Re: OpenVPN launching scripts

[Dominick Grift]

On Fri, 2013-01-11 at 10:50 +0100, Bruno Vernay wrote:
>  I am trying to allow OpenVPN to use Amazon Simple Notification
> Service
>  (SNS), so that each time a client connects to the VPN, OpenVPN
>  triggers a bash script that will use Amazon SNS.
>  
>  Amazon SNS is a Java program launched via bash scripts.
>  It is in aws/SimpleNotificationServiceCli/bin/ for the .sh and /lib for the .jar
>  
>  OpenVPN launches a script in /etc/openvpn/client-connect.
>  
>  
>  OpenVPN runs confined and I don't want to poke a big hole just to run SNS.
>  
>  So I tried to "confine" SNS and allow the transition from OpenVPN, but
>  it didn't went well. (config files bellow)
>  I wonder if it could be just as good to allow OpenVPN to escape its
>  confine to only call the relevant SNS script ?
>  
>  
>  From documentation and audit2allow I got to these configuration files.
>  But it still doesn't authorize the script to run and now the messages
>  triggers errors in audit2allow:
>  
>  libsepol.mls_from_string: invalid MLS context
>  libsepol.mls_from_string: could not construct mls context structure
>  libsepol.context_from_record: could not create context structure
>  libsepol.context_from_string: could not create context structure
>  libsepol.sepol_context_to_sid: could not convert
>  system_u:object_r:proc_t: to sid
>  libsepol.context_from_record: type op is not defined
>  libsepol.context_from_record: could not create context structure
>  libsepol.context_from_string: could not create context structure
>  libsepol.sepol_context_to_sid: could not convert system_u:object_r:op:s0 to sid
>  libsepol.context_from_record: type openvpn_ is not defined
>  libsepol.context_from_record: could not create context structure
>  libsepol.context_from_string: could not create context structure
>  libsepol.sepol_context_to_sid: could not convert
>  system_u:object_r:openvpn_:s0 to sid
>  libsepol.context_from_record: type shell_e is not defined
>  libsepol.context_from_record: could not create context structure
>  libsepol.context_from_string: could not create context structure
>  libsepol.sepol_context_to_sid: could not convert
>  system_u:object_r:shell_e:s0 to sid
>   
Strange question maybe but what test editor did you use to create this
policy?

It almost seems that your amz_sns.fc messes up the file context
specifications (some clients append hidden symbols)

Also make sure you end your fc file with a newline

>  
>  
>  $ cat amz_sns.fc
>  /opt/aws/SimpleNotificationServiceCli.*/bin/.*    --
>  gen_context(system_u:object_r:amz_sns_exec_t,s0)
>  /opt/aws/SimpleNotificationServiceCli.*/lib(/.*)?
>  gen_context(system_u:object_r:amz_sns_lib_t,s0)
>  
>  
>  $ cat amz_sns.te
>  policy_module( amz_sns, 1.0.0)
>  
>  require {
>          type openvpn_t;
>          type openvpn_tmp_t;
>          type shell_exec_t;
>  }
>  
>  type amz_sns_t;
>  type amz_sns_exec_t;
>  type amz_sns_lib_t;
>  
>  files_type(amz_sns_lib_t);
>  
>  domain_type(amz_sns_t)
>  domain_entry_file(amz_sns_t, amz_sns_exec_t)
>  
>  allow amz_sns_t amz_sns_exec_t:file { read execute entrypoint };
>  domain_auto_trans( openvpn_t, amz_sns_exec_t, amz_sns_t );
>  
>  role system_r types amz_sns_t;  # ???
>  
>  # The child process sends a signal to its parent as it dies
>  allow amz_sns_t openvpn_t:process sigchld;
>  
>  allow amz_sns_t openvpn_tmp_t:file write;   # For /tmp/debug
>  
>  allow amz_sns_t shell_exec_t:file { read open execute execute_no_trans
>  };  # Bash exec
>  
>  
>  Bruno
>  --
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