Merge pull request #14303 from hvitved/ruby/must-flow

Ruby: Implement `localMustFlowStep `

Author: hvitved

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

@@ -1972,7 +1972,26 @@ private predicate mustHaveCollectionType(Node n, DataFlowType t) {
   not n instanceof SynthSplatParameterNode
 }
 
-predicate localMustFlowStep(Node node1, Node node2) { none() }
+predicate localMustFlowStep(Node node1, Node node2) {
+  node1 = SsaFlow::toParameterNodeImpl(node2)
+  or
+  exists(SsaImpl::Definition def |
+    def.(Ssa::WriteDefinition).assigns(node1.asExpr()) and
+    node2.(SsaDefinitionExtNode).getDefinitionExt() = def
+    or
+    def = node1.(SsaDefinitionExtNode).getDefinitionExt() and
+    node2.asExpr() = SsaImpl::getARead(def)
+  )
+  or
+  node1.asExpr() = node2.asExpr().(CfgNodes::ExprNodes::AssignExprCfgNode).getRhs()
+  or
+  node1.asExpr() = node2.asExpr().(CfgNodes::ExprNodes::BlockArgumentCfgNode).getValue()
+  or
+  node2.(ImplicitBlockArgumentNode).getParameterNode(_) = node1
+  or
+  FlowSummaryImpl::Private::Steps::summaryLocalMustFlowStep(node1.(FlowSummaryNode).getSummaryNode(),
+    node2.(FlowSummaryNode).getSummaryNode())
+}
 
 /** Gets the type of `n` used for type pruning. */
 DataFlowType getNodeType(Node n) {

ruby/ql/test/library-tests/dataflow/call-sensitivity/call-sensitivity.expected

@@ -74,11 +74,9 @@ edges
 | call_sensitivity.rb:194:17:194:17 | x | call_sensitivity.rb:189:19:189:19 | x | provenance |  |
 | call_sensitivity.rb:194:23:194:23 | x | call_sensitivity.rb:195:11:195:11 | x | provenance |  |
 | call_sensitivity.rb:195:11:195:11 | x | call_sensitivity.rb:199:30:199:30 | x | provenance |  |
-| call_sensitivity.rb:195:11:195:11 | x | call_sensitivity.rb:203:26:203:26 | x | provenance |  |
 | call_sensitivity.rb:199:15:199:24 | ( ... ) | call_sensitivity.rb:193:19:193:19 | x | provenance |  |
 | call_sensitivity.rb:199:16:199:23 | call to taint | call_sensitivity.rb:199:15:199:24 | ( ... ) | provenance |  |
 | call_sensitivity.rb:199:30:199:30 | x | call_sensitivity.rb:200:8:200:8 | x | provenance |  |
-| call_sensitivity.rb:203:26:203:26 | x | call_sensitivity.rb:204:8:204:8 | x | provenance |  |
 | call_sensitivity.rb:207:16:207:16 | y | call_sensitivity.rb:209:9:209:9 | y | provenance |  |
 | call_sensitivity.rb:209:9:209:9 | y | call_sensitivity.rb:214:9:214:9 | x | provenance |  |
 | call_sensitivity.rb:214:9:214:9 | x | call_sensitivity.rb:215:10:215:10 | x | provenance |  |
@@ -169,8 +167,6 @@ nodes
 | call_sensitivity.rb:199:16:199:23 | call to taint | semmle.label | call to taint |
 | call_sensitivity.rb:199:30:199:30 | x | semmle.label | x |
 | call_sensitivity.rb:200:8:200:8 | x | semmle.label | x |
-| call_sensitivity.rb:203:26:203:26 | x | semmle.label | x |
-| call_sensitivity.rb:204:8:204:8 | x | semmle.label | x |
 | call_sensitivity.rb:207:16:207:16 | y | semmle.label | y |
 | call_sensitivity.rb:209:9:209:9 | y | semmle.label | y |
 | call_sensitivity.rb:214:9:214:9 | x | semmle.label | x |
@@ -204,7 +200,6 @@ testFailures
 | call_sensitivity.rb:105:10:105:10 | x | call_sensitivity.rb:178:11:178:19 | call to taint | call_sensitivity.rb:105:10:105:10 | x | $@ | call_sensitivity.rb:178:11:178:19 | call to taint | call to taint |
 | call_sensitivity.rb:105:10:105:10 | x | call_sensitivity.rb:187:12:187:19 | call to taint | call_sensitivity.rb:105:10:105:10 | x | $@ | call_sensitivity.rb:187:12:187:19 | call to taint | call to taint |
 | call_sensitivity.rb:200:8:200:8 | x | call_sensitivity.rb:199:16:199:23 | call to taint | call_sensitivity.rb:200:8:200:8 | x | $@ | call_sensitivity.rb:199:16:199:23 | call to taint | call to taint |
-| call_sensitivity.rb:204:8:204:8 | x | call_sensitivity.rb:199:16:199:23 | call to taint | call_sensitivity.rb:204:8:204:8 | x | $@ | call_sensitivity.rb:199:16:199:23 | call to taint | call to taint |
 | call_sensitivity.rb:215:10:215:10 | x | call_sensitivity.rb:222:16:222:23 | call to taint | call_sensitivity.rb:215:10:215:10 | x | $@ | call_sensitivity.rb:222:16:222:23 | call to taint | call to taint |
 mayBenefitFromCallContext
 | call_sensitivity.rb:6:5:6:21 | call to puts |

