Impossibile avviare il server sFTP


10

Sto avendo problemi a far funzionare sFTP mentre non ci sono problemi con ssh. Fondamentalmente sto costruendo zlib, openssl e openssh per un processore ARM usando un filesystem Linux incorporato esistente. Dopo aver cercato idee, mi è sembrato un problema comune, ma non ho fatto alcun progresso. Ho solo un utente definito, che è root con una password vuota.

Sto usando openssh versione 4.7p1 e ho modificato sshd_config con le seguenti impostazioni:

PermitRootLogin yes
PermitEmptyPasswords yes
UseDNS yes
UsePrivilegeSeparation no
SyslogFacility AUTH
LogLevel DEBUG3
Subsystem sftp /usr/local/libexec/sftp-server -f AUTH -l DEBUG3

Il server sftp si trova in / usr / local / libexec e ha le seguenti autorizzazioni:

root@arm:/usr/local/libexec# ls -l
-rwxr-xr-x    1 root     root         65533 Oct  3 22:12 sftp-server
-rwx--x--x    1 root     root        233539 Oct  3 22:12 ssh-keysign

So che è stato trovato sftp-server (il percorso è impostato in sshd_config) perché se rinomino l'eseguibile sftp_server, ottengo il seguente errore:

auth.err sshd[1698]: error: subsystem: cannot stat /usr/local/libexec/sftp-server: No such file or directory                                                        
auth.info sshd[1698]: subsystem request for sftp failed, subsystem not found   

Inoltre, gli init-script di login del target sono molto semplici e consistono in un singolo file (etc / profile.d / local.sh), che contiene solo le definizioni per LD_LIBRARY_PATH, PATH e PYTHONPATH come mostrato di seguito:

#!/bin/sh
export LD_LIBRARY_PATH="/usr/local/lib"
export PATH="/usr/local/bin:/usr/local/libexec:${PATH}"
export PYTHONPATH="/home/root/python"

Come puoi vedere .bashrc, .profile, ecc. Non esistono nella home directory di root:

root@arm:~# ls -la                                                                                                                                                                      
drwxr-xr-x    2 root     root          4096 Oct  4 14:57 .                                                                                                                                    
drwxr-xr-x    3 root     root          4096 Oct  4 01:11 ..                                                                                                                                   
-rw-------    1 root     root           120 Oct  4 01:21 .bash_history

Ecco l'output del registro di sistema quando si utilizza FileZilla per connettersi al server sftp sulla destinazione. Dal registro sembra che sia stato trovato l'eseguibile sftp-server, ma i processi figlio sono usciti immediatamente. Sto usando argomenti di debug quando chiamo sftp-server in sshd_config (Sottosistema sftp / usr / local / libexec / sftp-server -f AUTH -l DEBUG3), ma nessun log è stato catturato.

