Swift: add flow for self out of constructors

Author: Robert Marsh

swift/ql/lib/codeql/swift/dataflow/internal/DataFlowPrivate.qll

@@ -399,6 +399,29 @@ private module ReturnNodes {
     override ReturnKind getKind() { result instanceof NormalReturnKind }
   }
 
+  class SelfReturnNode extends ReturnNode, TInoutReturnNode, NodeImpl {
+    SelfParamDecl param;
+    ControlFlowNode exit;
+    SelfReturnNode() {
+      this = TInoutReturnNode(param) and
+      exit instanceof ExitNode and
+      exit.getScope() = param.getDeclaringFunction() and
+      param.getDeclaringFunction() instanceof ConstructorDecl
+    }
+    override ControlFlowNode getCfgNode() { result = exit }
+
+    override DataFlowCallable getEnclosingCallable() {
+      result = TDataFlowFunc(param.getDeclaringFunction())
+    }
+
+    ParamDecl getParameter() { result = param }
+
+    override Location getLocationImpl() { result = exit.getLocation() }
+
+    override string toStringImpl() { result = param.toString() + "[constructor return]" }
+    override ReturnKind getKind() { result instanceof NormalReturnKind }
+  }
+
   class InoutReturnNodeImpl extends ReturnNode, TInoutReturnNode, NodeImpl {
     ParamDecl param;
     ControlFlowNode exit;

