From 05e5bdd488a309b70ca140fc620ad48023befa24 Mon Sep 17 00:00:00 2001 From: "F. Jason Park" Date: Mon, 19 Sep 2022 21:28:52 -0700 Subject: [PATCH 2/5] Add GS2 authorization to sasl-scram-rfc * lisp/net/sasl-scram-rfc.el (sasl-scram-gs2-header-function, sasl-scram-construct-gs2-header): Add new variable and default function for determining a SCRAM GSS-API message header. `defcustom' not used because library doesn't define any others. (sasl-scram-client-first-message): Use gs2-header function. (sasl-scram--client-final-message): Use dedicated gs2-header function. Also remove whitespace when base64-encoding, as per RFC 5802. Bug#57956. --- lisp/net/sasl-scram-rfc.el | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/lisp/net/sasl-scram-rfc.el b/lisp/net/sasl-scram-rfc.el index ee52ed6e07..f7a2e42541 100644 --- a/lisp/net/sasl-scram-rfc.el +++ b/lisp/net/sasl-scram-rfc.el @@ -45,14 +45,21 @@ ;;; Generic for SCRAM-* +(defvar sasl-scram-gs2-header-function 'sasl-scram-construct-gs2-header + "Function to create GS2 header. +See https://www.rfc-editor.org/rfc/rfc5801#section-4.") + +(defun sasl-scram-construct-gs2-header (client) + ;; The "n," means the client doesn't support channel binding, and + ;; the trailing comma is included as per RFC 5801. + (let ((authzid (sasl-client-property client 'authenticator-name))) + (concat "n," (and authzid "a=") authzid ","))) + (defun sasl-scram-client-first-message (client _step) (let ((c-nonce (sasl-unique-id))) (sasl-client-set-property client 'c-nonce c-nonce)) (concat - ;; n = client doesn't support channel binding - "n," - ;; TODO: where would we get authorization id from? - "," + (funcall sasl-scram-gs2-header-function client) (sasl-scram--client-first-message-bare client))) (defun sasl-scram--client-first-message-bare (client) @@ -77,11 +84,11 @@ sasl-scram--client-final-message (c-nonce (sasl-client-property client 'c-nonce)) ;; no channel binding, no authorization id - (cbind-input "n,,")) + (cbind-input (funcall sasl-scram-gs2-header-function client))) (unless (string-prefix-p c-nonce nonce) (sasl-error "Invalid nonce from server")) (let* ((client-final-message-without-proof - (concat "c=" (base64-encode-string cbind-input) "," + (concat "c=" (base64-encode-string cbind-input t) "," "r=" nonce)) (password ;; TODO: either apply saslprep or disallow non-ASCII characters @@ -113,7 +120,7 @@ sasl-scram--client-final-message (client-proof (funcall string-xor client-key client-signature)) (client-final-message (concat client-final-message-without-proof "," - "p=" (base64-encode-string client-proof)))) + "p=" (base64-encode-string client-proof t)))) (sasl-client-set-property client 'auth-message auth-message) (sasl-client-set-property client 'salted-password salted-password) client-final-message))) -- 2.37.3