25-sidechan-6up.pdf-Computer Science 202...
25-sidechan-6up.pdf-Computer Science 2021 Side channels and
Showing 1 out of 6
25-sidechan-6up.pdf-Computer Science 2021 Side cha...
25-sidechan-6up.pdf-Computer Science 2021 Side channels and
25-sidechan-6up.pdf-Computer Scienc...
25-sidechan-6up.pdf-Computer Science 2021 Side channels and
Page 1
1
1
Computer Science 2021
Side channels and transient execution
CSci 2021: Machine Architecture and Organization
December 10th, 2018
Stephen McCamant
2
Computer Science 2021
Today
Side and covert channels
Transient execution
Transient execution and kernel isolation: Meltdown
Transient execution and software checks: Spectre
Fixes, lessons learned, and the future
3
Computer Science 2021
Information protection
Most security goals relate to one of two properties
1.
Keep adversaries from taking control
2.
Protect sensitive (secret private, confidential, etc.)
information from being revealed
Buffer overflows were most commonly a problem for #1
Though read buffer overflows can be bad for #2, like “Heartbleed”
Each goal eventually depends on the other
An adversary with control can send access information directly
Control is protected by secrets like passwords
Today is about security problems of the #2 variety
4
Computer Science 2021
Side channels
A
side channel
is an unexpected way in which a system
reveals information, different from how information is
intentionally output
Analog side channels are mediated by the physical world
outside the machine, e.g.:
Sound of the hard-disk running
Power usage
Digital side channels reveal information while staying
inside the computer abstraction, e.g.:
You can’t read a file, but the error message reveals that it exists
Running time of an operation depends on what else is running
5
Computer Science 2021
Side channels vs. covert channels
In a side channel, information is revealed from an
unsuspecting victim.
Sound of many people erasing indicates that an exam question is
difficult
In a covert channel, the source of the information is
working together with the receiver to transmit it when
they shouldn’t.
Cough once if the answer is “true”, twice if it is “false”
Often the channel itself is the same, it just differs how
you use it
And not everyone is careful about this distinction
6
Computer Science 2021
“Architectural”
Recall that the instruction-set architecture is an
abstraction that hides details
Above the line: programmer visible state
Below the line, pipelining, caches, etc.
Another form of this terminology distinction you will hear
is:
“Architectural” means the above-the-line view
“Micro-architectural” means the below-the-line view
If information is available only because of a micro-
architectural behavior, that’s likely a side channel


Ace your assessments! Get Better Grades
Browse thousands of Study Materials & Solutions from your Favorite Schools
University of Minnesota-T...
University_of_Minnesota-Twin_Cities
School:
Machine_Architecture
Course:
Great resource for chem class. Had all the past labs and assignments
Leland P.
Santa Clara University
Introducing Study Plan
Using AI Tools to Help you understand and remember your course concepts better and faster than any other resource.
Find the best videos to learn every concept in that course from Youtube and Tiktok without searching.
Save All Relavent Videos & Materials and access anytime and anywhere
Prepare Smart and Guarantee better grades

Students also viewed documents