Swift: Add summaries for tainted URL fields

swift/ql/lib/codeql/swift/dataflow/FlowSteps.qll

@@ -0,0 +1,15 @@
+import swift
+private import codeql.swift.dataflow.DataFlow
+
+/**
+ * A `Content` that should be implicitly regarded as tainted whenever an object with such `Content`
+ * is itself tainted.
+ *
+ * For example, if we had a type `class Container { var field: Contained }`, then by default a tainted
+ * `Container` and a `Container` with a tainted `Contained` stored in its `field` are distinct.
+ *
+ * If `any(DataFlow::FieldContent fc | fc.getField().hasQualifiedName("Container", "field"))` was
+ * included in this type however, then a tainted `Container` would imply that its `field` is also
+ * tainted (but not vice versa).
+ */
+abstract class TaintInheritingContent extends DataFlow::Content { }

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

@@ -2,6 +2,7 @@ private import swift
 private import DataFlowPrivate
 private import TaintTrackingPublic
 private import codeql.swift.dataflow.DataFlow
+private import codeql.swift.dataflow.FlowSteps
 private import codeql.swift.dataflow.Ssa
 private import codeql.swift.controlflow.CfgNodes
 private import FlowSummaryImpl as FlowSummaryImpl
@@ -55,6 +56,12 @@ private module Cached {
       se = nodeTo.asExpr()
     )
     or
+    // flow through the read of a content that inherits taint
+    exists(DataFlow::ContentSet f |
+      readStep(nodeFrom, f, nodeTo) and
+      f.getAReadContent() instanceof TaintInheritingContent
+    )
+    or
     // flow through a flow summary (extension of `SummaryModelCsv`)
     FlowSummaryImpl::Private::Steps::summaryLocalStep(nodeFrom, nodeTo, false)
   }

swift/ql/lib/codeql/swift/frameworks/StandardLibrary/Url.qll

@@ -1,5 +1,19 @@
 import swift
+private import codeql.swift.dataflow.DataFlow
 private import codeql.swift.dataflow.ExternalFlow
+private import codeql.swift.dataflow.FlowSteps
+
+/** The struct `URL`. */
+class UrlDecl extends StructDecl {
+  UrlDecl() { this.getFullName() = "URL" }
+}
+
+/**
+ * A content implying that, if a `URL` is tainted, then all its fields are tainted.
+ */
+private class UriFieldsInheritTaint extends TaintInheritingContent, DataFlow::Content::FieldContent {
+  UriFieldsInheritTaint() { this.getField().getEnclosingDecl() instanceof UrlDecl }
+}
 
 /**
  * A model for `URL` members that are sources of remote flow.

swift/ql/test/library-tests/dataflow/taint/LocalTaint.expected

@@ -125,3 +125,39 @@
 | string.swift:39:29:39:29 | < | string.swift:39:13:39:29 | ... .+(_:_:) ... |
 | subscript.swift:13:10:13:17 | call to source() | subscript.swift:13:10:13:20 | ...[...] |
 | subscript.swift:14:10:14:18 | call to source2() | subscript.swift:14:10:14:21 | ...[...] |
+| url.swift:64:12:64:12 | urlTainted | url.swift:64:12:64:23 | .absoluteURL |
+| url.swift:65:12:65:12 | urlTainted | url.swift:65:12:65:23 | .baseURL |
+| url.swift:66:15:66:15 | urlTainted | url.swift:66:15:66:26 | .fragment |
+| url.swift:67:15:67:15 | urlTainted | url.swift:67:15:67:26 | .host |
+| url.swift:68:15:68:15 | urlTainted | url.swift:68:15:68:26 | .lastPathComponent |
+| url.swift:69:15:69:15 | urlTainted | url.swift:69:15:69:26 | .path |
+| url.swift:70:15:70:15 | urlTainted | url.swift:70:15:70:26 | .pathComponents |
+| url.swift:70:15:70:26 | .pathComponents | url.swift:70:15:70:42 | ...[...] |
+| url.swift:71:15:71:15 | urlTainted | url.swift:71:15:71:26 | .pathExtension |
+| url.swift:72:12:72:12 | urlTainted | url.swift:72:12:72:23 | .port |
+| url.swift:73:15:73:15 | urlTainted | url.swift:73:15:73:26 | .query |
+| url.swift:74:15:74:15 | urlTainted | url.swift:74:15:74:26 | .relativePath |
+| url.swift:75:15:75:15 | urlTainted | url.swift:75:15:75:26 | .relativeString |
+| url.swift:76:15:76:15 | urlTainted | url.swift:76:15:76:26 | .scheme |
+| url.swift:77:12:77:12 | urlTainted | url.swift:77:12:77:23 | .standardized |
+| url.swift:78:12:78:12 | urlTainted | url.swift:78:12:78:23 | .standardizedFileURL |
+| url.swift:79:15:79:15 | urlTainted | url.swift:79:15:79:26 | .user |
+| url.swift:80:15:80:15 | urlTainted | url.swift:80:15:80:26 | .password |
+| url.swift:86:12:86:54 | ...! | url.swift:86:12:86:56 | .absoluteURL |
+| url.swift:87:12:87:54 | ...! | url.swift:87:12:87:56 | .baseURL |
+| url.swift:88:15:88:57 | ...! | url.swift:88:15:88:59 | .fragment |
+| url.swift:89:15:89:57 | ...! | url.swift:89:15:89:59 | .host |
+| url.swift:90:15:90:57 | ...! | url.swift:90:15:90:59 | .lastPathComponent |
+| url.swift:91:15:91:57 | ...! | url.swift:91:15:91:59 | .path |
+| url.swift:92:15:92:57 | ...! | url.swift:92:15:92:59 | .pathComponents |
+| url.swift:92:15:92:59 | .pathComponents | url.swift:92:15:92:75 | ...[...] |
+| url.swift:93:15:93:57 | ...! | url.swift:93:15:93:59 | .pathExtension |
+| url.swift:94:12:94:54 | ...! | url.swift:94:12:94:56 | .port |
+| url.swift:95:15:95:57 | ...! | url.swift:95:15:95:59 | .query |
+| url.swift:96:15:96:57 | ...! | url.swift:96:15:96:59 | .relativePath |
+| url.swift:97:15:97:57 | ...! | url.swift:97:15:97:59 | .relativeString |
+| url.swift:98:15:98:57 | ...! | url.swift:98:15:98:59 | .scheme |
+| url.swift:99:12:99:54 | ...! | url.swift:99:12:99:56 | .standardized |
+| url.swift:100:12:100:54 | ...! | url.swift:100:12:100:56 | .standardizedFileURL |
+| url.swift:101:15:101:57 | ...! | url.swift:101:15:101:59 | .user |
+| url.swift:102:15:102:57 | ...! | url.swift:102:15:102:59 | .password |