Oct  4 14:29:45 arm auth.info sshd[2070]: Connection from 192.168.1.12 port 45888                                                                                                       
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: Client protocol version 2.0; client software version PuTTY_Local:_Mar_28_2012_12:33:05                                               
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: no match: PuTTY_Local:_Mar_28_2012_12:33:05                                                                                          
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: Enabling compatibility mode for protocol 2.0                                                                                         
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: Local version string SSH-2.0-OpenSSH_4.7                                                                                             
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: fd 3 setting O_NONBLOCK                                                                                                              
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: list_hostkey_types: ssh-rsa,ssh-dss                                                                                                  
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: SSH2_MSG_KEXINIT sent                                                                                                                
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: SSH2_MSG_KEXINIT received                                                                                                            
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellma1
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: ssh-rsa,ssh-dss                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysr
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysr
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96         
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96         
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: none,zlib@openssh.com                                                                                             
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: none,zlib@openssh.com                                                                                             
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit:                                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit:                                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: first_kex_follows 0                                                                                               
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: reserved 0                                                                                                        
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellma1
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: ssh-rsa,ssh-dss                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: aes256-ctr,aes256-cbc,rijndael-cbc@lysator.liu.se,aes192-ctr,aes192-cbc,aes128-ctr,aes128-cbc,blowfish-ctr,blowfi8
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: aes256-ctr,aes256-cbc,rijndael-cbc@lysator.liu.se,aes192-ctr,aes192-cbc,aes128-ctr,aes128-cbc,blowfish-ctr,blowfi8
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: none,zlib                                                                                                         
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: none,zlib                                                                                                         
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit:                                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit:                                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: first_kex_follows 0                                                                                               
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_parse_kexinit: reserved 0                                                                                                        
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: mac_setup: found hmac-sha1                                                                                                           
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: kex: client->server aes256-ctr hmac-sha1 none                                                                                        
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: mac_setup: found hmac-sha1                                                                                                           
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: kex: server->client aes256-ctr hmac-sha1 none                                                                                        
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received                                                                                             
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent                                                                                                       
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: dh_gen_key: priv key bits set: 277/512                                                                                               
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: bits set: 2052/4096                                                                                                                  
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: bits set: 2036/4096                                                                                                                  
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent                                                                                                       
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: kex_derive_keys                                                                                                                      
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: set_newkeys: mode 1                                                                                                                  
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug2: cipher_init: set keylen (16 -> 32)                                                                                                   
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: SSH2_MSG_NEWKEYS sent                                                                                                                
Oct  4 14:29:45 arm auth.debug sshd[2070]: debug1: expecting SSH2_MSG_NEWKEYS                                                                                                           
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: set_newkeys: mode 0                                                                                                                  
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: cipher_init: set keylen (16 -> 32)                                                                                                   
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: SSH2_MSG_NEWKEYS received                                                                                                            
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: KEX done                                                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: userauth-request for user root service ssh-connection method none                                                                    
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: attempt 0 failures 0                                                                                                                 
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug3: Trying to reverse map address 192.168.1.12.                                                                                          
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: parse_server_config: config reprocess config len 302                                                                                 
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: input_userauth_request: setting up authctxt for root                                                                                 
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: input_userauth_request: try method none                                                                                              
Oct  4 14:29:46 arm auth.info sshd[2070]: Accepted none for root from 192.168.1.12 port 45888 ssh2                                                                                      
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: Entering interactive session for SSH2.                                                                                               
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: fd 4 setting O_NONBLOCK                                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: fd 5 setting O_NONBLOCK                                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: server_init_dispatch_20                                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: server_input_channel_open: ctype session rchan 256 win 2147483647 max 16384                                                          
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: input_session_request                                                                                                                
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: channel 0: new [server-session]                                                                                                      
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_new: init                                                                                                                    
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_new: session 0                                                                                                               
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_open: channel 0                                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_open: session 0: link with channel 0                                                                                         
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: server_input_channel_open: confirm session                                                                                           
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: server_input_channel_req: channel 0 request simple@putty.projects.tartarus.org reply 0                                               
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_by_channel: session 0 channel 0                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_input_channel_req: session 0 req simple@putty.projects.tartarus.org                                                          
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: server_input_channel_req: channel 0 request subsystem reply 1                                                                        
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_by_channel: session 0 channel 0                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_input_channel_req: session 0 req subsystem                                                                                   
Oct  4 14:29:46 arm auth.info sshd[2070]: subsystem request for sftp                                                                                                                    
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: subsystem: exec() /usr/local/libexec/sftp-server -f AUTH -l DEBUG3                                                                   
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: fd 3 setting TCP_NODELAY                                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: fd 7 setting O_NONBLOCK                                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug3: fd 7 is O_NONBLOCK                                                                                                                   
Oct  4 14:29:46 arm auth.debug sshd[2073]: debug1: permanently_set_uid: 0/0                                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2073]: debug3: channel 0: close_fds r -1 w -1 e -1 c -1                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: read<=0 rfd 7 len -1                                                                                                      
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: read failed                                                                                                               
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: close_read                                                                                                                
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: input open -> drain                                                                                                       
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: ibuf empty                                                                                                                
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: send eof                                                                                                                  
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: input drain -> closed                                                                                                     
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: notify_done: reading                                                                                                                 
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: Received SIGCHLD.                                                                                                                    
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_by_pid: pid 2073                                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_exit_message: session 0 channel 0 pid 2073                                                                                   
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: request exit-status confirm 0                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_exit_message: release channel 0                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: write failed                                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: close_write                                                                                                               
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: output open -> closed                                                                                                     
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: send close                                                                                                                
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug3: channel 0: will not send data after close                                                                                            
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: rcvd close                                                                                                                
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug3: channel 0: will not send data after close                                                                                            
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: is dead                                                                                                                   
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: gc: notify user                                                                                                           
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_by_channel: session 0 channel 0                                                                                              
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_close_by_channel: channel 0 child 0                                                                                          
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: session_close: session 0 pid 0                                                                                                       
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: gc: user detached                                                                                                         
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: is dead                                                                                                                   
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug2: channel 0: garbage collecting                                                                                                        
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: channel 0: free: server-session, nchannels 1                                                                                         
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug3: channel 0: status: The following connections are open:\r\n  #0 server-session (t4 r256 i3/0 o3/0 fd 7/7 cfd -1)\r\n                  
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug3: channel 0: close_fds r 7 w 7 e -1 c -1                                                                                               
Oct  4 14:29:46 arm auth.info sshd[2070]: Connection closed by 192.168.1.12                                                                                                             
Oct  4 14:29:46 arm auth.debug sshd[2070]: debug1: do_cleanup                                                                                                                           
Oct  4 14:29:46 arm auth.info sshd[2070]: Closing connection to 192.168.1.12 

