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pythonpostgresqlhashcgi

Can't retrieve hashed password from postgreSQL Database with Python


So I'm writing a simple login script in python cgi. It wasn't working on the localhost, (showing 500 error) so running the code on its own revealed there were code issues. The code is as follows:

#!/usr/bin/python2.7
import cgi
import cgitb
import hashlib
import psycopg2
from dbconfig import *
cgitb.enable()
print "Content-Type: text/html"


def checkPass():
    email = "[email protected]"
    password = "blahblah"
    password = hashlib.sha224(password.encode()).hexdigest()
    result = cursor.execute('SELECT * FROM logins WHERE email=%s passhash=%s') % (email, password)
    print str(result)


if __name__ == "__main__":
    conn_string = "host=%s dbname=%s user=%s password=%s" % (host, database, dbuser, dbpassword)
    conn = psycopg2.connect(conn_string)
    cursor = conn.cursor()
    checkPass()

The line that the program gets stuck on is the cursor.execute of the postgre query. The error that is shown is as follows:

Traceback (most recent call last):
  File "login.py", line 28, in <module>
    checkPass()
  File "login.py", line 20, in checkPass
    result = cursor.execute('SELECT * FROM logins WHERE email=%s passhash=%s') % (email, password)
ProgrammingError: syntax error at or near "passhash"
LINE 1: SELECT * FROM logins WHERE email=%s passhash=%s

And it should be noted that it points to passhash. I tried entering the query directly into the db in psql console as:

SELECT * FROM logins WHERE passhash=storedhashedcode;

However, this returns an error about a column of the name of the hash (i.e e342hefheh43hfhfhefherf....etc) not existing. What am I doing wrong here? The only thing I can think of is hashes being stored differently.

Note - here's the code I used to store the password etc, if that helps:

email = "[email protected]"
allpass = "blahblah"
password = hashlib.sha224(allpass.encode()).hexdigest()
cursor.execute('INSERT INTO logins (email, passhash) VALUES (%s, %s);', (email, password)) 
conn.commit()

Any help would be greatly appreciated!

UPDATE:

As suggested by Decly, I've changed the query to:

result = cursor.execute('SELECT * FROM logins WHERE email=%s AND passhash=%s') % (email, password)

This now produces the error:

ProgrammingError: column "s" does not exist
LINE 1: SELECT * FROM logins WHERE email=%s AND passhash=%s

So it's obviously using s as a column for some reason. Why is it not taking in my variable names?


Solution

  • In:

    'SELECT * FROM logins WHERE email=%s passhash=%s'
    

    You are missing a AND in the boolean expression:

    'SELECT * FROM logins WHERE email=%s AND passhash=%s'
    

    When you write the query in psql you are missing the quotes for the string literal, so postgresql is inferring a column name, you should write:

    SELECT * FROM logins WHERE passhash='storedhashedcode';
    

    You are also putting the parentesis in the wrong place, the python sentence should be:

    result = cursor.execute('SELECT * FROM logins WHERE email= %s AND passhash= %s', (email, password))