NetBSD Problem Report #57427

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Date: Mon, 22 May 2023 14:19:03 +0000 (UTC)
From: campbell+netbsd@mumble.net
Reply-To: campbell+netbsd@mumble.net
To: gnats-bugs@NetBSD.org
Subject: mvxpsec(4) is vulnerable to cache-timing attacks on table-based AES key schedule
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>Number:         57427
>Category:       kern
>Synopsis:       mvxpsec(4) is vulnerable to cache-timing attacks on table-based AES key schedule
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 22 14:20:01 +0000 2023
>Originator:     Taylor R Campbell
>Release:        current
>Organization:
The NetAES Foundatoin
>Environment:
>Description:
The mv_aes_enckey and mv_aes_deckey functions compute the AES key schedule using a table-driven S-box computation, which is vulnerable to cache-timing side channel attacks.

These functions should be changed to call br_aes_ct_keysched_stdenc and br_aes_ct_keysched_stddec instead.

This requires testing to verify that mv_aes_enckey/deckey are actually computing the standard AES key schedule; if they actually do a variant key schedule, well, someone has to write some bitsliced or vector-permuted code or something to compute the variant.
>How-To-Repeat:
code inspection
>Fix:
Yes, please!

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