feat: IsASafe.isProbablyASafe

Author: wjmelements

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "lib/forge-std"]
 	path = lib/forge-std
 	url = https://github.com/foundry-rs/forge-std
+[submodule "lib/safe-smart-account"]
+	path = lib/safe-smart-account
+	url = https://github.com/safe-fndn/safe-smart-account

foundry.lock

@@ -4,5 +4,11 @@
       "name": "v1.16.2",
       "rev": "bf647bd6046f2f7da30d0c2bf435e5c76a780c1b"
     }
+  },
+  "lib/safe-smart-account": {
+    "tag": {
+      "name": "v1.5.0",
+      "rev": "dc437e8fba8b4805d76bcbd1c668c9fd3d1e83be"
+    }
   }
 }

foundry.toml

@@ -14,6 +14,7 @@ bytecode_hash = "none"
 # For dependencies
 remappings = [
     'forge-std/=lib/forge-std/src/',
+    '@safe/=lib/safe-smart-account/contracts/',
     #'@fvm-solidity/=lib/pdp/lib/fvm-solidity/src/',
 ]
 

lib/safe-smart-account

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+pragma solidity ^0.8.36;
+
+import {IProxy} from "@safe/proxies/SafeProxy.sol";
+
+library IsASafe {
+    error NotSafeProxy(address account);
+    error UnusualSafeMasterCopy(address account, address masterCopy);
+
+    function isProbablyASafe(address account) internal view {
+        uint256 codesize = account.code.length;
+        // observed Safe proxy codesize range is 110 (v1.0.0) to 171 (v1.3.0)
+        require(codesize > 80 && codesize < 240, NotSafeProxy(account));
+        address implementation = IProxy(account).masterCopy();
+        // observed Safe masterCopy size is 20869 (v1.5.0) to 24421 (v1.4.1)
+        require(implementation.code.length > 8000, UnusualSafeMasterCopy(account, implementation));
+    }
+}