[AmirMS (AmelBawa-msft)]

📖 Description

Prevent automatic redirects from forwarding sensitive download headers to another origin.

🔗 References

🔍 Validation

✅ Checklist

• Signed the Contributor License Agreement
• Linked to an issue
• Added a release note fragment (if applicable)
• Updated documentation (if applicable)
• Added or updated tests (or noted why not applicable)
• Updated Copilot instructions (if build, architecture, or conventions changed)

🤖 AI Assistance

• AI assistance was used and has been disclosed in this PR
• No AI assistance was used

📋 Issue Type

• Bug fix
• Feature
• Task

Microsoft Reviewers: Open in CodeFlow

[Copilot]

🟡 Changes recommended

Authenticated installer downloads switch directly to WinINet, bypassing Delivery Optimization’s cost and cellular restrictions that must remain enforced.

1 open issue

• Authenticated fallback bypasses DO cost and cellular policies · New

What changed in this PR

This PR hardens WinGet downloads by controlling authenticated redirects and stripping sensitive headers when the destination origin changes.

Changes:

• Adds per-hop redirect handling, HTTPS downgrade protection, and a redirect limit.
• Routes authenticated installer downloads through WinINet rather than Delivery Optimization.
• Adds redirect-policy and transport tests, localhost test endpoints, and a release note.

File	Description
src/​LocalhostWebServer/​Startup.cs	Adds loopback-only redirect and header-check endpoints.
src/​AppInstallerCommonCore/​Public/​AppInstallerDownloader.h	Documents sensitive-header redirect behavior.
src/​AppInstallerCommonCore/​Downloader.cpp	Implements redirect safeguards and authenticated-download routing.
src/​AppInstallerCommonCore/​DODownloader.cpp	Adds a Delivery Optimization test override.
src/​AppInstallerCLITests/​TestHooks.h	Exposes redirect-policy and downloader test hooks.
src/​AppInstallerCLITests/​Downloader.cpp	Adds policy, transport, and downloader-routing coverage.
doc/​release-notes/​1.31/​authenticated-download-redirects.md	Documents the sensitive-header protection.

_{Review effort: Balanced}