ruby/ql/test/library-tests/dataflow/call-sensitivity/call_sensitivity.rb

@@ -201,7 +201,7 @@ def invoke_block2 x
 end
 
 invoke_block2 "safe" do |x|
-  sink x # $ SPURIOUS hasValueFlow=37
+  sink x
 end
 
 def call_m (x, y)

ruby/ql/test/library-tests/dataflow/global/Flow.expected

@@ -5,6 +5,18 @@ edges
 | blocks.rb:18:11:18:11 | x | blocks.rb:24:18:24:18 | x | provenance |  |
 | blocks.rb:24:3:24:11 | call to source | blocks.rb:17:10:17:10 | x | provenance |  |
 | blocks.rb:24:18:24:18 | x | blocks.rb:25:8:25:8 | x | provenance |  |
+| callbacks.rb:9:15:9:15 | x | callbacks.rb:10:12:10:12 | x | provenance |  |
+| callbacks.rb:10:12:10:12 | x | callbacks.rb:17:15:17:15 | x | provenance |  |
+| callbacks.rb:13:20:13:20 | x | callbacks.rb:14:14:14:14 | x | provenance |  |
+| callbacks.rb:14:14:14:14 | x | callbacks.rb:9:15:9:15 | x | provenance |  |
+| callbacks.rb:17:15:17:15 | x | callbacks.rb:17:25:17:25 | x | provenance |  |
+| callbacks.rb:17:31:17:38 | call to taint | callbacks.rb:13:20:13:20 | x | provenance |  |
+| callbacks.rb:20:17:20:17 | x | callbacks.rb:21:11:21:11 | x | provenance |  |
+| callbacks.rb:21:11:21:11 | x | callbacks.rb:28:31:28:31 | x | provenance |  |
+| callbacks.rb:24:23:24:23 | x | callbacks.rb:25:17:25:17 | x | provenance |  |
+| callbacks.rb:25:17:25:17 | x | callbacks.rb:20:17:20:17 | x | provenance |  |
+| callbacks.rb:28:18:28:25 | call to taint | callbacks.rb:24:23:24:23 | x | provenance |  |
+| callbacks.rb:28:31:28:31 | x | callbacks.rb:28:39:28:39 | x | provenance |  |
 | captured_variables.rb:9:24:9:24 | x | captured_variables.rb:11:5:11:6 | fn : [lambda] [captured x] | provenance |  |
 | captured_variables.rb:11:5:11:6 | fn : [lambda] [captured x] | captured_variables.rb:10:20:10:20 | x | provenance |  |
 | captured_variables.rb:13:20:13:29 | call to taint | captured_variables.rb:9:24:9:24 | x | provenance |  |
@@ -272,6 +284,20 @@ nodes
 | blocks.rb:24:3:24:11 | call to source | semmle.label | call to source |
 | blocks.rb:24:18:24:18 | x | semmle.label | x |
 | blocks.rb:25:8:25:8 | x | semmle.label | x |
+| callbacks.rb:9:15:9:15 | x | semmle.label | x |
+| callbacks.rb:10:12:10:12 | x | semmle.label | x |
+| callbacks.rb:13:20:13:20 | x | semmle.label | x |
+| callbacks.rb:14:14:14:14 | x | semmle.label | x |
+| callbacks.rb:17:15:17:15 | x | semmle.label | x |
+| callbacks.rb:17:25:17:25 | x | semmle.label | x |
+| callbacks.rb:17:31:17:38 | call to taint | semmle.label | call to taint |
+| callbacks.rb:20:17:20:17 | x | semmle.label | x |
+| callbacks.rb:21:11:21:11 | x | semmle.label | x |
+| callbacks.rb:24:23:24:23 | x | semmle.label | x |
+| callbacks.rb:25:17:25:17 | x | semmle.label | x |
+| callbacks.rb:28:18:28:25 | call to taint | semmle.label | call to taint |
+| callbacks.rb:28:31:28:31 | x | semmle.label | x |
+| callbacks.rb:28:39:28:39 | x | semmle.label | x |
 | captured_variables.rb:9:24:9:24 | x | semmle.label | x |
 | captured_variables.rb:10:20:10:20 | x | semmle.label | x |
 | captured_variables.rb:11:5:11:6 | fn : [lambda] [captured x] | semmle.label | fn : [lambda] [captured x] |
@@ -585,6 +611,8 @@ testFailures
 #select
 | blocks.rb:8:10:8:14 | yield ... | blocks.rb:14:12:14:20 | call to source | blocks.rb:8:10:8:14 | yield ... | $@ | blocks.rb:14:12:14:20 | call to source | call to source |
 | blocks.rb:25:8:25:8 | x | blocks.rb:24:3:24:11 | call to source | blocks.rb:25:8:25:8 | x | $@ | blocks.rb:24:3:24:11 | call to source | call to source |
+| callbacks.rb:17:25:17:25 | x | callbacks.rb:17:31:17:38 | call to taint | callbacks.rb:17:25:17:25 | x | $@ | callbacks.rb:17:31:17:38 | call to taint | call to taint |
+| callbacks.rb:28:39:28:39 | x | callbacks.rb:28:18:28:25 | call to taint | callbacks.rb:28:39:28:39 | x | $@ | callbacks.rb:28:18:28:25 | call to taint | call to taint |
 | captured_variables.rb:10:20:10:20 | x | captured_variables.rb:13:20:13:29 | call to taint | captured_variables.rb:10:20:10:20 | x | $@ | captured_variables.rb:13:20:13:29 | call to taint | call to taint |
 | captured_variables.rb:17:14:17:14 | x | captured_variables.rb:20:25:20:34 | call to taint | captured_variables.rb:17:14:17:14 | x | $@ | captured_variables.rb:20:25:20:34 | call to taint | call to taint |
 | captured_variables.rb:24:14:24:14 | x | captured_variables.rb:27:48:27:57 | call to taint | captured_variables.rb:24:14:24:14 | x | $@ | captured_variables.rb:27:48:27:57 | call to taint | call to taint |

