1809872 - DTLS1.3 RFC types mismatch

Status: RESOLVED FIXED

(NSS :: Libraries, defect, P4)

Description

[Anna Weine]

We observed that the types used in the DTLS1.3:

• sslSequenceNumber:
  https://searchfox.org/mozilla-central/source/security/nss/lib/ssl/sslspec.h#29 vs RFC 9147 Section 4 The DTLS Record Layer
  struct { uint64 epoch; uint64 sequence_number; } RecordNumber;

• epoch:
  https://searchfox.org/mozilla-central/source/security/nss/lib/ssl/sslspec.h#30 vs
  vs RFC 9147 6.1. Epoch Values :
  Epoch values (4 to 2^64-1)

Comment 1

[Anna Weine]

Found during the interoperability testing with WolfSSL: https://bugzilla.mozilla.org/show_bug.cgi?id=1809196#c3 and https://bugzilla.mozilla.org/show_bug.cgi?id=1809196#c4.

Comment 2

[Anna Weine]

The comment https://bugzilla.mozilla.org/show_bug.cgi?id=1809196#c4 suggest not to modify the existing structures, but to adapt the ACK message.

Comment 3

[Anna Weine]

Attachment: Bug 1809872 - Modification the DTLS1.3 Message: Sending epoch and seqNum separately as two uint64

Comment 4

[Anna Weine]

Copy paste from the interoperability bug:

Related problem. The dtls13_HandleAck function processes incorrectly the acknowledgements. Instead of seeing them as (epoch, seq), it parses it as (seq). That's why the acknowledgement of the messages does not work.

Quick fix:

rv = ssl3_ConsumeHandshakeNumber64(ss, &epoch, 8, &b, &l);
rv = ssl3_ConsumeHandshakeNumber64(ss, &seq, 8, &b, &l);
seq = dtls_CombineSequenceNumber(epoch, seq);

Comment 5

[Anna Weine]

This patch also requires the same modification in the testing facilities (CheckAcks function). I needed to update the expected size of the ACK messages.

https://phabricator.services.mozilla.com/D170598#change-35FPTx1FSoxv

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

There is an r+ patch which didn't land and no activity in this bug for 2 weeks.
:nkulatova, could you have a look please?
If you still have some work to do, you can add an action "Plan Changes" in Phabricator.
For more information, please visit BugBot documentation.

Comment 7

[Anna Weine]

Attachment: Bug 1809872 - DTLS test TlsAgentDgramTestClient.AckWithNonEvenLengthwas failing due to not establishing the correct error code

Comment 8

[Anna Weine]

https://hg.mozilla.org/projects/nss/rev/38073deff026832986213d9e58b04f4a898759fc