662886 – <dev-python/cryptography-2.3: possible tag truncation security bug in AEAD API

Bug 662886 - <dev-python/cryptography-2.3: possible tag truncation security bug in AEAD API

Summary: <dev-python/cryptography-2.3: possible tag truncation security bug in AEAD API

Status:	RESOLVED DUPLICATE of bug 662564

Alias:	None

Product:	Gentoo Security
Classification:	Unclassified
Component:	Vulnerabilities (show other bugs)
Hardware:	All Linux

Importance:	Normal normal (vote)
Assignee:	Gentoo Security

URL:	https://github.com/pyca/cryptography/...
Whiteboard:
Keywords:

Depends on:
Blocks:

Reported:	2018-08-05 22:44 UTC by Thomas Deutschmann (RETIRED)
Modified:	2018-08-05 22:45 UTC (History)
CC List:	1 user (show)

See Also:
Package list:
Runtime testing required:	---

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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 ***