swift/ql/test/library-tests/dataflow/dataflow/DataFlow.expected

@@ -1,6 +1,7 @@
 edges
 | file://:0:0:0:0 | [summary param] this in signum() :  | file://:0:0:0:0 | [summary] to write: return (return) in signum() :  |
 | file://:0:0:0:0 | self [a, x] :  | file://:0:0:0:0 | .a [x] :  |
+| file://:0:0:0:0 | self [str] :  | file://:0:0:0:0 | .str :  |
 | file://:0:0:0:0 | self [x] :  | file://:0:0:0:0 | .x :  |
 | file://:0:0:0:0 | self [x] :  | file://:0:0:0:0 | .x :  |
 | file://:0:0:0:0 | value :  | file://:0:0:0:0 | [post] self [x] :  |
@@ -155,22 +156,36 @@ edges
 | test.swift:472:20:472:20 | cx [x] :  | test.swift:472:20:472:23 | .x :  |
 | test.swift:472:20:472:23 | .x :  | test.swift:473:15:473:15 | z1 |
 | test.swift:479:14:479:21 | call to source() :  | test.swift:479:13:479:21 | call to +(_:) |
+| test.swift:488:9:488:9 | self [str] :  | file://:0:0:0:0 | self [str] :  |
 | test.swift:489:10:489:13 | s :  | test.swift:490:13:490:13 | s :  |
+| test.swift:490:7:490:7 | [post] self [str] :  | test.swift:489:5:491:5 | self[constructor return] [str] :  |
 | test.swift:490:7:490:7 | [post] self [str] :  | test.swift:489:5:491:5 | self[return] [str] :  |
 | test.swift:490:13:490:13 | s :  | test.swift:490:7:490:7 | [post] self [str] :  |
+| test.swift:495:17:498:5 | self[constructor return] [str] :  | test.swift:503:13:503:41 | call to Self.init(contentsOfFile:) [str] :  |
+| test.swift:495:17:498:5 | self[return] [str] :  | test.swift:503:13:503:41 | call to Self.init(contentsOfFile:) [str] :  |
+| test.swift:496:7:496:7 | [post] self [str] :  | test.swift:495:17:498:5 | self[constructor return] [str] :  |
+| test.swift:496:7:496:7 | [post] self [str] :  | test.swift:495:17:498:5 | self[return] [str] :  |
 | test.swift:496:7:496:7 | [post] self [str] :  | test.swift:497:17:497:17 | self [str] :  |
 | test.swift:496:20:496:28 | call to source3() :  | test.swift:489:10:489:13 | s :  |
 | test.swift:496:20:496:28 | call to source3() :  | test.swift:496:7:496:7 | [post] self [str] :  |
 | test.swift:497:17:497:17 | self [str] :  | test.swift:497:17:497:17 | .str |
+| test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  | test.swift:488:9:488:9 | self [str] :  |
+| test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  | test.swift:502:13:502:35 | .str |
+| test.swift:502:24:502:32 | call to source3() :  | test.swift:489:10:489:13 | s :  |
+| test.swift:502:24:502:32 | call to source3() :  | test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  |
+| test.swift:503:13:503:41 | call to Self.init(contentsOfFile:) [str] :  | test.swift:488:9:488:9 | self [str] :  |
+| test.swift:503:13:503:41 | call to Self.init(contentsOfFile:) [str] :  | test.swift:503:13:503:43 | .str |
 nodes
 | file://:0:0:0:0 | .a [x] :  | semmle.label | .a [x] :  |
+| file://:0:0:0:0 | .str :  | semmle.label | .str :  |
 | file://:0:0:0:0 | .x :  | semmle.label | .x :  |
 | file://:0:0:0:0 | .x :  | semmle.label | .x :  |
 | file://:0:0:0:0 | [post] self [x] :  | semmle.label | [post] self [x] :  |
 | file://:0:0:0:0 | [post] self [x] :  | semmle.label | [post] self [x] :  |
 | file://:0:0:0:0 | [summary param] this in signum() :  | semmle.label | [summary param] this in signum() :  |
 | file://:0:0:0:0 | [summary] to write: return (return) in signum() :  | semmle.label | [summary] to write: return (return) in signum() :  |
 | file://:0:0:0:0 | self [a, x] :  | semmle.label | self [a, x] :  |
+| file://:0:0:0:0 | self [str] :  | semmle.label | self [str] :  |
 | file://:0:0:0:0 | self [x] :  | semmle.label | self [x] :  |
 | file://:0:0:0:0 | self [x] :  | semmle.label | self [x] :  |
 | file://:0:0:0:0 | value :  | semmle.label | value :  |
@@ -335,14 +350,27 @@ nodes
 | test.swift:479:13:479:21 | call to +(_:) | semmle.label | call to +(_:) |
 | test.swift:479:14:479:21 | call to source() :  | semmle.label | call to source() :  |
 | test.swift:480:14:480:21 | call to source() | semmle.label | call to source() |
+| test.swift:488:9:488:9 | self [str] :  | semmle.label | self [str] :  |
+| test.swift:489:5:491:5 | self[constructor return] [str] :  | semmle.label | self[constructor return] [str] :  |
+| test.swift:489:5:491:5 | self[constructor return] [str] :  | semmle.label | self[return] [str] :  |
+| test.swift:489:5:491:5 | self[return] [str] :  | semmle.label | self[constructor return] [str] :  |
 | test.swift:489:5:491:5 | self[return] [str] :  | semmle.label | self[return] [str] :  |
 | test.swift:489:10:489:13 | s :  | semmle.label | s :  |
