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 [email protected]
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug3: receive packet: type 91
debug2: callback start
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 XDG_SESSION_ID
debug3: Ignored env HOSTNAME
debug3: Ignored env TERM
debug3: Ignored env SHELL
debug3: Ignored env HISTSIZE
debug3: Ignored env SSH_CLIENT
debug3: Ignored env PERL5LIB
debug3: Ignored env QTDIR
debug3: Ignored env QTINC
debug3: Ignored env PERL_MB_OPT
debug3: Ignored env SSH_TTY
debug3: Ignored env QT_GRAPHICSSYSTEM_CHECKED
debug3: Ignored env USER
debug3: Ignored env LS_COLORS
debug3: Ignored env MAIL
debug3: Ignored env PATH
debug3: Ignored env PWD
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env MODULEPATH
debug3: Ignored env LOADEDMODULES
debug3: Ignored env KDEDIRS
debug3: Ignored env HISTCONTROL
debug3: Ignored env SHLVL
debug3: Ignored env HOME
debug3: Ignored env PERL_LOCAL_LIB_ROOT
debug3: Ignored env LOGNAME
debug3: Ignored env QTLIB
debug3: Ignored env CVS_RSH
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env SSH_CONNECTION
debug3: Ignored env MODULESHOME
debug3: Ignored env LESSOPEN
debug3: Ignored env XDG_RUNTIME_DIR
debug3: Ignored env QT_PLUGIN_PATH
debug3: Ignored env PERL_MM_OPT
debug3: Ignored env BASH_FUNC_module()
debug3: Ignored env _
debug3: Ignored env OLDPWD
debug2: channel 0: request shell confirm 1
debug3: send packet: type 98
debug2: 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

对于证书，我在 config 和 /etc/ssh 中看不到以下内容；

HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
AuthorizedKeysFile  .ssh/authorized_keys

[root@mgmt01 ssh]# ll
total 608
-rw-r--r--. 1 root root     581843 Apr 10  2018 moduli
-rw-r--r--. 1 root root       2304 Apr 10 16:19 ssh_config
-rw-------. 1 root root       4431 Apr 10 16:24 sshd_config
-rw-r-----  1 root ssh_keys    227 Mar 29 12:41 ssh_host_ecdsa_key
-rw-r--r--  1 root root        162 Mar 29 12:41 ssh_host_ecdsa_key.pub
-rw-r-----  1 root ssh_keys    387 Mar 29 12:41 ssh_host_ed25519_key
-rw-r--r--  1 root root         82 Mar 29 12:41 ssh_host_ed25519_key.pub
-rw-r-----  1 root ssh_keys   1675 Mar 29 12:41 ssh_host_rsa_key
-rw-r--r--  1 root root        382 Mar 29 12:41 ssh_host_rsa_key.pub

我不确定后者是否与您的问题特别相关。

linux sshd
Martin Hope
Boyan Atanasov
Asked: 2019-04-06 03:41:48 +0800 CST
  • 1

如果我 ssh 到服务器并且我打开顶部数据包正在通过网络发送，那么正常的 ssh 超时（因为空闲）将不起作用。
这意味着如果用户正在运行顶级进程，则 ssh 连接可以永远保持打开状态。

有没有办法在一定时间后强制 ssh 超时（或断开连接），以避免仅仅因为顶部打开就永远保持连接？

更新： 场景是人们在服务器打开顶部的 ssh 并且只要他们不关闭自己的顶部 ssh 将永远保持打开状态，这意味着它可以多次完成并且当我登录到服务器并执行“w " 命令（显示谁登录了）有许多 ssh 会话打开超过几周

ssh linux sshd