tree f4aa0779ea23ff3895226cf2b3f859e0b3e5062a
parent 5d29dda5306b70f0eb702d7a297c56a052176a98
author Michael Schaffner <msf@google.com> 1622850410 -0700
committer Michael Schaffner <msf@google.com> 1623952808 -0700

[alert_handler] Duplicate LFSR counter and update EDN reseeding logic

This duplicates the timer counters inside the LFSR timer to harden this
module against FI attacks. In case the LFSRs or counters do not agree,
the ping fail alerts are continuously asserted.

This also updates the entropy hookup to EDN - although this will have to
be finalized when the reverse ping mechanism for escalation receivers is
added (the reseeding needs to be properly synchronized with the timeout
counters inside the escalation receivers since this could otherwise lead
to spurious escalation action triggers).

See also #2049

Signed-off-by: Michael Schaffner <msf@google.com>