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Merge pull request #11590 from atorralba/atorralba/swift/sensitive-info-logs
Swift: Add Cleartext Logging query
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‎swift/ql/lib/codeql/swift/dataflow/ExternalFlow.qll‎

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@@ -89,6 +89,7 @@ private module Frameworks {
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private import codeql.swift.frameworks.StandardLibrary.UrlSession
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private import codeql.swift.frameworks.StandardLibrary.WebView
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private import codeql.swift.frameworks.Alamofire.Alamofire
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private import codeql.swift.security.CleartextLogging
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private import codeql.swift.security.PathInjection
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private import codeql.swift.security.PredicateInjection
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}

‎swift/ql/lib/codeql/swift/security/CleartextLogging.qll‎

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/** Provides classes and predicates to reason about cleartext logging of sensitive data vulnerabilities. */
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import swift
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private import codeql.swift.dataflow.DataFlow
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private import codeql.swift.dataflow.ExternalFlow
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private import codeql.swift.security.SensitiveExprs
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/** A data flow sink for cleartext logging of sensitive data vulnerabilities. */
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abstract class CleartextLoggingSink extends DataFlow::Node { }
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/** A sanitizer for cleartext logging of sensitive data vulnerabilities. */
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abstract class CleartextLoggingSanitizer extends DataFlow::Node { }
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/**
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* A unit class for adding additional taint steps.
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*
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* Extend this class to add additional taint steps that should apply to paths related to
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* cleartext logging of sensitive data vulnerabilities.
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*/
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class CleartextLoggingAdditionalTaintStep extends Unit {
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/**
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* Holds if the step from `n1` to `n2` should be considered a taint
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* step for flows related to cleartext logging of sensitive data vulnerabilities.
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*/
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abstract predicate step(DataFlow::Node n1, DataFlow::Node n2);
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}
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private class DefaultCleartextLoggingSink extends CleartextLoggingSink {
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DefaultCleartextLoggingSink() { sinkNode(this, "logging") }
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}
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/**
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* A sanitizer for `OSLogMessage`s configured with the appropriate privacy option.
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* Numeric and boolean arguments aren't redacted unless the `private` or `sensitive` options are used.
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* Arguments of other types are always redacted unless the `public` option is used.
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*/
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private class OsLogPrivacyCleartextLoggingSanitizer extends CleartextLoggingSanitizer {
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OsLogPrivacyCleartextLoggingSanitizer() {
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exists(CallExpr c, AutoClosureExpr e |
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c.getStaticTarget().getName().matches("appendInterpolation(_:%privacy:%)") and
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c.getArgument(0).getExpr() = e and
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this.asExpr() = e
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|
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e.getExpr().getType() instanceof OsLogNonRedactedType and
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c.getArgumentWithLabel("privacy").getExpr().(OsLogPrivacyRef).isSafe()
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or
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not e.getExpr().getType() instanceof OsLogNonRedactedType and
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not c.getArgumentWithLabel("privacy").getExpr().(OsLogPrivacyRef).isPublic()
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)
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}
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}
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/** A type that isn't redacted by default in an `OSLogMessage`. */
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private class OsLogNonRedactedType extends Type {
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OsLogNonRedactedType() {
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this.getName() = [["", "U"] + "Int" + ["", "8", "16", "32", "64"], "Double", "Float", "Bool"]
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}
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}
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/** A reference to a field of `OsLogPrivacy`. */
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private class OsLogPrivacyRef extends MemberRefExpr {
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string optionName;
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OsLogPrivacyRef() {
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exists(FieldDecl f | this.getMember() = f |
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f.getEnclosingDecl().(NominalTypeDecl).getName() = "OSLogPrivacy" and
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optionName = f.getName()
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)
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}
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/** Holds if this is a safe privacy option (private or sensitive). */
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predicate isSafe() { optionName = ["private", "sensitive"] }
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/** Holds if this is a public (that is, unsafe) privacy option. */
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predicate isPublic() { optionName = "public" }
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}
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private class LoggingSinks extends SinkModelCsv {
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override predicate row(string row) {
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row =
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[
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";;false;print(_:separator:terminator:);;;Argument[0].ArrayElement;logging",
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";;false;print(_:separator:terminator:);;;Argument[1..2];logging",
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";;false;print(_:separator:terminator:toStream:);;;Argument[0].ArrayElement;logging",
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";;false;print(_:separator:terminator:toStream:);;;Argument[1..2];logging",
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";;false;NSLog(_:_:);;;Argument[0];logging",
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";;false;NSLog(_:_:);;;Argument[1].ArrayElement;logging",
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";;false;NSLogv(_:_:);;;Argument[0];logging",
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";;false;NSLogv(_:_:);;;Argument[1].ArrayElement;logging",
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";;false;vfprintf(_:_:_:);;;Agument[1..2];logging",
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";Logger;true;log(_:);;;Argument[0];logging",
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";Logger;true;log(level:_:);;;Argument[1];logging",
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";Logger;true;trace(_:);;;Argument[1];logging",
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";Logger;true;debug(_:);;;Argument[1];logging",
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";Logger;true;info(_:);;;Argument[1];logging",
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";Logger;true;notice(_:);;;Argument[1];logging",
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";Logger;true;warning(_:);;;Argument[1];logging",
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";Logger;true;error(_:);;;Argument[1];logging",
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";Logger;true;critical(_:);;;Argument[1];logging",
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";Logger;true;fault(_:);;;Argument[1];logging",
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]
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}
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}

