| Subject: | Taint breakage when used with Crypt::Rijndael or Crypt::OpenSSL::AES |
When used with taint enabled and with automatic salting (-salt = 1), the
random bytes used for salt are not untainted. When later used as part
of real key, the SvPOK(key) call used in the .xs files for
Crypt::Rijndael and Crypt::OpenSSL::AES returns false resulting in this
error (differs slightly between cipher modules):
"Key must be a scalar at /usr/lib/perl5/vendor_perl/5.8.8/Crypt/CBC.pm
line 367"
Here is a one-liner to trigger the error (remove the -T flag to see
it work correctly)
$ perl -Te 'use Crypt::CBC;$c=Crypt::CBC->new(-key=>"pw",
-cipher=>"Rijndael", -header=>"salt"); print unpack("H*",
$c->encrypt("test")), "\n";'
I suggest untainting $result in Crypt::CBC::_get_random_bytes(), as
shown in the following diff. (This double checks the length, as well.)
--- CBC.pm.orig 2007-09-27 17:24:32.000000000 -0500
+++ CBC.pm 2007-09-27 17:31:15.000000000 -0500
@@ -422,7 +422,9 @@
} else {
$result = pack("C*",map {rand(256)} 1..$length);
}
- $result;
+ # Clear taint and check length
+ $result =~ /^(.{$length})$/s or croak "Invalid length while gathering
$length randim bytes";
+ $result = $1;
}
sub _standard_padding ($$$) {