Summary
The IBlockHashRetain.vyi interface lacks robust error handling and recovery mechanisms. This creates potential for unrecoverable states and system-wide failures.
Vulnerability Details
Current implementation has minimal error handling:
@external
def commit() -> uint256:
"""
@notice Commit (and apply) a block hash/state root.
"""
# No try-catch mechanisms
# No state recovery logic
...
@external
def apply() -> uint256:
"""
@notice Apply a block hash/state root.
"""
# Missing error states
# No fallback mechanisms
...
Critical missing components:
No fallback oracle mechanism
Missing state recovery functions
Absence of emergency pause
No graceful degradation
Lack of error classification
Impact
Potential permanent system failure
No recovery from bad states
System-wide outages possible
Data loss scenarios
Stuck transactions
Tools Used
Recommendations
Implement comprehensive error handling:
# Error states
ERROR_NONE: constant(uint8) = 0
ERROR_ORACLE_DOWN: constant(uint8) = 1
ERROR_INVALID_DATA: constant(uint8) = 2
ERROR_SYSTEM_PAUSED: constant(uint8) = 3
struct SystemState:
is_active: bool
error_code: uint8
last_good_block: uint256
recovery_attempts: uint256
system_state: public(SystemState)
fallback_oracle: public(address)
@external
def handle_oracle_error(_error_code: uint8) -> bool:
"""
@notice Handle oracle errors with fallback
"""
if _error_code == ERROR_ORACLE_DOWN:
# Try fallback oracle
if self.fallback_oracle != empty(address):
return self._try_fallback_oracle()
if _error_code == ERROR_INVALID_DATA:
return self._revert_to_last_good_state()
if self.system_state.recovery_attempts > 3:
self._emergency_pause()
return False
return True
Add recovery mechanisms:
@external
def recover_from_error() -> bool:
"""
@notice System recovery function
"""
assert msg.sender == self.admin, "Not admin"
# Try recovery based on error type
if self.system_state.error_code == ERROR_ORACLE_DOWN:
success: bool = self._reconnect_oracle()
if success:
self.system_state.error_code = ERROR_NONE
self.system_state.is_active = True
return True
elif self.system_state.error_code == ERROR_INVALID_DATA:
if self._validate_current_state():
self.system_state.error_code = ERROR_NONE
self.system_state.is_active = True
return True
self.system_state.recovery_attempts += 1
return False
Implement graceful degradation:
@view
@external
def get_safe_block_hash(_block_number: uint256) -> (bytes32, bool):
"""
@notice Get block hash with fallback mechanisms
"""
try:
primary_hash: bytes32 = self._get_primary_block_hash(_block_number)
if self._validate_hash(primary_hash):
return (primary_hash, True)
except:
pass
try:
fallback_hash: bytes32 = self._get_fallback_block_hash(_block_number)
return (fallback_hash, True)
except:
pass
return (self.last_good_hash, False)
Add emergency controls:
@external
def emergency_shutdown():
"""
@notice Emergency shutdown with state preservation
"""
assert msg.sender == self.admin, "Not admin"
# Save current state
self._save_checkpoint()
# Pause system
self.system_state.is_active = False
self.system_state.error_code = ERROR_SYSTEM_PAUSED
# Emit emergency event
log EmergencyShutdown(block.timestamp, msg.sender)
@external
def resume_from_shutdown() -> bool:
"""
@notice Resume from emergency shutdown
"""
assert msg.sender == self.admin, "Not admin"
assert self.system_state.error_code == ERROR_SYSTEM_PAUSED, "Not in shutdown"
if self._validate_checkpoint():
self.system_state.is_active = True
self.system_state.error_code = ERROR_NONE
return True
return False
These enhancements provide:
