Seminars

View all Seminars  |  Download ICal for this event

SafeBet: A Simple, Secure and Fast Solution for Spectre and Meltdown

Series: Department Seminar

Speaker: Prof. Mithuna Thottethodi Purdue University

Date/Time: Jul 04 15:00:00

Location: CSA Seminar Hall (Room No. 254, First Floor)

Abstract:
Spectre and Meltdown attacks exploit microprocessor speculative
execution to read and transmit forbidden data outside the attacker's
trust domain and sandbox. Recent hardware schemes allow
potentially-unsafe speculative accesses but prevent the secret's
transmission by delaying all or many of the access-dependent
instructions, even in the predominantly-common, no-attack case, which
incurs performance loss and hardware complexity. Instead, we propose
SafeBet which allows only, and in the common case does not delay most,
safe accesses. We make the key observation that speculatively accessing
a location is safe if the location has been accessed previously
non-speculatively by the same trust domain (i.e., the location is
within the domain's sandbox); and potentially unsafe, otherwise. We call
the location as destination and the code memory region of the trust
domain as the source. SafeBet employs the Speculative Memory Access
Control Table (SMACT) to track non-speculative source
address-destination address pairs. Disallowed accesses wait until
reaching commit to trigger well-known replay without any intrusive
hardware changes. SafeBet prevents all variants of Spectre and
Meltdown except Lazy-FP-restore, based on any current or future side
channel while using only simple, table-based access control and cache
miss replay with virtually no change to the pipeline. Software
simulations show that SafeBet uses 8.3 KB per core for the tables to
perform within 6% on average (63% at worst) of the unsafe baseline
behind which NDA-restrictive, a previous scheme of security and
hardware complexity comparable to SafeBet's, lags by 83% on average.

This work has been done in collaboration with Prof. T. N. Vijaykumar
and our graduate students Conor Green and Cole Nelson.

Speaker Bio:
Mithuna Thottethodi is Professor of Elmore Family School of Electrical and Computer Engineering at Purdue University. His research interests include computer architecture, security, ML accelerators, datacenter-scale systems and interconnection networks.

Host Faculty: Arkaprava Basu