46 lines
1.4 KiB
Go
46 lines
1.4 KiB
Go
// Copyright 2020 the Pinniped contributors. All Rights Reserved.
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// SPDX-License-Identifier: Apache-2.0
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package pkce
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"encoding/hex"
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"io"
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"github.com/pkg/errors"
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"golang.org/x/oauth2"
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)
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// Generate generates a new random PKCE code.
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func Generate() (Code, error) { return generate(rand.Reader) }
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func generate(rand io.Reader) (Code, error) {
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var buf [32]byte
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if _, err := io.ReadFull(rand, buf[:]); err != nil {
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return "", errors.WithMessage(err, "could not generate PKCE code")
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}
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return Code(hex.EncodeToString(buf[:])), nil
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}
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// Code implements the basic options required for RFC 7636: Proof Key for Code Exchange (PKCE).
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type Code string
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// Challenge returns the OAuth2 auth code parameter for sending the PKCE code challenge.
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func (p *Code) Challenge() oauth2.AuthCodeOption {
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b := sha256.Sum256([]byte(*p))
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return oauth2.SetAuthURLParam("code_challenge", base64.RawURLEncoding.EncodeToString(b[:]))
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}
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// Method returns the OAuth2 auth code parameter for sending the PKCE code challenge method.
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func (p *Code) Method() oauth2.AuthCodeOption {
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return oauth2.SetAuthURLParam("code_challenge_method", "S256")
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}
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// Verifier returns the OAuth2 auth code parameter for sending the PKCE code verifier.
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func (p *Code) Verifier() oauth2.AuthCodeOption {
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return oauth2.SetAuthURLParam("code_verifier", string(*p))
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}
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