 | test.swift:490:7:490:7 | [post] self [str] :  | semmle.label | [post] self [str] :  |
 | test.swift:490:13:490:13 | s :  | semmle.label | s :  |
+| test.swift:495:17:498:5 | self[constructor return] [str] :  | semmle.label | self[constructor return] [str] :  |
+| test.swift:495:17:498:5 | self[constructor return] [str] :  | semmle.label | self[return] [str] :  |
+| test.swift:495:17:498:5 | self[return] [str] :  | semmle.label | self[constructor return] [str] :  |
+| test.swift:495:17:498:5 | self[return] [str] :  | semmle.label | self[return] [str] :  |
 | test.swift:496:7:496:7 | [post] self [str] :  | semmle.label | [post] self [str] :  |
 | test.swift:496:20:496:28 | call to source3() :  | semmle.label | call to source3() :  |
 | test.swift:497:17:497:17 | .str | semmle.label | .str |
 | test.swift:497:17:497:17 | self [str] :  | semmle.label | self [str] :  |
+| test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  | semmle.label | call to MyClass.init(s:) [str] :  |
+| test.swift:502:13:502:35 | .str | semmle.label | .str |
+| test.swift:502:24:502:32 | call to source3() :  | semmle.label | call to source3() :  |
+| test.swift:503:13:503:41 | call to Self.init(contentsOfFile:) [str] :  | semmle.label | call to Self.init(contentsOfFile:) [str] :  |
+| test.swift:503:13:503:43 | .str | semmle.label | .str |
 subpaths
 | test.swift:75:21:75:22 | &... :  | test.swift:65:16:65:28 | arg1 :  | test.swift:65:1:70:1 | arg2[return] :  | test.swift:75:31:75:32 | [post] &... :  |
 | test.swift:114:19:114:19 | arg :  | test.swift:109:9:109:14 | arg :  | test.swift:110:12:110:12 | arg :  | test.swift:114:12:114:22 | call to ... :  |
@@ -375,8 +403,13 @@ subpaths
 | test.swift:303:15:303:16 | ...! :  | file://:0:0:0:0 | [summary param] this in signum() :  | file://:0:0:0:0 | [summary] to write: return (return) in signum() :  | test.swift:303:15:303:25 | call to signum() |
 | test.swift:468:12:468:12 | x :  | test.swift:462:9:462:9 | value :  | file://:0:0:0:0 | [post] self [x] :  | test.swift:468:5:468:5 | [post] cx [x] :  |
 | test.swift:472:20:472:20 | cx [x] :  | test.swift:462:9:462:9 | self [x] :  | file://:0:0:0:0 | .x :  | test.swift:472:20:472:23 | .x :  |
+| test.swift:496:20:496:28 | call to source3() :  | test.swift:489:10:489:13 | s :  | test.swift:489:5:491:5 | self[constructor return] [str] :  | test.swift:496:7:496:7 | [post] self [str] :  |
 | test.swift:496:20:496:28 | call to source3() :  | test.swift:489:10:489:13 | s :  | test.swift:489:5:491:5 | self[return] [str] :  | test.swift:496:7:496:7 | [post] self [str] :  |
 | test.swift:496:20:496:28 | call to source3() :  | test.swift:489:10:489:13 | s :  | test.swift:490:7:490:7 | [post] self [str] :  | test.swift:496:7:496:7 | [post] self [str] :  |
+| test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  | test.swift:488:9:488:9 | self [str] :  | file://:0:0:0:0 | .str :  | test.swift:502:13:502:35 | .str |
+| test.swift:502:24:502:32 | call to source3() :  | test.swift:489:10:489:13 | s :  | test.swift:489:5:491:5 | self[constructor return] [str] :  | test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  |
+| test.swift:502:24:502:32 | call to source3() :  | test.swift:489:10:489:13 | s :  | test.swift:489:5:491:5 | self[return] [str] :  | test.swift:502:13:502:33 | call to MyClass.init(s:) [str] :  |
+| test.swift:503:13:503:41 | call to Self.init(contentsOfFile:) [str] :  | test.swift:488:9:488:9 | self [str] :  | file://:0:0:0:0 | .str :  | test.swift:503:13:503:43 | .str |
 #select
 | test.swift:7:15:7:15 | t1 | test.swift:6:19:6:26 | call to source() :  | test.swift:7:15:7:15 | t1 | result |
 | test.swift:9:15:9:15 | t1 | test.swift:6:19:6:26 | call to source() :  | test.swift:9:15:9:15 | t1 | result |
@@ -432,3 +465,5 @@ subpaths
 | test.swift:479:13:479:21 | call to +(_:) | test.swift:479:14:479:21 | call to source() :  | test.swift:479:13:479:21 | call to +(_:) | result |
 | test.swift:480:14:480:21 | call to source() | test.swift:480:14:480:21 | call to source() | test.swift:480:14:480:21 | call to source() | result |
 | test.swift:497:17:497:17 | .str | test.swift:496:20:496:28 | call to source3() :  | test.swift:497:17:497:17 | .str | result |
+| test.swift:502:13:502:35 | .str | test.swift:502:24:502:32 | call to source3() :  | test.swift:502:13:502:35 | .str | result |
+| test.swift:503:13:503:43 | .str | test.swift:496:20:496:28 | call to source3() :  | test.swift:503:13:503:43 | .str | result |