ruby/ql/test/library-tests/dataflow/global/TypeTrackingInlineTest.expected

@@ -1,4 +1,6 @@
 | blocks.rb:4:10:4:10 | r | Fixed missing result: hasValueFlow=1 |
+| callbacks.rb:17:41:17:58 | # $ hasValueFlow=1 | Missing result: hasValueFlow=1 |
+| callbacks.rb:29:37:29:37 | x | Unexpected result: hasValueFlow=2 |
 | captured_variables.rb:50:10:50:10 | x | Fixed missing result: hasValueFlow=2 |
 | captured_variables.rb:68:25:68:68 | # $ hasValueFlow=3 $ MISSING: hasValueFlow=4 | Missing result: hasValueFlow=3 |
 | captured_variables.rb:72:21:72:66 | # $ hasValueFlow=4 $ SPURIOUS: hasValueFlow=3  | Fixed spurious result: hasValueFlow=3 |

ruby/ql/test/library-tests/dataflow/global/callbacks.rb

@@ -0,0 +1,29 @@
+def taint x
+    x
+end
+
+def sink x
+    puts "SINK: #{x}"
+end
+
+def apply (f, x)
+    f.call(x)
+end
+
+def apply_wrap (f, x)
+    apply(f, x)
+end
+
+apply_wrap(->(x) { sink(x) }, taint(1)) # $ hasValueFlow=1
+apply_wrap(->(x) { sink(x) }, "safe")
+
+def apply_block x
+    yield x
+end
+
+def apply_block_wrap (x, &block)
+    apply_block(x, &block)
+end
+
+apply_block_wrap(taint(2)) { |x| sink(x) } # $ hasValueFlow=2
+apply_block_wrap("safe") { |x| sink(x) }