Bug 662886

Summary:	<dev-python/cryptography-2.3: possible tag truncation security bug in AEAD API
Product:	Gentoo Security	Reporter:	Thomas Deutschmann (RETIRED) <whissi>
Component:	Vulnerabilities	Assignee:	Gentoo Security <security>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	python
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
URL:	https://github.com/pyca/cryptography/pull/4342
Whiteboard:
Package list:		Runtime testing required:	---

Description Thomas Deutschmann (RETIRED) gentoo-dev

2018-08-05 22:44:16 UTC

Description of problem:
The finalize_with_tag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalize_with_tag an attacker could craft an invalid payload with a shortened tag (e.g. 1 byte) such that they would have a 1 in 256 chance of passing the MAC check. GCM tag forgeries can cause key leakage.

Comment 1 Thomas Deutschmann (RETIRED) gentoo-dev

2018-08-05 22:45:23 UTC


*** This bug has been marked as a duplicate of bug 662564 ***