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refactor: final surgical removal of hardcoded provider defaults and insecure HMAC fallback

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Amr Gharbeia
2026-04-12 19:42:20 -04:00
parent bfe46003d1
commit 10a500c480
4 changed files with 37 additions and 33 deletions
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32
literate/protocol.org
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@@ -66,13 +66,14 @@ The ~frame-message~ function prepares an outgoing Lisp string for transmission.
(let ((len (length msg-string))
(enforce-hmac (uiop:getenv "HARNESS_PROTOCOL_ENFORCE_HMAC")))
(if (and enforce-hmac (string-equal enforce-hmac "true"))
(let* ((secret (or (uiop:getenv "HARNESS_PROTOCOL_HMAC_SECRET") "default-insecure-key"))
(key (ironclad:ascii-string-to-byte-array secret))
(hmac (ironclad:make-mac :hmac key :sha256))
(payload-bytes (ironclad:ascii-string-to-byte-array msg-string)))
(ironclad:update-mac hmac payload-bytes)
(let ((signature (ironclad:byte-array-to-hex-string (ironclad:produce-mac hmac))))
(format nil "~(~6,'0x~)~a~a" len signature msg-string)))
(let ((secret (uiop:getenv "HARNESS_PROTOCOL_HMAC_SECRET")))
(unless secret (error "HARNESS_PROTOCOL_HMAC_SECRET is required when security is enabled."))
(let* ((key (ironclad:ascii-string-to-byte-array secret))
(hmac (ironclad:make-mac :hmac key :sha256))
(payload-bytes (ironclad:ascii-string-to-byte-array msg-string)))
(ironclad:update-mac hmac payload-bytes)
(let ((signature (ironclad:byte-array-to-hex-string (ironclad:produce-mac hmac))))
(format nil "~(~6,'0x~)~a~a" len signature msg-string))))
(format nil "~(~6,'0x~)~a" len msg-string))))
#+end_src
@@ -100,14 +101,15 @@ Parsing is the high-security inverse of framing. This function acts as the final
(error "Message length mismatch. Expected ~a, got ~a" expected-len (length actual-msg)))
(when use-hmac
(let* ((secret (or (uiop:getenv "HARNESS_PROTOCOL_HMAC_SECRET") "default-insecure-key"))
(key (ironclad:ascii-string-to-byte-array secret))
(hmac (ironclad:make-mac :hmac key :sha256))
(payload-bytes (ironclad:ascii-string-to-byte-array actual-msg)))
(ironclad:update-mac hmac payload-bytes)
(let ((expected-signature (ironclad:byte-array-to-hex-string (ironclad:produce-mac hmac))))
(unless (string-equal signature expected-signature)
(error "Harness Protocol Integrity Failure: HMAC mismatch")))))
(let ((secret (uiop:getenv "HARNESS_PROTOCOL_HMAC_SECRET")))
(unless secret (error "HARNESS_PROTOCOL_HMAC_SECRET is required when security is enabled."))
(let* ((key (ironclad:ascii-string-to-byte-array secret))
(hmac (ironclad:make-mac :hmac key :sha256))
(payload-bytes (ironclad:ascii-string-to-byte-array actual-msg)))
(ironclad:update-mac hmac payload-bytes)
(let ((expected-signature (ironclad:byte-array-to-hex-string (ironclad:produce-mac hmac))))
(unless (string-equal signature expected-signature)
(error "Harness Protocol Integrity Failure: HMAC mismatch"))))))
;; SECURITY: Disable the reader's ability to execute code during parsing
(let ((*read-eval* nil))