openssl/openssl

[Padlock] AES-256 does not work for QUIC

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#24,879 opened on Jul 14, 2024

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help wantedtriaged: bug

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Description

Issue #20073, take two.

TLS_AES_256_GCM_SHA384 does not work with VIA engine padlock when using curl with --http3-only (QUIC) option: curl hangs on connection attempt and does not accept the reply packets sent from the server, without any error.

Tested on x86 VIA Eden Esther 1 GHz and on x86_64 VIA Eden X2 U4200, both x86 and x86_64 builds. TLS_AES_128_GCM_SHA256 and TLS_CHACHA20_POLY1305_SHA256 work fine. Running curl with rebuilt openssl with no-hw-padlock solves the issue for TLS_AES_256_GCM_SHA384.

I could not reproduce the issue with regular TLS connection using curl (not QUIC), as well as with demos/http3 (with the patch to select SSL_CTX_set_ciphersuites(ctx, "TLS_AES_256_GCM_SHA384")).

I don't know how to debug this issue further. Tested with:

  • OpenSSL quictls 3.1.5
  • OpenSSL 3.3.0
  • OpenSSL 3.3.1

curl issue: https://github.com/curl/curl/issues/14180

@bernd-edlinger, I can provide VIA X2 U4200 machine to debug this time, it has more RAM and dual-core x86_64 CPU.

Contributor guide

Research direction
Investigate the VIA Padlock engine implementation in openssl/crypto/engine/eng padlock.c. Compare the handling of AES 256 GCM with AES 128 GCM in the context of QUIC connections. The reporter has offered access to VIA hardware for debugging. Check if the issue is related to the QUIC specific code paths in ssl/statem/statem quic.c or similar.
Tech stack
c
Domain
security
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
5
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Needs maintainer response
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
C programmingOpenSSL internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
10