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points by BoppreH 2 days ago | 0 comments

No, that's just more in-band signaling!

Some badly designed password hashing algorithms (cough bcrypt cough) have maximum password lengths, ignoring everything after X characters. So it could happen that I set my password to a 100-character string, it gets saved as "==DANGEROUS_CRYPT_ERROR_length==", and then anybody can log in to my account by entering an unrelated long string that returns the same "error".

If a function promises a string result, it should only provide a string if the function succeeded. The null was much better than magic strings.

[–] dns_snek 2 days ago

I know, it's bad. I agree that it should've stayed NULL. But if you really really really think you have an acceptable reason to do something like this (and you probably don't), the least you can do is use a non-trivial token.

[–] BoppreH 2 days ago

If I was really desperate and could only return a valid string, I would probably use a message and add a random component to avoid ever matching two errors. Like SQL, where null != null.