WIP: DO NOT REVIEW Cache SslStream certificate hashes#130615
Draft
artl93 wants to merge 1 commit into
Draft
Conversation
Avoid recomputing and reallocating the SHA-512 certificate hash for each TLS credential cache lookup when a certificate context is reused. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: e9b4cc84-3f86-481e-9c92-03023269817c
Contributor
|
Tagging subscribers to this area: @dotnet/ncl, @bartonjs, @vcsjones |
Contributor
There was a problem hiding this comment.
Pull request overview
This PR introduces an internal SHA-512 certificate-hash cache on SslStreamCertificateContext and uses it during credential-cache probes in SslStream to avoid repeated X509Certificate.GetCertHash(HashAlgorithmName.SHA512) work when the same reusable context is used across connections.
Changes:
- Add
SslStreamCertificateContext.GetCertificateHash()which caches/publishes{cert-handle, hash}usingVolatilefor safe cross-thread reuse. - Update
SslStream.Protocolcredential acquisition paths to prefer the cached hash when the selected certificate is the context’s target certificate. - Add functional tests for concurrent authentication using a reused certificate context and for hash caching behavior (via reflection).
Show a summary per file
| File | Description |
|---|---|
| src/libraries/System.Net.Security/tests/FunctionalTests/SslStreamCredentialCacheTest.cs | Adds a concurrent multi-connection theory that reuses SslStreamCertificateContext (optionally with ALPN and mutual TLS). |
| src/libraries/System.Net.Security/tests/FunctionalTests/SslStreamCertificateContextTests.cs | Adds a reflection-based test for GetCertificateHash() reuse and disposed-certificate behavior. |
| src/libraries/System.Net.Security/src/System/Net/Security/SslStreamCertificateContext.cs | Implements cached certificate hash storage on the reusable context. |
| src/libraries/System.Net.Security/src/System/Net/Security/SslStream.Protocol.cs | Uses the cached hash for credential-cache keying instead of re-hashing each probe. |
Copilot's findings
- Files reviewed: 4/4 changed files
- Comments generated: 2
Comment on lines
+21
to
+30
| public static IEnumerable<object[]> CredentialReuseData() | ||
| { | ||
| foreach (SslProtocols protocol in SslProtocolSupport.EnumerateSupportedProtocols(SslProtocols.Tls12 | SslProtocols.Tls13, true)) | ||
| { | ||
| yield return new object[] { protocol, false, false }; | ||
| yield return new object[] { protocol, true, false }; | ||
| yield return new object[] { protocol, true, true }; | ||
| } | ||
| } | ||
|
|
|
|
||
| TargetInvocationException exception = Assert.Throws<TargetInvocationException>( | ||
| () => getCertificateHash.Invoke(context, null)); | ||
| Assert.IsAssignableFrom<CryptographicException>(exception.InnerException); |
Member
Author
|
Still WIP — DO NOT REVIEW. The exact-parent publication pass is complete, but this draft is intentionally not ready for review.
Frozen harness identity:
Raw artifact publication and CI review remain outstanding. Please do not review yet. Note This WIP status comment was generated with GitHub Copilot. |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
I am running an experiment - full analysis to follow. Contact @artl93
This draft investigates repeated SHA-512 certificate digest work during
SslStreamcredential-cache probes when anSslStreamCertificateContextis reused.Exact-parent component evidence (local Debug build only)
Local environment: Apple M5 Pro (18 logical CPUs), macOS 26.5.2 arm64, repo-built .NET 11 Debug libraries testhost. Parent
7aa830a03599a8255c2c4abf2947afc5b346cc6f; candidated1518851d013212171c5255c85698c954296657c.A frozen external harness invokes the real private server method
SslStream.AcquireServerCredentials(ref byte[]?)after configuring reusable server authentication options. It does not merely compare direct and cached helper calls. Each revision used an isolated immutable testhost. The run alternated parent/candidate order across 8 process launches, with 1,000,000 warmup probes and 7 trials of 1,000,000 probes per launch (56 measured trials/revision).These magnitudes are not shipping/Release performance numbers. Attempts to create a coherent Release-libraries testhost in this checkout are currently blocked by pre-existing CoreLib/LibraryImport generation failures; the failed commands/logs are retained. The table is evidence for the repeated-work mechanism and Debug component impact only.
