Swift: Add query tests.

Author: geoffw0

swift/ql/test/query-tests/Security/CWE-1333/ReDoS.expected

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+| ReDoS.swift:65:22:65:22 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| ReDoS.swift:66:22:66:22 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| ReDoS.swift:69:18:69:18 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| ReDoS.swift:77:57:77:57 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| ReDoS.swift:80:57:80:57 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |

swift/ql/test/query-tests/Security/CWE-1333/ReDoS.qlref

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+queries/Security/CWE-1333/ReDoS.ql

swift/ql/test/query-tests/Security/CWE-1333/ReDoS.swift

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+
+// --- stubs ---
+
+struct URL {
+	init?(string: String) {}
+}
+
+struct AnyRegexOutput {
+}
+
+protocol RegexComponent {
+}
+
+struct Regex<Output> : RegexComponent {
+	struct Match {
+	}
+
+	init(_ pattern: String) throws where Output == AnyRegexOutput { }
+
+	func firstMatch(in string: String) throws -> Regex<Output>.Match? { return nil}
+
+	typealias RegexOutput = Output
+}
+
+extension String {
+	init(contentsOf: URL) {
+        let data = ""
+        self.init(data)
+    }
+}
+
+class NSObject {
+}
+
+struct _NSRange {
+	init(location: Int, length: Int) { }
+}
+
+typealias NSRange = _NSRange
+
+class NSRegularExpression : NSObject {
+	struct Options : OptionSet {
+	    var rawValue: UInt
+	}
+
+	struct MatchingOptions : OptionSet {
+	    var rawValue: UInt
+	}
+
+	init(pattern: String, options: NSRegularExpression.Options = []) throws { }
+
+	func stringByReplacingMatches(in string: String, options: NSRegularExpression.MatchingOptions = [], range: NSRange, withTemplate templ: String) -> String { return "" }
+}
+
+// --- tests ---
+
+func myRegexpTests(myUrl: URL) throws {
+    let tainted = String(contentsOf: myUrl) // tainted
+    let untainted = "abcdef"
+
+    // Regex
+
+    _ = "((a*)*b)" // GOOD (never used)
+    _ = try Regex("((a*)*b)") // DUBIOUS (never used)
+    _ = try Regex("((a*)*b)").firstMatch(in: untainted) // DUBIOUS (never used on tainted input) [FLAGGED]
+    _ = try Regex("((a*)*b)").firstMatch(in: tainted) // BAD
+    _ = try Regex(".*").firstMatch(in: tainted) // GOOD (safe regex)
+
+    let str = "((a*)*b)" // BAD
+    let regex = try Regex(str)
+    _ = try regex.firstMatch(in: tainted)
+
+    // NSRegularExpression
+
+    _ = try? NSRegularExpression(pattern: "((a*)*b)") // DUBIOUS (never used)
+
+    let nsregex1 = try? NSRegularExpression(pattern: "((a*)*b)") // DUBIOUS (never used on tainted input) [FLAGGED]
+    _ = nsregex1?.stringByReplacingMatches(in: untainted, range: NSRange(location: 0, length: untainted.utf16.count), withTemplate: "")
+
+    let nsregex2 = try? NSRegularExpression(pattern: "((a*)*b)") // BAD
+    _ = nsregex2?.stringByReplacingMatches(in: tainted, range: NSRange(location: 0, length: tainted.utf16.count), withTemplate: "")
+
+    let nsregex3 = try? NSRegularExpression(pattern: ".*") // GOOD (safe regex)
+    _ = nsregex3?.stringByReplacingMatches(in: tainted, range: NSRange(location: 0, length: tainted.utf16.count), withTemplate: "")
+}