Improve MSSQL JS fingerprint via TDS prelogin

[Mzack9999]

Summary

• Add native TDS prelogin FingerprintMssql; wire IsMssql to the same probe
• Integration template + unit/integration tests
• Closes Add/Improve Fingerprint data in Mssql Module #4864

Summary by CodeRabbit

• New Features
  • Added MSSQL pre-login fingerprinting to capture protocol version/build, encryption settings, and server capability indicators.
  • Added a new integration test case for the MSSQL fingerprint template.
• Bug Fixes
  • Updated MSSQL detection to rely on the fingerprint probe for more consistent identification, including correct handling of non-MSSQL replies as a negative match.
• Tests
  • Added unit tests for pre-login parsing/validation and detection behavior.
  • Added integration-style tests using an in-process TCP mock server and template execution.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: d114cd0d-76e6-4667-a609-d997bc9560c3

📥 Commits

Reviewing files that changed from the base of the PR and between ba31a68 and af049c2.

📒 Files selected for processing (1)

• internal/tests/integration/javascript_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• internal/tests/integration/javascript_test.go

---

Walkthrough

Adds MSSQL TDS pre-login fingerprinting with parsed server metadata, memoized execution, MSSQL detection reuse, and JavaScript integration tests backed by a localhost mock listener.

Changes

MSSQL fingerprinting

Layer / File(s)	Summary
TDS pre-login parsing and validation pkg/js/libs/mssql/fingerprint.go, pkg/js/libs/mssql/fingerprint_test.go	Defines MSSQLInfo, validates and parses TDS pre-login responses, maps encryption modes, and tests parsed fields and invalid packet types.
Fingerprint execution and detection reuse pkg/js/libs/mssql/fingerprint.go, pkg/js/libs/mssql/memo.fingerprint.go, pkg/js/libs/mssql/mssql.go, pkg/js/libs/mssql/fingerprint_test.go	Performs allowlisted TCP fingerprinting, memoizes results, and uses fingerprint outcomes in IsMssql.
JavaScript template integration test internal/tests/integration/javascript_mssql_test.go, internal/tests/integration/javascript_test.go	Registers the MSSQL JavaScript testcase and validates one result against a mock pre-login listener.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant JavaScriptTemplate
  participant MSSQLClient
  participant MockMSSQLServer
  JavaScriptTemplate->>MSSQLClient: Request MSSQL fingerprint
  MSSQLClient->>MockMSSQLServer: Send TDS pre-login request
  MockMSSQLServer-->>MSSQLClient: Return crafted pre-login response
  MSSQLClient-->>JavaScriptTemplate: Return parsed MSSQLInfo

Loading

Poem

I’m a rabbit with packets to parse,
Through tunnel and carrot-lit wire I race.
TDS crumbs reveal version and mode,
Cached hops lighten the network road.
One mock server answers—what a fine trace!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is concise and accurately reflects the main change: improving MSSQL fingerprinting via TDS prelogin.
Linked Issues check	✅ Passed	The PR adds MSSQL prelogin fingerprinting with version/config parsing and updates IsMssql to use the new probe as requested.
Out of Scope Changes check	✅ Passed	The new tests, memoized wrapper, and integration template all support the MSSQL fingerprinting work and appear in scope.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch 4864-mssql-fingerprint

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@pkg/js/libs/mssql/fingerprint.go`:
- Around line 100-159: Update fingerprintMssql and its IsMssql caller to
distinguish parsePreloginResponse failures or missing MSSQL version tokens from
transport and permission errors: return a non-MSSQL result as (false, nil) for
unparseable/non-MSSQL TDS responses, while continuing to propagate dial,
allowlist, initialization, read, write, and other probe failures as errors.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: fdba497a-e6a5-4a67-9e84-768b1ed03ceb

📥 Commits

Reviewing files that changed from the base of the PR and between bcf2089 and 6787cdb.

⛔ Files ignored due to path filters (3)

• internal/tests/integration/testdata/protocols/javascript/mssql-fingerprint.yaml is excluded by !**/*.yaml
• pkg/js/generated/go/libmssql/mssql.go is excluded by !**/generated/**
• pkg/js/generated/ts/mssql.ts is excluded by !**/generated/**

📒 Files selected for processing (6)

• internal/tests/integration/javascript_mssql_test.go
• internal/tests/integration/javascript_test.go
• pkg/js/libs/mssql/fingerprint.go
• pkg/js/libs/mssql/fingerprint_test.go
• pkg/js/libs/mssql/memo.fingerprint.go
• pkg/js/libs/mssql/mssql.go

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@pkg/js/libs/mssql/fingerprint_test.go`:
- Around line 68-73: Update TestFingerprintMarksInvalidPacketAsNotMssql to
exercise fingerprintMssql with the invalid packet and assert it returns a
non-MSSQL result while preserving the expected error behavior. Do not manually
wrap the parser error with errNotMssql, since that only tests the test’s own
fmt.Errorf call; if testing isMssqlResult directly instead, pass the wrapped
value into it and assert (false, nil).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 7a5f1d7b-24d3-4806-8afd-8d35fb46a6b7

📥 Commits

Reviewing files that changed from the base of the PR and between 6787cdb and 604cffc.

📒 Files selected for processing (3)

• pkg/js/libs/mssql/fingerprint.go
• pkg/js/libs/mssql/fingerprint_test.go
• pkg/js/libs/mssql/mssql.go

🚧 Files skipped from review as they are similar to previous changes (2)

• pkg/js/libs/mssql/mssql.go
• pkg/js/libs/mssql/fingerprint.go