Add early rejection from RestHandler for unauthorized requests

[cwperks]

Description

Previously unauthorized requests were fully processed and rejected once they reached the RestHandler. This allocations more memory and resources for these requests that might not be useful if they are already detected as unauthorized. Using the headerVerifer and decompressor customization from [1], perform an early authorization check when only the headers are available, save an 'early response' for transmission and do not perform the decompression on the request to speed up closing out the connection.

graph TD

    oA["Receive Request Headers<br>(Orginal)"] --> oB[Decompress Request]
    oB --> oC[RestHandler]
       oC --> osrf[Intercept Request]
    subgraph sp[Security Plugin]
       osrf --> oD[Check Authorization]
       oD --> oE{Authorized?}
       oE -->|Yes| oF[Process and Respond]
       oE -->|No| oG[Reject Request]
   end
   oF --> oH[Forward to Request Handler]



    H["Receive Request Headers<br>(Updated)"] --> I[HeaderVerifier]
    subgraph nsp[Security Plugin]
       I --> J{Authorized?}
       J -->|Yes| K[Decompress Request]
       J -->|No| N[Save Early Response]
    end
    K --> L[RestHandler]
    N --> L
    L --> M[Intercept Request]
    subgraph n2sp[Security Plugin]
       M --> n2D["Check Authorization<br>(Cached)"]
       n2D --> nE{Authorized?}
       nE -->|Yes| nF[Process and Respond]
       nE -->|No| nG[Reject Request]
   end
   nF --> nH[Forward to Request Handler]

class oA,oB old;
class H,I,K,N,n2D new;
classDef old fill:#f9d0c4,stroke:#f28b82;
classDef new fill:#cfe8fc,stroke:#68a9ef;

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Issues Resolved

• Resolves [Feature] Improve compressed request handling OpenSearch#10260
• [1] Related Allow customization of netty channel handles before and during decompression OpenSearch#10261

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[DarshitChanpura]

LGTM. Left some non-blocking questions.

[RyanL1997]

Approving, since I had some context from #3430. I just left a minor comment for my knowledge, and we can address that separately.

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/security/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/security/backport-2.x
# Create a new branch
git switch --create backport/backport-3418-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 6b0b682da2cb0feabb54489731472a05af1d4b1b
# Push it to GitHub
git push --set-upstream origin backport/backport-3418-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/security/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-3418-to-2.x.

[opensearch-trigger-bot]

The backport to 2.11 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/security/backport-2.11 2.11
# Navigate to the new working tree
pushd ../.worktrees/security/backport-2.11
# Create a new branch
git switch --create backport/backport-3418-to-2.11
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 6b0b682da2cb0feabb54489731472a05af1d4b1b
# Push it to GitHub
git push --set-upstream origin backport/backport-3418-to-2.11
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/security/backport-2.11

Then, create a pull request where the base branch is 2.11 and the compare/head branch is backport/backport-3418-to-2.11.

[peternied]

Working on the 2.11 backport...