77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
// Copyright (c) 2025 Probo Inc <hello@getprobo.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 saferedirect
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import (
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"net/http"
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"net/url"
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"strings"
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)
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type (
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SafeRedirect struct {
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AllowedHost string
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}
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)
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func (sr *SafeRedirect) Validate(redirectURL string) (string, bool) {
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if redirectURL == "" {
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return "", false
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}
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if strings.HasPrefix(redirectURL, "/") {
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if len(redirectURL) > 1 && (redirectURL[1] == '/' || redirectURL[1] == '\\') {
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return "", false
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}
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return redirectURL, true
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}
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parsedURL, err := url.Parse(redirectURL)
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if err != nil {
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return "", false
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}
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if parsedURL.IsAbs() {
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if parsedURL.Scheme != "http" && parsedURL.Scheme != "https" {
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return "", false
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}
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if sr.AllowedHost != "" && parsedURL.Host != sr.AllowedHost {
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return "", false
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}
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return redirectURL, true
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}
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return "", false
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}
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func (sr *SafeRedirect) GetSafeRedirectURL(redirectURL, fallbackURL string) string {
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if safeURL, isValid := sr.Validate(redirectURL); isValid {
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return safeURL
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}
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return fallbackURL
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}
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func (sr *SafeRedirect) Redirect(w http.ResponseWriter, r *http.Request, redirectURL, fallbackURL string, statusCode int) {
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safeURL := sr.GetSafeRedirectURL(redirectURL, fallbackURL)
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http.Redirect(w, r, safeURL, statusCode)
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}
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func (sr *SafeRedirect) RedirectFromQuery(w http.ResponseWriter, r *http.Request, paramName, fallbackURL string, statusCode int) {
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redirectURL := r.URL.Query().Get(paramName)
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sr.Redirect(w, r, redirectURL, fallbackURL, statusCode)
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}
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