/ 
Net-SSH-AuthorizedKeysFile-0.12
River stage one • 1 direct dependent • 1 total dependent
/ Net::SSH::AuthorizedKey

NAME

Net::SSH::AuthorizedKey - Virtual Base Class for SSH Public Keys

SYNOPSIS

use Net::SSH::AuthorizedKey;

my $key = Net::SSH::AuthorizedKey->parse( $line );

if(defined $key) {
      # ssh-1 or ssh-2
    print "Key parsed, type is ", $key->type(), "\n";
} else {
    die "Cannot parse key '$line'";
}

DESCRIPTION

Net::SSH::AuthorizedKey is a virtual base class for ssh public keys. Real implementations of it are Net::SSH::AuthorizedKey::SSH1 and Net::SSH::AuthorizedKey::SSH2.

The only way to using it directly is by calling its parse() method, and handing it an authorized_keys string (aka a line from an authorized_keys file). If it recognizes either a ssh-1 or a ssh-2 type key, it will return a Net::SSH::AuthorizedKey::SSH1 or a Net::SSH::AuthorizedKey::SSH2 object. See their manual pages for instructions on how to use them.

IMPLEMENTATION REFERENCE

The key parsers implemented in this distribution are implemented similarily as the authorized_keys file parser in the openssh source distribution.

Openssh contains the authorized_keys parser in its auth2_pubkey.c file. The user_key_allowed2() function opens the file and reads it line by line, ignoring leading whitespace, empty and comment lines.

After that, if a line doesn't contain a plain key, the parser skips ahead until the first whitespace (zooming through quoted areas "..." and interpreting '\"' as an escaped quote), then skips this whitespace and tries to read a key one more time.

Regarding options, the Perl parser isn't as elaborate with semantic peculiarities as openssh's auth_parse_options(), but this might be added in the future.

NOTES FOR SUBCLASS DEVELOPERS

If you're just using Net::SSH::AuthorizedKey to parse keys, the following section doesn't concern you. It's only relevant if you add new subclasses to this package, on top of what's already provided.

Net::SSH::AuthorizedKey is a (semi-)virtual base class implements options handling for its SSH1 and SSH2 subclasses.

SSH key lines can contain options that carry values (like command="ls") and binary options that are either set or unset (like "no_agent_forwarding"). To distinguish the two, and to provide a set of allowed option names, the subclass has to implement the method option_type(), which takes an option name, and returns

  • undef if the option is not supported

  • "s" if the option is a "string" option that carries a value

  • 1 if the option is a binary option

The subclasses Net::SSH::AuthorizedKey::SSH1 and Net::SSH::AuthorizedKey::SSH2 are doing this already.

LEGALESE

Copyright 2005-2009 by Mike Schilli, all rights reserved. This program is free software, you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

2005, Mike Schilli <m@perlmeister.com>