diff --git a/Doc/Sdi/gettingStarted.xml b/Doc/Sdi/gettingStarted.xml index 1f41627a9f563fa7337806ed35ce71eae6363969..1e3afc176248f0c6972c86a5dbdb20e3d73aa351 100644 --- a/Doc/Sdi/gettingStarted.xml +++ b/Doc/Sdi/gettingStarted.xml @@ -17,6 +17,72 @@ access to two virtual machines to mimic client provider and replication scenarios.</para> + <para>If you do not yet have a public/private <acronym>ssh</acronym> key + pair the <command>ssh-keygen</command> command is your friend. It allows + for generating a pair inside your <filename>~/.ssh</filename> + subdirectory. Working on a network drive your first problem may be + inappropriate file permissions of and inside your ~/.ssh directory:</para> + + <screen>mistudent@w10m:~/.ssh$ pwd +/stud/mistudent/.ssh +mistudent@w10m:~/.ssh$ ls -al +total 24 +drwxrwx---+ 2 mistudent mi 0 Okt 17 17:45 . +drwx------+ 32 mistudent mi 0 Okt 17 17:44 .. +-rwxrwx---+ 1 mistudent mi 396 Okt 17 17:45 authorized_keys +-rwxrwx---+ 1 mistudent mi 1675 Okt 17 17:38 id_rsa +-rwxrwx---+ 1 mistudent mi 396 Okt 17 17:38 id_rsa.pub</screen> + + <para>The permissions of the directory itself and the files within are too + open . The <command>sshd</command> daemon process will deny remote access + due to possible security implications. Unfortunately the standard + <command>chmod</command> command from UNIX does not help on modern + <abbrev>cifs</abbrev> based network file systems using extended ACLs. We + may ask <command>getfacl</command> for details:</para> + + <screen>mistudent@w10m:~/.ssh$ getfacl authorized_keys +# file: authorized_keys +# owner: mistudent +# group: mi +user::rwx +user:mistudent:rwx +group::--- +group:users:--- +mask::rwx +other::---</screen> + + <para>The counterpart <command>setfacl</command> allows for revoking + permissions <abbrev>e.g.</abbrev> on + <filename>authorized_keys</filename>:</para> + + <screen>mistudent@w10m:~/.ssh$ setfacl -m user:mistudent:--- authorized_keys +mistudent@w10m:~/.ssh$ setfacl -m user::rw- authorized_keys +mistudent@w10m:~/.ssh$ getfacl authorized_keys +# file: authorized_keys +# owner: mistudent +# group: mi +user::rw- +user:mistudent:--- +group::--- +group:users:--- +mask::--- +other::--- + +mistudent@w10m:~/ssh$ ls -al authorized_keys +-rw-------+ 1 mistudent mi 396 Okt 17 17:45 authorized_keys</screen> + + <para>Addressing each file and the directory itself in a similar fashion + leads to:</para> + + <screen>mistudent@w10m:~/.ssh$ ls -al +total 32 +drwx------+ 2 mistudent mi 0 Okt 17 17:44 . +drwx------+ 32 mistudent mi 0 Okt 17 17:44 .. +-rw-------+ 1 mistudent mi 1132 Okt 17 17:40 authorized_keys +-rw-------+ 1 mistudent mi 1679 Okt 11 14:46 id_rsa +-rw-r--r--+ 1 mistudent mi 396 Okt 11 14:46 id_rsa.pub +-rw-------+ 1 mistudent mi 442 Okt 11 14:49 known_hosts</screen> + <para>Access to these virtual machines is initially being controlled by password. A client will allow you to connect:</para>