On Apple,
AcquireServerCredentialsreturnedcachedCreds == falsein all trials. This platform path has a cheap/null PAL credential handle at this stage; native TLS security-context construction occurs later during the handshake. The timed method still performs certificate selection, hash acquisition, credential-cache key lookup, and that PAL call. The result should not be read as native credential-construction time. The client credential path is changed too, but this canonical benchmark measures only the server path.A separate baseline trace attributed 19.29% inclusive samples to
X509Certificate.GetCertHash -> HashData -> Interop.AppleCrypto.DigestOneShotin an isolated process that also included certificate/setup work. That percentage validates stack attribution only; it is not the hash share ofAcquireServerCredentialsand is not used to derive the 10.71x table.The frozen harness is currently external to this PR. It self-identifies revision, source/binary hashes, loaded
System.Net.Security.dllhash, runtime/OS, full command, warmups, iterations, and trials. Canonical identities:37132680bc488327349e625a36cad7c000d308181390f2f89141e6ede6dc6deb6137092338f45c133d5dfc03c02945637914f79cf7c6c3bb7b0f353834e4bea9System.Net.Security.dll:3b3a00a5ac8e52d098151eed0456723cd9527f61ade48313fd62f4245379d123System.Net.Security.dll:2f4ee6e2d5c3cccf4a9fba3091fabb0226ef815766dd6646fde5046e83232450Raw harness/log publication is still pending; this remains WIP.
Why cache on
SslStreamCertificateContextThe credential-cache key includes a SHA-512 digest of the selected certificate. A reusable certificate context represents the same target certificate across many connections, but the previous code recomputed that digest and allocated a fresh array on every client/server credential probe.
The change lazily stores an immutable
{ certificate handle, hash }cache entry on the context and publishes it atomically. Reuse requires the current native certificate handle to match. On a miss, the digest is computed and published only if the handle is unchanged before/after hashing. Disposal/reset changes the handle and preserves the existingCryptographicExceptionbehavior instead of returning stale data. The byte array remains internal and is never mutated. No public API changes.This is managed cross-platform code used above Schannel, OpenSSL, Apple TLS, and Android. Local execution covers Apple only; all configured System.Net.Security target frameworks compile in the validated Debug build, and runtime behavior on other platforms depends on CI/platform validation.
Supporting handshake evidence — explicitly not a performance claim
Four interleaved launches per revision exercised TLS 1.2 with reused/fresh contexts, ALPN, mTLS, resumption enabled/disabled, and concurrency 1/16. All successful runs negotiated TLS 1.2; ALPN scenarios negotiated
h2. The internal resumed-session flag was observable and recorded zero resumed sessions on both client and server, even whenAllowTlsResume=true. TLS 1.3 timed out identically for parent/candidate on this Apple testhost.Whole-handshake elapsed deltas ranged from -2.7% to +3.1%, and CPU deltas changed sign across scenarios. These results are noisy and do not establish an HTTPS or TLS-handshake speedup. No request-throughput claim is made. The supported local claim is limited to the Debug server credential-probe component.
Validation
Targeted coverage includes atomic concurrent publication through 16 simultaneous reused-context connections, protocol negotiation, ALPN, mTLS/client certificates, certificate validation, encrypted data transfer, cached hash identity, and disposed-certificate invalidation.
Rejected variants
Context-level caching is smaller, aligns lifetime with the reusable certificate context, and avoids repeated digest work and per-probe array allocation.
Note
This draft PR description was generated with GitHub Copilot. The PR intentionally remains WIP and should not be reviewed yet.