scp requisitos para o modo em lote

Question

Estou lançando um script de um servidor Jenkins (no RHEL6) que, entre outras coisas, usa SCP com "BatchMode yes" para copiar um arquivo de uma máquina remota. O script é executado corretamente fora do Jenkins, mas falha dentro dele. O log detalhado do SCP mostra:

debug1: Next authentication method: publickey
debug1: Offering public key: /var/lib/jenkins/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: Trying private key: /var/lib/jenkins/.ssh/id_dsa

Portanto, há algo faltando no usuário do Jenkins que é necessário para efetuar login. Não é uma entrada known_hosts, ou pelo menos o host correto está listado em /var/lib/jenkins/.ssh/known_hosts. O que mais poderia ser?

Editar : por solicitação, o comando era

scp -vvv -o "BatchMode yes" [email protected]:myfile.txt .

Aqui está um snippet de log mais extenso:

Executing: program /usr/bin/ssh host myserver.com, user myuser, command scp -v -f myfile.txt
OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to myserver.com [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug1: identity file /var/lib/jenkins/.ssh/identity type -1
debug1: identity file /var/lib/jenkins/.ssh/identity-cert type -1
debug1: identity file /var/lib/jenkins/.ssh/id_rsa type 1
debug1: identity file /var/lib/jenkins/.ssh/id_rsa-cert type -1
debug1: identity file /var/lib/jenkins/.ssh/id_dsa type -1
debug1: identity file /var/lib/jenkins/.ssh/id_dsa-cert type -1
debug1: identity file /var/lib/jenkins/.ssh/id_ecdsa type -1
debug1: identity file /var/lib/jenkins/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.2
debug1: match: OpenSSH_6.2 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug3: Wrote 960 bytes for a total of 981
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],[email protected],[email protected],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,[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-sha2-512,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-512,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: [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]
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
debug3: Wrote 24 bytes for a total of 1005
debug2: dh_gen_key: priv key bits set: 131/256
debug2: bits set: 773/1536
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: Wrote 208 bytes for a total of 1213
debug3: check_host_in_hostfile: host myserver.com filename /var/lib/jenkins/.ssh/known_hosts
debug3: check_host_in_hostfile: host myserver.com filename /var/lib/jenkins/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug3: check_host_in_hostfile: host xxx.xxx.xxx.xxx filename /var/lib/jenkins/.ssh/known_hosts
debug3: check_host_in_hostfile: host xxx.xxx.xxx.xxx filename /var/lib/jenkins/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 3
debug1: Host 'myserver.com' is known and matches the RSA host key.
debug1: Found key in /var/lib/jenkins/.ssh/known_hosts:2
debug2: bits set: 759/1536
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
debug3: Wrote 16 bytes for a total of 1229
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug3: Wrote 48 bytes for a total of 1277
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /var/lib/jenkins/.ssh/identity ((nil))
debug2: key: /var/lib/jenkins/.ssh/id_rsa (0x7f38a83ee310)
debug2: key: /var/lib/jenkins/.ssh/id_dsa ((nil))
debug2: key: /var/lib/jenkins/.ssh/id_ecdsa ((nil))
debug3: Wrote 64 bytes for a total of 1341
debug1: Authentications that can continue: publickey,keyboard-interactive
debug3: start over, passed a different list publickey,keyboard-interactive
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey
debug3: authmethod_lookup publickey
debug3: remaining preferred: ,gssapi-with-mic,publickey
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /var/lib/jenkins/.ssh/identity
debug3: no such identity: /var/lib/jenkins/.ssh/identity
debug1: Offering public key: /var/lib/jenkins/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug3: Wrote 368 bytes for a total of 1709
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug2: input_userauth_pk_ok: SHA1 fp 72:a5:45:d3:f2:6d:15:c4:2e:f9:37:34:44:10:2b:b9:59:ee:18:c0
debug3: sign_and_send_pubkey: RSA 72:a5:45:d3:f2:6d:15:c4:2e:f9:37:34:44:10:2b:b9:59:ee:18:c0
debug1: Trying private key: /var/lib/jenkins/.ssh/id_dsa
debug3: no such identity: /var/lib/jenkins/.ssh/id_dsa
debug1: Trying private key: /var/lib/jenkins/.ssh/id_ecdsa
debug3: no such identity: /var/lib/jenkins/.ssh/id_ecdsa
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey,keyboard-interactive).

