If you modify a flow.xml by hand and put a plaintext value into any sensitive property, then the next time you start NiFi and it saves the flow.xml.gz NiFi will encrypt the plaintext value. Any change to the flow (such as starting, stopping, reconfiguring, creating, deleting or moving a processor) will cause NiFi to do this.
It's a lot less secure than encrypting the password in your Ruby script, because the plaintext password will exist on disk for some amount of time, but I wanted to let you know that NiFi will do this. -- Mike On Thu, Jul 14, 2016 at 2:46 PM, Andy LoPresto <[email protected]> wrote: > Happy to help, Brett. I always like seeing people use the software in a > secure manner. If you can, you may want to publish your tool on GitHub. > While you don’t have to submit it back for inclusion in NiFi itself (and if > it’s a Ruby tool, it may not be correct for inclusion), there are many > people who share their personal extensions and tools for administering NiFi > with the public. > > I remembered I had written some Ruby code using OpenSSL for key derivation > and encryption verification for an earlier ticket, so take a look here [1] > for some examples that may help. Basically, you switch out the PBKDF2 > invocation with the EVP_BytesToKey (aka PKCS #5 v1.5 PBKDF1) and use an > empty salt, and change the cipher to AES-256-CBC. > > [1] > https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/resources/openssl_pbkdf2.rb > > > Andy LoPresto > [email protected] > *[email protected] <[email protected]>* > PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4 BACE 3C6E F65B 2F7D EF69 > > On Jul 14, 2016, at 2:23 PM, Hite, Brett <[email protected]> wrote: > > Hi Andy, > > I think I need a little time to review your post, but this sounds exactly > like what I was looking for. I was looking for a way to create the > encrypted value stored within the “enc{ … }” tag. Thank you for translating > my question and for the quick response! > > *Brett Hite* > [email protected] > > *From:* Andy LoPresto [mailto:[email protected] <[email protected]>] > > *Sent:* Thursday, July 14, 2016 2:14 PM > *To:* [email protected] > *Subject:* Re: Passwords in EncryptContent > > Hi Brett, > > I’m not sure I understand your question completely, so let me try to > describe it and you can correct me where I get it wrong. > > You have some deployment system which uses a Ruby process to replace > tokens in a flow template with the “real” values, and one of the values > that needs to be set is the password used by an EncryptContent processor > configured with password-based encryption. (This much makes sense to me). > > What I am confused by is your reference to “hash values”. While in many > situations (most web applications, user databases, etc.) cryptographic > hashing is the correct way to protect a password or other sensitive value > when persisting to disk, this is only appropriate if the raw sensitive > value does not need to be retrieved. However, in this scenario, the > password must be usable in raw form to derive the key to encrypt content, > so it cannot be stored in a “hash value” format (irreversible), but rather > encrypted (reversible). > > In order to persist the encrypted form of this password, you need to run > the same encryption algorithm and use the same key as NiFi does. These are > exposed to you in nifi.properties using the keys “nifi.sensitive.props.key” > and > “nifi.sensitive.props.algorithm”. By default the key is blank, and the > algorithm is “PBEWITHMD5AND256BITAES-CBC-OPENSSL” — in English, that’s > Password-Based Encryption using a single iteration of MD5 digest over the > password (the previous property) and salt (none in this case), taking the > resulting 32 hexadecimal characters (16 bytes) as the first half of a 256 > bit (32 byte) key, then calculating the MD5 of this value concatenated with > the raw password and raw salt again as the second half. [1][2] That key is > now used with AES-256 in CBC mode [3] to encrypt the raw sensitive values > and persist them in the form “enc{hex-encoded-ciphertext}” in the flow (see > below for example). If you feel at this point that the default key > derivation function is not sufficiently strong, know that I agree with you > and have opened a Jira to increase the strength of this process [4]. > > Anyway, to answer (what I believe is your question), you can write Ruby > code to populate your template with the encrypted value by retrieving the > sensitive properties key from nifi.properties, use the Ruby OpenSSL > bindings [5] to derive the key and encrypt the password, and then encode it > in hexadecimal and wrap it with the “enc{“ and “}” tags. > > I would also suggest you look at the Variable Registry [6][7], upcoming > encrypted configuration files [8], and deterministic templates [9][10], as > these may provide an easier way to perform what you are looking for, or at > least inform your next steps if you wish to keep your Ruby template system > and move forward in a compatible manner. > > If this didn’t answer your question (or raised others), please reply and > I’ll filter my thoughts through someone with a more human understanding of > the system. > > > [1] https://www.openssl.org/docs/manmaster/crypto/EVP_BytesToKey.html > [2] http://security.stackexchange.com/a/117654/16485 > [3] > https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_Block_Chaining_.28CBC.29 > [4] https://issues.apache.org/jira/browse/NIFI-1465 > [5] http://ruby-doc.org/stdlib-2.0.0/libdoc/openssl/rdoc/OpenSSL.html > [6] https://cwiki.apache.org/confluence/display/NIFI/Variable+Registry > [7] https://github.com/apache/nifi/pull/571 > [8] https://issues.apache.org/jira/browse/NIFI-1831 > [9] > https://cwiki.apache.org/confluence/display/NIFI/Configuration+Management+of+Flows > > <processor> > <id>206f32b5-9f72-4762-a1d5-711f8669db60</id> > <name>EncryptContent</name> > <position x="1101.0" y="176.0"/> > <styles/> > <comment/> > <class>org.apache.nifi.processors.standard.EncryptContent</class> > ... > <property> > <name>Encryption Algorithm</name> > <value>AES_GCM</value> > </property> > <property> > <name>Password</name> > > <value>enc{3832072F21CB7448E3C268287AF7F2F38359EB7F7E0F22CCFF2432EBC358335A0616B5CDCC895827FE0B1478901D364A}</value> > </property> > </processor> > > > > Andy LoPresto > [email protected] > *[email protected] <[email protected]>* > PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4 BACE 3C6E F65B 2F7D EF69 > > > On Jul 14, 2016, at 1:23 PM, Hite, Brett <[email protected]> wrote: > > Hello, > > I have a flow file that is created from a Ruby template file > (flow.xml.erb). The template contains variables that the user can set that > then get populated when NiFi is set up. I have an EncryptContent processor > and would like to create a template variable for the Password property. > Ideally, the user would say “password = some_password” and the template > variable would evaluate to the hash value stored in the actual flow file. > > Is there a way that I can calculate the hash value given a plain text > password? I’ve looked around and haven’t found too much. The NiFi > Administration Guide has an Encryption Configuration section that doesn’t > quite answer my question. > > Thanks, > > *Brett Hite* > [email protected] > > >
