parse_qs ( qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace' ) ¶ Unmatched square brackets in the netloc attribute will raise aĬhanged in version 3.3: The fragment is now parsed for all URL schemes (unless allow_fragment isįalse), in accordance with RFC 3986. See section Structured Parse Results for more information on the result ThisĬlass has the following additional read-only convenience attributes: Attribute The return value is actually an instance of a subclass of tuple. Or query component, and fragment is set to the empty string in Instead, they are parsed as part of the path, parameters
If the allow_fragments argument is false, fragment identifiers are not (text or bytes) as urlstring, except that the default value '' isĪlways allowed, and is automatically converted to b'' if appropriate.
Used only if the URL does not specify one. The scheme argument gives the default addressing scheme, to be Superseder: Denial of service in urllib.request.> from urllib.parse import urlparse > urlparse ( '//%7E guido/Python.html' ) ParseResult(scheme='', netloc='path='/%7Eguido/Python.html', params='', query='', fragment='') > urlparse ( '%7E guido/Python.html' ) ParseResult(scheme='', netloc='', path='params='', query='', fragment='') > urlparse ( 'help/Python.html' ) ParseResult(scheme='', netloc='', path='help/Python.html', params='', query='', fragment='') Thanks Ben Caller for the report, I credited you in my fix -) This issue is a duplicate of bpo-39503 which has a PR. I'd also suggest using a raw string instead: I have been advised that DoS issues can be added to the public bug tracker since there is no privilege escalation, but should still have the security label.Ī smaller change to the regex would be to replace the "(?.*,)*" with "(?:*,)*".
Please report security issues to so that the security team can analyze and triage it to be made public. Rx = re.compile('basic+realm=(?)(*)\\2', re.I)Īuthor: Karthikeyan Singaravelan (xtreak) * Opener.open(" As such, python applications using urllib.request may need to be careful not to visit malicious servers. The maximum length of comma string that can fit in a response header is 65509, which would take my computer just 6E+19706 years to complete.įrom rver import BaseHTTPRequestHandler, HTTPServer Showing an exponential relationship O(2^x) ! I tested the length of time (seconds) to complete for different numbers of commas in the string: Which causes catastrophic backtracking and takes a large amount of CPU time to process.
Input from the WWW-Authenticate or Proxy-Authenticate headers of HTTP responses will reach the regex via the http_error_auth_reqed method as long as the header value starts with "basic ". Showing that there are many different ways to match a long sequence of commas. The regular expression is vulnerable to malicious inputs which cause denial of service (REDoS). Denial of service in Īnselmo Melo, bc, mgorny, mrabarnett, vstinner, xtreakĬreated on 01:45 by bc, last changed 14:59 by admin.
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