view roundup/cgi/exceptions.py @ 5201:a9ace22e0a2f

issue 2550690 - Adding anti-csrf measures to roundup following https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet and https://seclab.stanford.edu/websec/csrf/csrf.pdf Basically implement Synchronizer (CSRF) Tokens per form on a page. Single use (destroyed once used). Random input data for the token includes: system random implementation in python using /dev/urandom (fallback to random based on timestamp as the seed. Not as good, but should be ok for the short lifetime of the token??) the id (in cpython it's the memory address) of the object requesting a token. In theory this depends on memory layout, the history of the process (how many previous objects have been allocated from the heap etc.) I claim without any proof that for long running processes this is another source of randomness. For short running processes with little activity it could be guessed. last the floating point time.time() value is added. This may only have 1 second resolution so may be guessable. Hopefully for a short lived (2 week by default) token this is sufficient. Also in the current implementation the user is notified when validation fails and is told why. This allows the roundup admin to find the log entry (at error level) and try to resolve the issue. In the future user notification may change but for now this is probably best.
author John Rouillard <rouilj@ieee.org>
date Sat, 18 Mar 2017 16:59:01 -0400
parents 65fef7858606
children 32f95ec6bd8e
line wrap: on
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"""Exceptions for use in Roundup's web interface.
"""

__docformat__ = 'restructuredtext'

from roundup.exceptions import LoginError, Unauthorised
import cgi

class HTTPException(Exception):
    pass

class Redirect(HTTPException):
    pass

class NotFound(HTTPException):
    pass

class NotModified(HTTPException):
    pass

class DetectorError(Exception):
    """Raised when a detector throws an exception.
Contains details of the exception."""
    def __init__(self, subject, html, txt):
        self.subject = subject
        self.html = html
        self.txt = txt

class FormError(ValueError):
    """An 'expected' exception occurred during form parsing.

    That is, something we know can go wrong, and don't want to alarm the user
    with.

    We trap this at the user interface level and feed back a nice error to the
    user.

    """
    pass

class SendFile(Exception):
    """Send a file from the database."""

class SendStaticFile(Exception):
    """Send a static file from the instance html directory."""

class SeriousError(Exception):
    """Raised when we can't reasonably display an error message on a
    templated page.

    The exception value will be displayed in the error page, HTML
    escaped.
    """
    def __str__(self):
        return """
<html><head><title>Roundup issue tracker: An error has occurred</title>
 <link rel="stylesheet" type="text/css" href="@@file/style.css">
</head>
<body class="body" marginwidth="0" marginheight="0">
 <p class="error-message">%s</p>
</body></html>
"""%cgi.escape(self.args[0])

# vim: set filetype=python sts=4 sw=4 et si :

Roundup Issue Tracker: http://roundup-tracker.org/