    

Answer 1

Depois de um tempo, percebi que tinha criado as chaves sozinho, com apenas "sudo ssh-keygen". Isso significava que a chave realmente pertencia ao usuário root e o usuário não tinha permissão para lê-lo. Se ssh tivesse me dito isso, não há problema. Aparentemente, porém, a primeira coisa que o ssh faz se não puder ler a chave é pedir uma frase-senha. Mas, como estava em execução no modo em lote, não foi possível solicitar uma frase secreta, por isso desistiu e falhou a chave. Depois que eu coloquei os arquivos-chave para o usuário Jenkins, tudo funcionou.

    

Answer 2

Aqui está o bit no log que informa o que está acontecendo:

debug1: Trying private key: /var/lib/jenkins/.ssh/identity
debug3: no such identity: /var/lib/jenkins/.ssh/identity
debug1: Offering public key: /var/lib/jenkins/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug3: Wrote 368 bytes for a total of 1709
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug2: input_userauth_pk_ok: SHA1 fp 72:a5:45:d3:f2:6d:15:c4:2e:f9:37:34:44:10:2b:b9:59:ee:18:c0
debug3: sign_and_send_pubkey: RSA 72:a5:45:d3:f2:6d:15:c4:2e:f9:37:34:44:10:2b:b9:59:ee:18:c0
debug1: Trying private key: /var/lib/jenkins/.ssh/id_dsa
debug3: no such identity: /var/lib/jenkins/.ssh/id_dsa
debug1: Trying private key: /var/lib/jenkins/.ssh/id_ecdsa
debug3: no such identity: /var/lib/jenkins/.ssh/id_ecdsa
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey,keyboard-interactive).

Eu vejo algumas coisas ruins acontecendo aqui.

Primeiro, ele oferece até /var/lib/jenkins/.ssh/id_rsa como chave pública, quando deveria ser uma chave privada. Pode ser esclarecedor dar uma olhada no arquivo de configuração do sshd.

Em seguida, ele procura por chaves particulares e não consegue encontrá-las em nenhum desses lugares:

/var/lib/jenkins/.ssh/id_dsa
/var/lib/jenkins/.ssh/id_ecdsa

O que é estranho porque anteriormente no arquivo de log, ele alegava que esses arquivos existiam:

debug1: identity file /var/lib/jenkins/.ssh/identity type -1
debug1: identity file /var/lib/jenkins/.ssh/identity-cert type -1
debug1: identity file /var/lib/jenkins/.ssh/id_rsa type 1
debug1: identity file /var/lib/jenkins/.ssh/id_rsa-cert type -1
debug1: identity file /var/lib/jenkins/.ssh/id_dsa type -1
debug1: identity file /var/lib/jenkins/.ssh/id_dsa-cert type -1
debug1: identity file /var/lib/jenkins/.ssh/id_ecdsa type -1
debug1: identity file /var/lib/jenkins/.ssh/id_ecdsa-cert type -1

Aqui estão as coisas que eu tentaria:

• chmod go-rwx /var/lib/jenkins/.ssh/*
  Isso garantirá que somente o usuário tenha permissões de leitura para os arquivos de chave. Isso é importante, pois o OpenSSH, se configurado para ser seguro, se recusará a trabalhar com arquivos-chave publicamente legíveis.
• O arquivo de chaves foi criado com uma senha? Os arquivos de chave protegidos por senha não funcionarão para automação, portanto, certifique-se de que os arquivos de chave não sejam protegidos por senha.
• O arquivo-chave está instalado no myserver.com em /home/myuser/.ssh/authorized_keys e você executou chmod go-rwx /home/myuser/.ssh/* no myserver.com?