getNtpTime() doesn't handle zero from NTP server response
Anton-V-K opened this issue · comments
Anton-V-K commented
The code of getNtpTime()
in https://github.com/PaulStoffregen/Time/blob/master/examples/TimeNTP/TimeNTP.ino doesn't check the correctness of UDP packet's content (obtained from NTP server), and can potentially set invalid date (in future - 07-Feb-2036).
I'm referring to this code fragment:
if (size >= NTP_PACKET_SIZE) {
Serial.println("Receive NTP Response");
Udp.read(packetBuffer, NTP_PACKET_SIZE); // read packet into the buffer
unsigned long secsSince1900;
// convert four bytes starting at location 40 to a long integer
secsSince1900 = (unsigned long)packetBuffer[40] << 24;
secsSince1900 |= (unsigned long)packetBuffer[41] << 16;
secsSince1900 |= (unsigned long)packetBuffer[42] << 8;
secsSince1900 |= (unsigned long)packetBuffer[43];
return secsSince1900 - 2208988800UL + timeZone * SECS_PER_HOUR;
}
Here secsSince1900
can be zero, when in certain cases ( like "rate limiting" - mentioned in arduino-libraries/NTPClient#84 ) NTP responds with zero time.
gednz commented
I am having this issue too