Bug 1758587

Summary:	OpenSSL will send unexpected alert for too short ciphertext with specific ciphersuites [rhel-8]
Product:	Red Hat Enterprise Linux 8	Reporter:	Alicja Kario <hkario>
Component:	openssl	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED ERRATA	QA Contact:	Alicja Kario <hkario>
Severity:	low	Docs Contact:
Priority:	low
Version:	8.0	Keywords:	Triaged
Target Milestone:	rc	Flags:	pm-rhel: mirror+
Target Release:	8.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	openssl-1.1.1c-9.el8	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:
Clones:	1758602 (view as bug list)		Environment:
Last Closed:	2020-04-28 16:52:04 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1758602

Description Alicja Kario 2019-10-04 14:42:37 UTC

Description of problem:
When the ciphertext is too small to contain IV, MAC and padding, openssl will send decryption_failed alert instead of the bad_record_mac.
This happens only for ciphers that do not use the "stiched" implementation of a cipher that combines the symmetric cipher with the HMAC.

Version-Release number of selected component (if applicable):
openssl-1.1.1c-2.el8

How reproducible:
always

Steps to Reproduce:
1. send a 16 bytes long ciphertext in a TLS record after negotiating TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 or TLS_RSA_WITH_3DES_EDE_CBC_SHA

Actual results:
server replies with decryption_failed

Expected results:
bad_record_mac alert

Additional info:
since the check is based on publicly visible data (the length of ciphertext), the difference in alert returned can't be used as a padding oracle for decryption

Comment 1 Tomas Mraz 2019-10-04 15:05:00 UTC

Trivial fix.

Comment 11 errata-xmlrpc 2020-04-28 16:52:04 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:1840

Comment 12 Fedora Update System 2020-05-29 00:57:11 UTC

FEDORA-EPEL-2020-ff94ccbdec has been pushed to the Fedora EPEL 7 stable repository.
If problem still persists, please make note of it in this bug report.