Method initLegacySessionTicketKeyRLocked

common.go:1029–1055

initLegacySessionTicketKeyRLocked ensures the legacy SessionTicketKey field is randomized if empty, and that sessionTicketKeys is populated from it otherwise.

()

// initLegacySessionTicketKeyRLocked ensures the legacy SessionTicketKey field is
// randomized if empty, and that sessionTicketKeys is populated from it otherwise.
func (c *Config) initLegacySessionTicketKeyRLocked() {
	// Don't write if SessionTicketKey is already defined as our deprecated string,
	// or if it is defined by the user but sessionTicketKeys is already set.
	if c.SessionTicketKey != [32]byte{} &&
		(bytes.HasPrefix(c.SessionTicketKey[:], deprecatedSessionTicketKey) || len(c.sessionTicketKeys) > 0) {
		return
	}

	// We need to write some data, so get an exclusive lock and re-check any conditions.
	c.mutex.RUnlock()
	defer c.mutex.RLock()
	c.mutex.Lock()
	defer c.mutex.Unlock()
	if c.SessionTicketKey == [32]byte{} {
		if _, err := io.ReadFull(c.rand(), c.SessionTicketKey[:]); err != nil {
			panic(fmt.Sprintf("tls: unable to generate random session ticket key: %v", err))
		}
		// Write the deprecated prefix at the beginning so we know we created
		// it. This key with the DEPRECATED prefix isn't used as an actual
		// session ticket key, and is only randomized in case the application
		// reuses it for some reason.
		copy(c.SessionTicketKey[:], deprecatedSessionTicketKey)
	} else if !bytes.HasPrefix(c.SessionTicketKey[:], deprecatedSessionTicketKey) && len(c.sessionTicketKeys) == 0 {
		c.sessionTicketKeys = []ticketKey{c.ticketKeyFromBytes(c.SessionTicketKey)}
	}

}

// ticketKeys returns the ticketKeys for this connection.
// If configForClient has explicitly set keys, those will