[SergeyMenshykh]

Motivation and Context

Improve consistency of the built-in OpenAPI HTTP client while preserving request identity and existing customization points.

Description

Refine connection handling and internal validation-result propagation. Preserve caller-supplied clients and existing redirect behavior. Add regression coverage for connection selection, pooling, and HTTPS behavior.

[Copilot]

🟡 Changes recommended

The new owning HTTP clients lack a disposal path, potentially retaining connection pools and sockets.

1 open finding

• Prevent leaked HttpClient handlers when generated plugins are undisposed · New

What changed in this PR

Improves OpenAPI SSRF protection by binding validated DNS addresses to outgoing connections while preserving host identity and custom clients.

Changes:

• Propagates validated DNS addresses to HTTP requests.
• Adds separate pinned and unpinned connection pools.
• Adds connection, TLS, pooling, and client-preservation tests.

File	Description
PublicNetworkAddressValidator.cs	Returns validated DNS addresses.
ServerUrlValidatorTests.cs	Verifies validation results.
OpenApiHttpClientProviderTests.cs	Tests pinning, pooling, TLS, and custom clients.
ServerUrlValidator.cs	Propagates validated addresses.
RestApiOperationRunner.cs	Attaches addresses to requests.
OpenApiKernelPluginFactory.cs	Uses the new default HTTP client.
OpenApiHttpClientProvider.cs	Implements pinned connection handling.
OpenApiFunctionExecutionParameters.cs	Documents pinning limitations.

🧠 Review effort: Balanced

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[semantic-kernel-automation]

MAF Automated Review — Iteration 1

Result: Findings reported
Scope: full PR (1 commit(s)): 1ce41a37edc5
Model: gpt-5.6-sol

Overview

The PR carries validated DNS results into the built-in .NET client, separates pinned and unchecked socket pools, preserves the HTTP/TLS hostname, and retains redirect and certificate checks. The regression tests cover direct exact-address routing, pool separation, SNI, and validator propagation. Three Medium risks remain: the newly owned handlers lack a deterministic lifetime, sequential address attempts can prevent fallback to a healthy endpoint, and manifest-based imports lose document-session cookies when they create a second default client for operations.

Reviewed the supplied pull-request change set across correctness, security/reliability, architecture, and failure behavior.
3 verified findings remained after source verification (3 medium) across 2 files. Details are attached to the affected lines below.

Affected areas: dotnet/src/Functions/Functions.OpenApi/OpenApiHttpClientProvider.cs, dotnet/src/Functions/Functions.OpenApi/OpenApiKernelPluginFactory.cs