93 lines
2.4 KiB
Go
93 lines
2.4 KiB
Go
// Copyright (c) 2025-2026 Probo Inc <hello@probo.com>.
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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// PERFORMANCE OF THIS SOFTWARE.
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package securetoken
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import (
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"crypto/hmac"
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"crypto/sha256"
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"crypto/subtle"
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"encoding/base64"
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"errors"
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"fmt"
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"net/http"
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"strings"
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"go.probo.inc/probo/pkg/bearertoken"
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)
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var (
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ErrInvalidToken = errors.New("invalid token")
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ErrTokenNotFound = errors.New("token not found")
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ErrInvalidSignature = errors.New("invalid signature")
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)
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func Get(req *http.Request, secret string) (string, error) {
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v := req.Header.Get("Authorization")
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if v == "" {
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return "", ErrTokenNotFound
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}
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token, err := bearertoken.Parse(v)
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if err != nil {
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return "", ErrInvalidToken
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}
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value, err := Verify(token, secret)
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if err != nil {
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return "", ErrInvalidToken
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}
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return value, nil
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}
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// Sign creates a signed value using HMAC-SHA256
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func Sign(value, secret string) (string, error) {
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if secret == "" {
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return "", fmt.Errorf("secret cannot be empty")
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}
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h := hmac.New(sha256.New, []byte(secret))
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h.Write([]byte(value))
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signature := base64.RawURLEncoding.EncodeToString(h.Sum(nil))
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return value + "." + signature, nil
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}
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// Verify checks if a signed value is valid
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func Verify(signedValue, secret string) (string, error) {
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if secret == "" {
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return "", fmt.Errorf("secret cannot be empty")
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}
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parts := strings.Split(signedValue, ".")
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if len(parts) != 2 {
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return "", fmt.Errorf("invalid signed value format")
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}
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value := parts[0]
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expectedSignedValue, err := Sign(value, secret)
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if err != nil {
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return "", fmt.Errorf("cannot sign value: %w", err)
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}
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if subtle.ConstantTimeCompare([]byte(signedValue), []byte(expectedSignedValue)) != 1 {
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return "", ErrInvalidSignature
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}
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return value, nil
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}
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