Escluderei FileZilla come un problema. Prova con il sftpcomando ( sftp host.name.here). Se qualcosa non riesce, potrebbe anche darti informazioni migliori.
Patrick,

leggermente estraneo: OpenSSH 4.7p1 ha 6 anni - per motivi di sicurezza si prega di utilizzare qualcosa di più recente. Per quanto riguarda la domanda: sftp-serversembra che esca prematuramente:Oct 4 14:29:46 arm auth.debug sshd[2070]: debug1: Received SIGCHLD.
peterph

@peterph - Ieri ho aggiornato all'ultimo openssh (6.3p1) ieri e ho riscontrato gli stessi problemi.
Michael,

@Patrick - Ho provato il comando sftp dall'host alla destinazione e i risultati sono gli stessi. Il server chiude la connessione dopo l'autenticazione.
Michael,

@Michael potresti correre sshd strace -f?
peterph

Risposte:


9

Mentre questa è più una soluzione alternativa che una risposta diretta al tuo problema, proverei ad usare il server sftp interno anziché uno esterno. Dato che si tratta di un sistema incorporato, probabilmente ha più senso farlo comunque.

Nel tuo sshd_config, basta aggiungere:

Subsystem sftp internal-sftp

In questo modo puoi tralasciare il file binario sftp e risparmiare spazio.


Sembra che non funzioni "errore: sottosistema: impossibile stat internal-sftp: nessun file o directory." Non so perché sia ​​successo, ma non sembra essere un'opzione di compilazione / configurazione ...
Michael,

@Michael hrm, è strano. Forse è un'opzione di compilazione. Non ho mai visto un OpenSSH senza di esso.
Patrick,

Ho aggiornato all'ultimo openssh (6.3p1) e internal-sftp funziona come previsto.
Michael,

Un possibile motivo per cui il server sftp non si avvia è quando gli utenti non hanno una shell, ad esempio se è impostato su / bin / false. In questo caso devi usare "internal-sftp".
Zrin,
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