swift/ql/test/library-tests/dataflow/dataflow/DataFlowInline.expected

@@ -1 +0,0 @@
-| test.swift:497:17:497:17 | .str | Unexpected result: flow=496 |

swift/ql/test/library-tests/dataflow/dataflow/LocalFlow.expected

@@ -115,7 +115,9 @@
 | test.swift:163:7:163:7 | value | test.swift:163:7:163:7 | SSA def(value) |
 | test.swift:165:3:165:3 | SSA def(self) | test.swift:166:5:166:5 | self |
 | test.swift:165:3:165:3 | self | test.swift:165:3:165:3 | SSA def(self) |
+| test.swift:166:5:166:5 | [post] self | test.swift:165:3:167:3 | self[constructor return] |
 | test.swift:166:5:166:5 | [post] self | test.swift:165:3:167:3 | self[return] |
+| test.swift:166:5:166:5 | self | test.swift:165:3:167:3 | self[constructor return] |
 | test.swift:166:5:166:5 | self | test.swift:165:3:167:3 | self[return] |
 | test.swift:169:8:169:8 | SSA def(self) | test.swift:170:5:170:5 | self |
 | test.swift:169:8:169:8 | self | test.swift:169:8:169:8 | SSA def(self) |
@@ -139,7 +141,9 @@
 | test.swift:185:7:185:7 | value | test.swift:185:7:185:7 | SSA def(value) |
 | test.swift:187:3:187:3 | SSA def(self) | test.swift:188:5:188:5 | self |
 | test.swift:187:3:187:3 | self | test.swift:187:3:187:3 | SSA def(self) |
+| test.swift:188:5:188:5 | [post] self | test.swift:187:3:189:3 | self[constructor return] |
 | test.swift:188:5:188:5 | [post] self | test.swift:187:3:189:3 | self[return] |
+| test.swift:188:5:188:5 | self | test.swift:187:3:189:3 | self[constructor return] |
 | test.swift:188:5:188:5 | self | test.swift:187:3:189:3 | self[return] |
 | test.swift:193:7:193:7 | SSA def(b) | test.swift:194:3:194:3 | b |
 | test.swift:193:11:193:13 | call to B.init() | test.swift:193:7:193:7 | SSA def(b) |
@@ -161,6 +165,7 @@
 | test.swift:217:11:217:13 | call to B.init() | test.swift:217:7:217:7 | SSA def(b) |
 | test.swift:218:3:218:3 | [post] b | test.swift:219:13:219:13 | b |
 | test.swift:218:3:218:3 | b | test.swift:219:13:219:13 | b |
+| test.swift:222:7:222:7 | SSA def(self) | test.swift:222:7:222:7 | self[constructor return] |
 | test.swift:222:7:222:7 | SSA def(self) | test.swift:222:7:222:7 | self[return] |
 | test.swift:222:7:222:7 | SSA def(self) | test.swift:222:7:222:7 | self[return] |
 | test.swift:222:7:222:7 | self | test.swift:222:7:222:7 | SSA def(self) |
@@ -186,7 +191,9 @@
 | test.swift:243:18:243:18 | self | test.swift:243:9:243:42 | self[return] |
 | test.swift:246:5:246:5 | SSA def(self) | test.swift:247:9:247:9 | self |
 | test.swift:246:5:246:5 | self | test.swift:246:5:246:5 | SSA def(self) |
+| test.swift:247:9:247:9 | [post] self | test.swift:246:5:248:5 | self[constructor return] |
 | test.swift:247:9:247:9 | [post] self | test.swift:246:5:248:5 | self[return] |
+| test.swift:247:9:247:9 | self | test.swift:246:5:248:5 | self[constructor return] |
