[Engineering task] Support forwarding MSAL client metadata headers through IMDS (classic) to ESTS

[gladjohn]

MSAL client type

Confidential

Problem Statement

Task type

Development

Description

Title

Support forwarding MSAL client metadata headers through IMDS to ESTS

Description

Enable MSAL to send client metadata headers to IMDS on Managed Identity token requests, along with Metadata: true. IMDS should accept these headers and forward the corresponding values on the downstream ESTS token request.

Headers

• Metadata: true
• x-client-sku
• x-client-ver
• client-request-id

Example

• x-client-sku: MSI.IMDS.Prod-AzureSDK
• x-client-ver: 10.2.1456-2019-08-01-1.11.3
• client-request-id: 11111111-2222-3333-4444-555555555555

Expected flow

• MSAL → IMDS: sends Metadata: true, x-client-sku, x-client-ver, and client-request-id
• IMDS → ESTS: forwards the corresponding client metadata headers

Acceptance Criteria

• IMDS accepts x-client-sku, x-client-ver, and client-request-id from MSAL requests
• IMDS preserves Metadata: true handling as it does today
• IMDS forwards the client metadata headers on the ESTS token request
• Header forwarding is validated with a test or trace showing the end-to-end flow

Solution

No response

Proposed solution

No response