Bug 1758602

Summary:	OpenSSL will send unexpected alert for too short ciphertext with specific ciphersuites [rhel-7]
Product:	Red Hat Enterprise Linux 7	Reporter:	Alicja Kario <hkario>
Component:	openssl	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED WONTFIX	QA Contact:	BaseOS QE Security Team <qe-baseos-security>
Severity:	low	Docs Contact:
Priority:	low
Version:	7.8	CC:	qe-baseos-security, tmraz
Target Milestone:	rc	Keywords:	Triaged
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Hardware:	Unspecified
OS:	Unspecified
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Clone Of:	1758587	Environment:
Last Closed:	2019-10-07 06:15:59 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:
Bug Depends On:	1758587
Bug Blocks:

Description Alicja Kario 2019-10-04 15:24:09 UTC

+++ This bug was initially created as a clone of Bug #1758587 +++

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

--- Additional comment from Tomas Mraz on 2019-10-04 15:05:00 UTC ---

Trivial fix.