 | test.swift:247:9:247:9 | self | test.swift:246:5:248:5 | self[return] |
 | test.swift:252:23:252:23 | value | test.swift:252:23:252:23 | SSA def(value) |
 | test.swift:262:21:262:27 | SSA def(y) | test.swift:266:15:266:15 | y |
@@ -366,6 +373,7 @@
 | test.swift:448:10:448:37 | SSA def(b) | test.swift:450:19:450:19 | b |
 | test.swift:455:8:455:17 | SSA def(x) | test.swift:456:19:456:19 | x |
 | test.swift:455:8:455:17 | SSA def(y) | test.swift:457:19:457:19 | y |
+| test.swift:461:7:461:7 | SSA def(self) | test.swift:461:7:461:7 | self[constructor return] |
 | test.swift:461:7:461:7 | SSA def(self) | test.swift:461:7:461:7 | self[return] |
 | test.swift:461:7:461:7 | SSA def(self) | test.swift:461:7:461:7 | self[return] |
 | test.swift:461:7:461:7 | self | test.swift:461:7:461:7 | SSA def(self) |
@@ -401,13 +409,17 @@
 | test.swift:489:5:489:5 | self | test.swift:489:5:489:5 | SSA def(self) |
 | test.swift:489:10:489:13 | SSA def(s) | test.swift:490:13:490:13 | s |
 | test.swift:489:10:489:13 | s | test.swift:489:10:489:13 | SSA def(s) |
+| test.swift:490:7:490:7 | [post] self | test.swift:489:5:491:5 | self[constructor return] |
 | test.swift:490:7:490:7 | [post] self | test.swift:489:5:491:5 | self[return] |
+| test.swift:490:7:490:7 | self | test.swift:489:5:491:5 | self[constructor return] |
 | test.swift:490:7:490:7 | self | test.swift:489:5:491:5 | self[return] |
 | test.swift:495:17:495:17 | SSA def(self) | test.swift:496:7:496:7 | self |
 | test.swift:495:17:495:17 | self | test.swift:495:17:495:17 | SSA def(self) |
 | test.swift:496:7:496:7 | [post] self | test.swift:497:17:497:17 | self |
 | test.swift:496:7:496:7 | self | test.swift:497:17:497:17 | self |
+| test.swift:497:17:497:17 | [post] self | test.swift:495:17:498:5 | self[constructor return] |
 | test.swift:497:17:497:17 | [post] self | test.swift:495:17:498:5 | self[return] |
+| test.swift:497:17:497:17 | self | test.swift:495:17:498:5 | self[constructor return] |
 | test.swift:497:17:497:17 | self | test.swift:495:17:498:5 | self[return] |
 | test.swift:501:21:501:27 | SSA def(path) | test.swift:503:37:503:37 | path |
 | test.swift:501:21:501:27 | path | test.swift:501:21:501:27 | SSA def(path) |

swift/ql/test/library-tests/dataflow/dataflow/test.swift

@@ -493,12 +493,12 @@ class MyClass {
 
 extension MyClass {
     convenience init(contentsOfFile: String) {
-      self.init(s: source3()) // taint should flow from the source String(contentsOfFile:) into MyClass
-      sink(str: str)
+      self.init(s: source3()) 
+      sink(str: str) // $ flow=496
     }
 }
 
 func extensionInits(path: String) {
-  sink(str: MyClass(s: source3()).str)
-  sink(str: MyClass(contentsOfFile: path).str)
+  sink(str: MyClass(s: source3()).str) // $ flow=502
+  sink(str: MyClass(contentsOfFile: path).str) // $ flow=496
 }