Show HN: I made tarbackup.com for you, what do you think?

http://tarbackup.com

by nanch • 14 years ago

18 35 14 years ago

tarbackup.com

tisme4• 14 years ago

See: tarsnap.com

nanch10• 14 years ago

tarsnap looks nice. somebody else had mentioned that service too, I figured I'd go over some of the differences.

tarbackup is free, tarsnap is $0.30/GB/mo; tarbackup doesn't require a separate client download; tarbackup was made just for fun, tarsnap is commercial; tarbackup uses a private server, tarsnap uses S3

micheljansen2• 14 years ago

How are you going to keep it free? What guarantee do you give that after trusting my data to you, you won't decide that your bandwidth and storage costs are getting out of hand and discontinue the service?

Not trying to be a sour grape here and talk you down, but these questions matter if you see this as more than a hobby thing and are serious about it. If you plan to take this further: find a way to make it sustainable. If not: why not release the code?

tisme4• 14 years ago

Tarsnap is secure, made by someone who understands security. Backups are synonymous with reliability and security. Trusting an unknown entity with free backups on a service made 'for fun' makes me wonder:

- how long it will be around

- how you plan to stay alive in the long run

I really wonder if you've thought this one through. Backups are rarely if ever for fun, when you need them you need them badly.

zalew• 14 years ago

"tarbackup was made just for fun, tarbackup uses a private server" excelent selling points for a backup service.

ysleepy• 14 years ago

I see that you are passionate about this.

After I wrote a paragraph about how you could use the hardware for a shell server, static (octopress/jekyll) website hoster etc. I realised, that free backups are actually really awesome.

For people who cannot afford another service or dont have access to a credit card or else. Also fpr my most important data like code as a second backup if all goes wrong.

Thanks for the service, I will probably actually use it.

But it being a fun project and only behind 5mbit upload, this is obviously not a professional solution or could be offered for money.

nanch10• 14 years ago

"Free backups are really awesome." love that line :)

My pleasure, I hope you do use it!

We'll see how much use it gets. I could put the box on a 100mbps if people start using it.

Cyranix3• 14 years ago

Your Git repo doesn't inspire confidence for usage by the public at large. If you want to continue using it, I would recommend that you change it over to friends-and-family access while you improve it.

A few things that don't impress me right off the bat:

  * text file for queue of users to create
  * not accepting passwords with non-alphanumeric characters 
    (and also not having the knowledge to recognize a use case
    for a regular expression)
  * using a static salt

To be honest, I just stopped looking at this point. That's all without actually looking at the front-end of it (which has several typos, by the way -- when you're selling yourself to a very large audience, every detail counts).

nanch10• 14 years ago

Thank you for looking over the code and providing your honest criticism.

* the textfile doesn't seem like a problem to me, just another version of a DB, what would be better?

* I updated the password to accept any password, not just alphanumerics

* I updated submit.php to use a random 16-character salt rather than the static salt

I'll look over the site to see if I can find those typos ;)

Cyranix3• 14 years ago

It doesn't seem to me that you're storing the per-user salt anywhere.

I'm glad you're working on a project that is fun for you. It will be an opportunity for you to learn quite a lot, but I would urge you to question your design choices and keep asking "How could this be done better?". Read about how other people have approached similar problems.

Get a small group of friends, family, and other technical acquaintances to pick this apart. I wouldn't endorse this for the general public.

viraptor• 14 years ago

> the textfile doesn't seem like a problem to me, just another version of a DB, what would be better?

It's not atomic at all. You could at least use bdb, or sqlite.

genwin4• 14 years ago

Thanks! I understand what this service is: free "cloud" backup, no guarantees. I have no problem with the latter part, given the former part. I'll use it accordingly and appreciate your gift.

nanch10• 14 years ago

thank you! let me know if you have any problems or suggestions! my email is president@nanch.com

jarek3• 14 years ago

> backup, no guarantees

What's the use?

genwin4• 14 years ago

It's useful for a secondary or tertiary backup.

JoachimSchipper2• 14 years ago

From your "how to use" page:

    # echo mysupersecretkey > /backups/key
    # openssl enc -aes-256-cbc -salt -in fullbackup.tar.gz \
        -out fullbackup.tar.gz.enc -pass file:/backups/key

Please don't do this. openssl -aes-256-cbc is not a strong key derivation algorithm, so you need to use keys with much higher entropy (dd if=/dev/random of=/backups/key); an attacker can run through a dictionary of common passwords ridiculously quickly, thousands of times faster than when you're using a proper key derivation algorithm, e.g. bcrypt/scrypt/PBKDF2 to generate the key. If you do want to derive it from something akin to a password.

More seriously, openssl -aes-256-cbc does not do any integrity protection; in fact, an attacker can more or less flip any bits of his choosing in the ciphertext to flip those same bits in the plaintext. (Yes, I'm aware it's a tiny bit more complicated than that.)

It is possible to fix both of the above, but may I recommend gpg --symmetric as a simple and reasonably secure alternative?

nanch10• 14 years ago

Great feedback, I'll change the "how to" ASAP after some reading on the subject. Is there a secure command option that I can use with openssl instead of -aes-256-cbc?

I originally tried to provide an example for openssl and gpg, but the gpg example ended up with a dependency on X11 via a dependency on pinentry so I took it out for simplicity.

JoachimSchipper2• 14 years ago

OpenSSL sadly does not offer any authenticated encryption modes, so you cannot just replace -aes-256-cbc by something and be secure. There are basically two things that work: either authenticate the ciphertext [1] by having the user store a secure hash of each archive ("openssl sha512"), or switch to public-key crypto.

Since the first is just inviting disaster - users aren't actually going to verify hashes - I recommend the second option. It's possible to build this on top of "openssl pkeyutl", but gpg is a lot nicer. If I were you, I'd just use gpg - some OSes/distros may pull in lots of stuff, but requiring a running (as opposed to installed) X server to run gpg is incredibly unlikely.

[1] Always authenticate the ciphertext, never (just) the plaintext. See "padding oracle attack" for one practical reason why - getting a recognizable error when decrypting mangled ciphertext allows one to fully recover the plaintext. "Recognizable error" includes timing information. Just make sure you always authenticate the ciphertext.

Show HN: I made tarbackup.com for you, what do you think?

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