Note: This is a public test instance of Red Hat Bugzilla. The data contained within is a snapshot of the live data so any changes you make will not be reflected in the production Bugzilla. Email is disabled so feel free to test any aspect of the site that you want. File any problems you find or give feedback at
Bug 1534532 - Strong crypto settings
Summary: Strong crypto settings
Alias: None
Product: Fedora
Classification: Fedora
Component: Changes Tracking
Version: 28
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
Assignee: Nikos Mavrogiannopoulos
QA Contact:
Whiteboard: ChangeAcceptedF28, SystemWideChange
Depends On:
TreeView+ depends on / blocked
Reported: 2018-01-15 12:45 UTC by Jan Kurik
Modified: 2018-05-02 12:05 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Last Closed: 2018-05-02 12:05:17 UTC
Type: ---

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Bugzilla 1548016 0 unspecified CLOSED TB does not download emails from IMAP 2021-02-22 00:41:40 UTC
Red Hat Bugzilla 1549096 0 unspecified CLOSED FF and TB can't connect to several sites due to SSL_ERROR_WEAK_SERVER_EPHEMERAL_DH_KEY error 2021-02-22 00:41:40 UTC
Red Hat Bugzilla 1549242 0 unspecified CLOSED SSL connection failure: The Diffie-Hellman prime sent by the server is not acceptable (not long enough). 2021-02-22 00:41:40 UTC

Internal Links: 1548016 1549096 1549242

Description Jan Kurik 2018-01-15 12:45:56 UTC
This is a tracking bug for Change: Strong crypto settings
For more details, see:

This change is about updating the current system-wide crypto policy to disable legacy and unused cryptographic protocols.

Comment 1 Jan Kurik 2018-02-20 14:10:23 UTC
On 2018-Feb-20, we have reached the Fedora 28 Change Checkpoint: Completion deadline (testable).

At this point, all accepted changes should be substantially complete, and testable. Additionally, if a change is to be enabled by default, it must be enabled at Change Completion deadline as well.

Change tracking bug should be set to the MODIFIED state to indicate it achieved completeness.

Incomplete and non testable Changes will be reported to FESCo for 2018-Feb-23 meeting.

Comment 2 Fedora End Of Life 2018-02-20 15:38:28 UTC
This bug appears to have been reported against 'rawhide' during the Fedora 28 development cycle.
Changing version to '28'.

Comment 3 Zbigniew Jędrzejewski-Szmek 2018-02-23 15:16:32 UTC
* Mon Feb 12 2018 Nikos Mavrogiannopoulos <nmav> - 20180112-1.git386e3fe - Updated to apply the settings as in StrongCryptoSettings project. The restriction to TLS1.2, is not yet applied as we have no method to impose that in openssl.

So I guess this change is partially implemented.

Comment 4 Nikos Mavrogiannopoulos 2018-02-26 07:54:29 UTC
Not sure how to express that here.

Comment 5 Zbigniew Jędrzejewski-Szmek 2018-02-26 10:17:01 UTC
It seems to me that the missing bit is a smaller part of the Change. If that is true, I'd just update the Change page to clearly say which part is deferred, and proceed with the rest (i.e. set it to MODIFIED, fill in the Documentation section, etc.).

Comment 6 Nikos Mavrogiannopoulos 2018-02-26 10:33:08 UTC
Thanks. I've updated the change to document the contigency plan.

Comment 7 Vít Ondruch 2018-02-26 15:45:44 UTC
Since I updated my Rawhide last week, I have issues connecting to some sites using FF due to errors like:

An error occurred during a connection to ****.com. Při komunikaci protokolem SSL byl v inicializační zprávě typu Server Key Exchange obdržen slabý klíč typu Diffie-Hellman. Error code: SSL_ERROR_WEAK_SERVER_EPHEMERAL_DH_KEY

I have similar issues connecting my TB to the mail server:

An error occurred during a connection to

SSL received a weak ephemeral Diffie-Hellman key in Server Key Exchange handshake message.


I have not updated neither FF nor TB.

Comment 9 Nikos Mavrogiannopoulos 2018-02-27 10:38:46 UTC
The strong settings seem to affect VPNs as well (#1549242)

Comment 10 Jan Kurik 2018-03-06 08:58:20 UTC
On 2018-Mar-08 we reached the "Change Checkpoint: 100% Code Complete Deadline" milestone for Fedora 28 release. At this point all the Changes not at least in "ON_QA" state should be brought to FESCo for review. Please update the state of this bug to "ON_QA" if it is already 100% completed. Please let me know in case you have any trouble with the implementation and the Change needs any help or review.

Thanks, Jan

Comment 11 Fedora Update System 2018-03-06 12:44:00 UTC
crypto-policies-20180306-1.gitaea6928.fc28 has been submitted as an update to Fedora 28.

Comment 12 Nikos Mavrogiannopoulos 2018-03-07 08:44:08 UTC
Current status: 
 Due to regressions seen in connecting to (1) internal/intranet web sites, (2) SSL VPN servers, I've backed off some of the original plan and modified the plan description [0] to the implemented plan.

Original plan:
* Keep only TLS 1.2 (and TLS 1.3 when available) as enabled protocols and move the TLS 1.x, x<=1 to legacy level.
* Require finite field parameters (RSA, Diffie-Hellman) of 2048 and more in the default settings
* Disable DSA by default

Fallback (current plan):
* Disable DSA by default
* Require RSA certificates of 2048 bits and more in the default settings (Diffie-Hellman remains >= 1024)

The items in the original plan that were not implemented are to be postponed to a later time. I also renamed the change to "Strong crypto settings: phase 1" to reflect that.

The fallback plan requires the updates in [1] to be merged.


Comment 13 Fedora Update System 2018-03-08 15:25:54 UTC
crypto-policies-20180306-1.gitaea6928.fc28, openssh-7.6p1-7.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report.
See for
instructions on how to install test updates.
You can provide feedback for this update here:

Comment 14 Fedora Update System 2018-03-30 12:42:53 UTC
crypto-policies-20180306-1.gitaea6928.fc28, openssh-7.6p1-7.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.

Note You need to log in before you can comment on or make changes to this bug.