net/http: reject control characters in Response.Write

[DhruvilK7]

Summary

Fixes #78774.

Problem

Response.Write did not validate the Status field for control characters before writing it to the wire. A crafted Status value containing \r\n could inject arbitrary headers into the HTTP response, enabling response splitting attacks.

Solution

Add a stringContainsCTLByte check on the status text in Response.Write, mirroring the existing validation for Request.URL in Request.Write. Return an error if control characters are detected.

Changes

• src/net/http/response.go: 4 lines added — CTL byte validation before writing the status line
• src/net/http/responsewrite_test.go: Convert respWriteTest entries to named fields and add WantError field to the test struct for extensible error-case testing; add test case for control character rejection

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Patch Set 1:

(1 comment)

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