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I stopped using web.py after I had to correct Aaron when he recommended a 'session' implementation that had a massive gaping security hole. http://groups.googl

I stopped using web.py after I had to correct Aaron when he recommended a 'session' implementation that had a massive gaping security hole. http://groups.google.com/group/webpy/browse_thread/thread/2fcbcb60a99a1c79/4d2a53b33adc3cdb?#4d2a53b33adc3cdb http://groups.google.com/group/webpy/browse_thread/thread/2f... If he couldn't spot that when he posted, I don't trust him to spot any other problems with web.py

bayareaguy 19y ago
For a second I didn't get what the big deal was here. Sure you have to keep your pickled python objects in a secure place on your server. Sure you could have problems if someone could get at those, but they would need to crack your server first and then figure out how your app worked. If they could do that you're hosed anyway... Then it hit me. He was suggesting you give the pickled object back to the client in the session cookie and load whatever the client sends later right back into the interpreter. Whee!
- icky 19y ago
  > He was suggesting you give the pickled object back to the client in the session cookie and load whatever the client sends later right back into the interpreter. Whee! I've done that with signed cookies.
  - inklesspen 19y ago
    There wasn't any encryption involved in his suggestion. :D
  - bayareaguy 19y ago
    I imagine you didn't store any per-session state on the server as well, so I'm curious about what you used to validate the cookie.
    - icky 19y ago
      I secretly salted the cookie. Think HMAC, though I used two completely different keys, rather than generating them from one key, added an optional step of appending the client's IP address after the first hashing (with the first key) and before the second one. (The second hashing in HMAC is designed to prevent collision attacks (even on weak algorithms like MD5), since you'd essentially have to find a fraudulent input that collides twice: once when hashed, and once more when its hash is hashed). My implementation also allowed the data to span an arbitrary number of ~4kb cookies). Firefox maxed out at around 0.5MB, though if you're using that much session data, you may want to rethink your app design... ;)
juanpablo 19y ago
He is doing a good job so far. Anyway, I believe he isn't the only developer of web.py anymore.

bayareaguy 19y ago

For a second I didn't get what the big deal was here. Sure you have to keep your pickled python objects in a secure place on your server. Sure you could have problems if someone could get at those, but they would need to crack your server first and then figure out how your app worked. If they could do that you're hosed anyway... Then it hit me. He was suggesting you give the pickled object back to the client in the session cookie and load whatever the client sends later right back into the interpreter. Whee!

icky 19y ago
> He was suggesting you give the pickled object back to the client in the session cookie and load whatever the client sends later right back into the interpreter. Whee! I've done that with signed cookies.
- inklesspen 19y ago
  There wasn't any encryption involved in his suggestion. :D
- bayareaguy 19y ago
  I imagine you didn't store any per-session state on the server as well, so I'm curious about what you used to validate the cookie.
  - icky 19y ago
    I secretly salted the cookie. Think HMAC, though I used two completely different keys, rather than generating them from one key, added an optional step of appending the client's IP address after the first hashing (with the first key) and before the second one. (The second hashing in HMAC is designed to prevent collision attacks (even on weak algorithms like MD5), since you'd essentially have to find a fraudulent input that collides twice: once when hashed, and once more when its hash is hashed). My implementation also allowed the data to span an arbitrary number of ~4kb cookies). Firefox maxed out at around 0.5MB, though if you're using that much session data, you may want to rethink your app design... ;)

juanpablo 19y ago

He is doing a good job so far. Anyway, I believe he isn't the only developer of web.py anymore.