83 lignes
2,1 Kio
Go
83 lignes
2,1 Kio
Go
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package csrf
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import (
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"net/http"
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"time"
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"github.com/gorilla/securecookie"
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)
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// store represents the session storage used for CSRF tokens.
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type store interface {
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// Get returns the real CSRF token from the store.
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Get(*http.Request) ([]byte, error)
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// Save stores the real CSRF token in the store and writes a
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// cookie to the http.ResponseWriter.
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// For non-cookie stores, the cookie should contain a unique (256 bit) ID
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// or key that references the token in the backend store.
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// csrf.GenerateRandomBytes is a helper function for generating secure IDs.
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Save(token []byte, w http.ResponseWriter) error
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}
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// cookieStore is a signed cookie session store for CSRF tokens.
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type cookieStore struct {
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name string
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maxAge int
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secure bool
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httpOnly bool
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path string
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domain string
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sc *securecookie.SecureCookie
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}
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// Get retrieves a CSRF token from the session cookie. It returns an empty token
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// if decoding fails (e.g. HMAC validation fails or the named cookie doesn't exist).
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func (cs *cookieStore) Get(r *http.Request) ([]byte, error) {
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// Retrieve the cookie from the request
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cookie, err := r.Cookie(cs.name)
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if err != nil {
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return nil, err
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}
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token := make([]byte, tokenLength)
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// Decode the HMAC authenticated cookie.
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err = cs.sc.Decode(cs.name, cookie.Value, &token)
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if err != nil {
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return nil, err
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}
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return token, nil
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}
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// Save stores the CSRF token in the session cookie.
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func (cs *cookieStore) Save(token []byte, w http.ResponseWriter) error {
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// Generate an encoded cookie value with the CSRF token.
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encoded, err := cs.sc.Encode(cs.name, token)
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if err != nil {
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return err
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}
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cookie := &http.Cookie{
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Name: cs.name,
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Value: encoded,
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MaxAge: cs.maxAge,
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HttpOnly: cs.httpOnly,
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Secure: cs.secure,
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Path: cs.path,
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Domain: cs.domain,
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}
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// Set the Expires field on the cookie based on the MaxAge
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// If MaxAge <= 0, we don't set the Expires attribute, making the cookie
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// session-only.
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if cs.maxAge > 0 {
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cookie.Expires = time.Now().Add(
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time.Duration(cs.maxAge) * time.Second)
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}
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// Write the authenticated cookie to the response.
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http.SetCookie(w, cookie)
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return nil
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}
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