| Subject: | Bug in Crypt::RSA::Key::Private::SSH serialize function |
| Date: | Sat, 9 Jul 2011 18:41:22 +0000 |
| To: | "bug-Crypt-RSA [...] rt.cpan.org" <bug-Crypt-RSA [...] rt.cpan.org> |
| From: | "Wallette, Nicholas" <Nicholas.Wallette [...] chenega.com> |
The serialize function does not interpret the Cipher parameter correctly. According to the documentation in Crypt::RSA::Key::Private.pm, in the new() function, the Cipher parameter is supposed to be: "Name of the symmetric cipher in which the private key is encrypted (or should be encrypted)."
The code in Crypt::RSA::Key::Private::SSH serialize() seems to expect this to be a number serving as a key in the %CIPHERS hash.
Line 113 in SSH.pm checks $passphrase to see if it's provided, and if so, then checks $params{Cipher} for contents, providing a default value of 3 if not. (Note: On my system, this is apparently mapped to Crypt::DES3, which is also not the documented default of "Blowfish".)
Line 143, executed only if $cipher_type passes a Boolean truth test, then sets $cipher_name to be the value determined by $CIPHERS{$cipher_type).
If used according to the documentation's convention for the Cipher parameter, this will cause Line 143 to set $cipher_name = $CIPHERS{NAME_of_chosen_cipher}, which is not a number, and thus not a valid key in the CIPHERS hash, causing Line 145 to try and require "Crypt::", which obviously fails.
Here's a code snippet that will show this behavior:
#!/usr/bin/perl
use warnings;
use strict;
use Crypt::RSA::Key;
use Crypt::RSA::Key::Private::SSH;
my $obj = new Crypt::RSA::Key;
# Create an unencrypted key
my ($pub, $pri) = $obj->generate(
Identity => 'Some User <someuser@example.com>',
Size => 1024,
KF => 'SSH'
);
# Now try to encrypt this key
my $crypted = $pri->serialize(
Cipher => "Blowfish",
Password => "Hunter2"
);
This pertains to version 1.99 of the Crypt::RSA package.
Perl version is v5.12.3, x86_64-linux.
OS is Gentoo Linux, Kernel 2.6.38-gentoo-r6, built June 13th, 2011 using an up-to-date Portage snapshot.
Exact error message is:
Unsupported cipher '': Can't locate Crypt:: in @INC (@INC contains: lib /root/dev/pdb/../../../../../lib /etc/perl /usr/lib64/perl5/site_perl/5.12.3/x86_64-linux /usr/lib64/perl5/site_perl/5.12.3 /usr/lib64/perl5/vendor_perl/5.12.3/x86_64-linux /usr/lib64/perl5/vendor_perl/5.12.3 /usr/lib64/perl5/site_perl /usr/lib64/perl5/vendor_perl /usr/lib64/perl5/5.12.3/x86_64-linux /usr/lib64/perl5/5.12.3 /usr/local/lib/site_perl .) at /usr/lib64/perl5/site_perl/5.12.3/Crypt/RSA/Key/Private/SSH.pm line 145.
at ./testcase.pl line 19
A couple possible fixes:
1) Change Line 113 to read:
my $cipher_type = $passphrase eq '' ? '' : $params{Cipher} || 'Blowfish';
and Line 144 to read:
my $class = 'Crypt::' . $cipher_type;
2) Map $params{Cipher} to $cipher_type by something like this:
foreach my $type keys(%CIPHERS) { if $CIPHERS{$type} eq $params{Cipher} { $cipher_type = $type; } }
3) Change the documentation to suggest using the numerical index for Cipher, and a good way to find out what those are.
Nick Wallette
Systems Administrator
Chenega Logistics, LLC
3000 C Street, Suite 301
Anchorage, AK 99503
(907) 677-4928 Direct
(907) 903-1811 Cell
(907) 277-5706 Main
(907) 277-5700 Fax
nick.wallette@chenega.com<mailto:nick.wallette@chenega.com> Email
Message body is not shown because it is too large.