Merge pull request #8581 from tausbn/python-fix-bad-join-in-import_star_read

yoff · web-flow · commit 7efb4ab4e4a4 · 2022-04-29T13:14:14.000+02:00
Python: Fix bad join in `import_star_read`
diff --git a/python/ql/lib/semmle/python/Exprs.qll b/python/ql/lib/semmle/python/Exprs.qll
@@ -189,7 +189,16 @@ class Call extends Call_ {
    */
   Keyword getKeyword(int index) {
     result = this.getNamedArg(index) and
-    not exists(DictUnpacking d, int lower | d = this.getNamedArg(lower) and lower < index)
+    (
+      not exists(this.getMinimumUnpackingIndex())
+      or
+      index <= this.getMinimumUnpackingIndex()
+    )
+  }
+
+  /** Gets the minimum index (if any) at which a dictionary unpacking (`**foo`) occurs in this call. */
+  private int getMinimumUnpackingIndex() {
+    result = min(int i | this.getNamedArg(i) instanceof DictUnpacking)
   }
 
   /**
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll
@@ -401,8 +401,15 @@ class ModuleVariableNode extends Node, TModuleVariableNode {
 private predicate isAccessedThroughImportStar(Module m) { m = ImportStar::getStarImported(_) }
 
 private ModuleVariableNode import_star_read(Node n) {
-  ImportStar::importStarResolvesTo(n.asCfgNode(), result.getModule()) and
-  n.asCfgNode().(NameNode).getId() = result.getVariable().getId()
+  resolved_import_star_module(result.getModule(), result.getVariable().getId(), n)
+}
+
+pragma[nomagic]
+private predicate resolved_import_star_module(Module m, string name, Node n) {
+  exists(NameNode nn | nn = n.asCfgNode() |
+    ImportStar::importStarResolvesTo(pragma[only_bind_into](nn), m) and
+    nn.getId() = name
+  )
 }
 
 /**
diff --git a/python/ql/lib/semmle/python/pointsto/PointsTo.qll b/python/ql/lib/semmle/python/pointsto/PointsTo.qll
@@ -2129,7 +2129,7 @@ module Conditionals {
 /** INTERNAL: Do not use. */
 predicate declaredAttributeVar(PythonClassObjectInternal cls, string name, EssaVariable var) {
   name = var.getName() and
-  var.getAUse() = cls.getScope().getANormalExit()
+  pragma[only_bind_into](pragma[only_bind_into](var).getAUse()) = cls.getScope().getANormalExit()
 }
 
 cached

Original file line number	Diff line number	Diff line change
`@@ -2129,7 +2129,7 @@ module Conditionals {`
`2129`	`2129`	`/** INTERNAL: Do not use. */`
`2130`	`2130`	`predicate declaredAttributeVar(PythonClassObjectInternal cls, string name, EssaVariable var) {`
`2131`	`2131`	`name = var.getName() and`
`2132`		`- var.getAUse() = cls.getScope().getANormalExit()`
	`2132`	`+ pragma[only_bind_into](pragma[only_bind_into](var).getAUse()) = cls.getScope().getANormalExit()`
`2133`	`2133`	`}`
`2134`	`2134`
`2135`	`2135`	`cached`