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Revision 942cc04ae44825ea120e3a19a80c9b348b8194d0 authored by Ned Deily on 11 March 2018, 18:28:53 UTC, committed by larryhastings on 11 March 2018, 18:28:53 UTC
* Prevent low-grade poplib REDOS (CVE-2018-1060)

The regex to test a mail server's timestamp is susceptible to
catastrophic backtracking on long evil responses from the server.

Happily, the maximum length of malicious inputs is 2K thanks
to a limit introduced in the fix for CVE-2013-1752.

A 2KB evil response from the mail server would result in small slowdowns
(milliseconds vs. microseconds) accumulated over many apop calls.
This is a potential DOS vector via accumulated slowdowns.

Replace it with a similar non-vulnerable regex.

The new regex is RFC compliant.
The old regex was non-compliant in edge cases.

* Prevent difflib REDOS (CVE-2018-1061)

The default regex for IS_LINE_JUNK is susceptible to
catastrophic backtracking.
This is a potential DOS vector.

Replace it with an equivalent non-vulnerable regex.

Also introduce unit and REDOS tests for difflib.

Co-authored-by: Tim Peters <tim.peters@gmail.com>
Co-authored-by: Christian Heimes <christian@python.org>.
1 parent f584ecd
History
Tip revision: 942cc04ae44825ea120e3a19a80c9b348b8194d0 authored by Ned Deily on 11 March 2018, 18:28:53 UTC
[3.4] bpo-32981: Fix catastrophic backtracking vulns (GH-5955) (#6035)
Tip revision: 942cc04

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