Fix #236: Prevent fabricated epoch timestamps before NTP synchronization#237
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Psykii22 wants to merge 1 commit intoarduino-libraries:masterfrom
Open
Fix #236: Prevent fabricated epoch timestamps before NTP synchronization#237Psykii22 wants to merge 1 commit intoarduino-libraries:masterfrom
Psykii22 wants to merge 1 commit intoarduino-libraries:masterfrom
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… NTP synchronization
This commit implements a two-layer security fix to address the vulnerability
where getEpochTime() returned fabricated values (device uptime) before NTP
synchronization completed.
Security Issue:
- Before fix: getEpochTime() returned millis()/1000 (uptime values like 14, 16, 17...)
- These fabricated values could be mistaken for valid epoch timestamps
- Created authentication bypass vulnerabilities in security-sensitive applications
- Systems using timestamps for auth, replay protection, or HMAC were at risk
Layer 1 - Core Fix (getEpochTime):
- Now returns 0 when _lastUpdate == 0 (before synchronization)
- Aligns with ESP32 native SNTP behavior (time(nullptr) returns 0 until sync)
- Prevents fabricated values from being generated
- Fail-safe protection even if developers forget to check sync status
Layer 2 - Enhanced Validation (isTimeValid):
- New method that checks BOTH synchronization AND epoch reasonableness
- Returns true only if time is set AND epoch > 946684800 (Jan 1, 2000)
- Recommended for security-sensitive applications
- Catches edge cases where time might be "set" but invalid
Backward Compatibility:
- Existing isTimeSet() method unchanged
- Code checking isTimeSet() before using getEpochTime() continues to work
- New isTimeValid() is optional but recommended for security
- No breaking changes to existing functionality
Usage:
// For UI/display:
if (timeClient.isTimeSet()) {
Serial.println(timeClient.getFormattedTime());
}
// For security operations:
if (timeClient.isTimeValid()) {
generateAuthToken(timeClient.getEpochTime());
}
Fixes arduino-libraries#236
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Memory usage change @ 8a3e6c6
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This commit implements a two-layer security fix to address the vulnerability where getEpochTime() returned fabricated values (device uptime) before NTP synchronization completed.
Security Issue:
Layer 1 - Core Fix (getEpochTime):
Layer 2 - Enhanced Validation (isTimeValid):
Backward Compatibility:
Usage:
// For UI/display: if (timeClient.isTimeSet()) { Serial.println(timeClient.getFormattedTime()); }
// For security operations: if (timeClient.isTimeValid()) { generateAuthToken(timeClient.getEpochTime()); }
Fixes #236