Merge pull request #1385 from crytic/read-storage-from-block

Read storage from block

.gitignore

@@ -47,6 +47,7 @@ coverage.xml
 *.cover
 .hypothesis/
 .vscode/
+storage_layout.json
 # Translations
 *.mo
 *.pot

slither/tools/read_storage/README.md

@@ -21,6 +21,7 @@ optional arguments:
   --json FILE                       Write the entire storage layout in JSON format to the specified FILE
   --value                           Toggle used to include values in output.
   --max-depth MAX_DEPTH             Max depth to search in data structure.
+  --block BLOCK_NUMBER              Block number to retrieve storage from (requires archive rpc node)
 ```
 
 ### Examples

slither/tools/read_storage/__main__.py

@@ -98,6 +98,12 @@ def parse_args() -> argparse.Namespace:
 
     parser.add_argument("--max-depth", help="Max depth to search in data structure.", default=20)
 
+    parser.add_argument(
+        "--block",
+        help="The block number to read storage from. Requires an archive node to be provided as the RPC url.",
+        default="latest",
+    )
+
     cryticparser.init(parser)
 
     return parser.parse_args()
@@ -122,6 +128,11 @@ def main() -> None:
 
     srs = SlitherReadStorage(contracts, args.max_depth)
 
+    try:
+        srs.block = int(args.block)
+    except ValueError:
+        srs.block = str(args.block or "latest")
+
     if args.rpc_url:
         # Remove target prefix e.g. rinkeby:0x0 -> 0x0.
         address = target[target.find(":") + 1 :]

slither/tools/read_storage/read_storage.py

@@ -53,15 +53,16 @@ class SlitherReadStorageException(Exception):
 # pylint: disable=too-many-instance-attributes
 class SlitherReadStorage:
     def __init__(self, contracts: List[Contract], max_depth: int) -> None:
+        self._checksum_address: Optional[ChecksumAddress] = None
         self._contracts: List[Contract] = contracts
-        self._max_depth: int = max_depth
         self._log: str = ""
+        self._max_depth: int = max_depth
         self._slot_info: Dict[str, SlotInfo] = {}
         self._target_variables: List[Tuple[Contract, StateVariable]] = []
         self._web3: Optional[Web3] = None
-        self._checksum_address: Optional[ChecksumAddress] = None
-        self.storage_address: Optional[str] = None
+        self.block: Union[str, int] = "latest"
         self.rpc: Optional[str] = None
+        self.storage_address: Optional[str] = None
         self.table: Optional[MyPrettyTable] = None
 
     @property
@@ -231,7 +232,10 @@ class SlitherReadStorage:
         :param slot_info:
         """
         hex_bytes = get_storage_data(
-            self.web3, self.checksum_address, int.to_bytes(slot_info.slot, 32, byteorder="big")
+            self.web3,
+            self.checksum_address,
+            int.to_bytes(slot_info.slot, 32, byteorder="big"),
+            self.block,
         )
         slot_info.value = self.convert_value_to_type(
             hex_bytes, slot_info.size, slot_info.offset, slot_info.type_string
@@ -609,7 +613,10 @@ class SlitherReadStorage:
             # Convert from hexadecimal to decimal.
             val = int(
                 get_storage_data(
-                    self.web3, self.checksum_address, int.to_bytes(slot, 32, byteorder="big")
+                    self.web3,
+                    self.checksum_address,
+                    int.to_bytes(slot, 32, byteorder="big"),
+                    self.block,
                 ).hex(),
                 16,
             )

slither/tools/read_storage/utils/utils.py

@@ -55,16 +55,19 @@ def coerce_type(
     return value.hex()
 
 
-def get_storage_data(web3, checksum_address: ChecksumAddress, slot: bytes) -> bytes:
+def get_storage_data(
+    web3, checksum_address: ChecksumAddress, slot: bytes, block: Union[int, str]
+) -> bytes:
     """
     Retrieves the storage data from the blockchain at target address and slot.
     Args:
         web3: Web3 instance provider.
         checksum_address (ChecksumAddress): The address to query.
         slot (bytes): The slot to retrieve data from.
+        block (optional int|str): The block number to retrieve data from
     Returns:
         (HexBytes): The slot's storage data.
     """
-    return bytes(web3.eth.get_storage_at(checksum_address, slot)).rjust(
+    return bytes(web3.eth.get_storage_at(checksum_address, slot, block)).rjust(
         32, bytes(1)
     )  # pad to 32 bytes