‎swift/ql/lib/codeql/swift/security/CleartextLoggingQuery.qll‎

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/**
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* Provides a taint-tracking configuration for reasoning about cleartext logging of
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* sensitive data vulnerabilities.
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*/
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import swift
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private import codeql.swift.dataflow.DataFlow
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private import codeql.swift.dataflow.TaintTracking
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private import codeql.swift.security.CleartextLogging
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private import codeql.swift.security.SensitiveExprs
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/**
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* A taint-tracking configuration for cleartext logging of sensitive data vulnerabilities.
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*/
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class CleartextLoggingConfiguration extends TaintTracking::Configuration {
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CleartextLoggingConfiguration() { this = "CleartextLoggingConfiguration" }
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override predicate isSource(DataFlow::Node source) { source.asExpr() instanceof SensitiveExpr }
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override predicate isSink(DataFlow::Node sink) { sink instanceof CleartextLoggingSink }
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override predicate isSanitizer(DataFlow::Node sanitizer) {
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sanitizer instanceof CleartextLoggingSanitizer
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}
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// Disregard paths that contain other paths. This helps with performance.
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override predicate isSanitizerIn(DataFlow::Node node) { this.isSource(node) }
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override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
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any(CleartextLoggingAdditionalTaintStep s).step(n1, n2)
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}
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}

‎swift/ql/src/queries/Security/CWE-312/CleartextLogging.qhelp‎

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<!DOCTYPE qhelp PUBLIC
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"-//Semmle//qhelp//EN"
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"qhelp.dtd">
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<qhelp>
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<overview>
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<p>
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Attackers could gain access to sensitive information that is logged unencrypted.
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</p>
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</overview>
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<recommendation>
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<p>
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Always make sure to encrypt or obfuscate sensitive information before you log it.
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</p>
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<p>
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Generally, you should decrypt sensitive information only at the point where it is necessary for it to be used in cleartext.
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</p>
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<p>
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Be aware that external processes often store the standard output and
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standard error streams of the application. This will include logged sensitive information.
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</p>
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</recommendation>
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<example>
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<p>
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The following example code logs user credentials (in this case, their password)
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in plaintext:
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</p>
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<sample src="CleartextLoggingBad.swift"/>
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<p>
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Instead, you should encrypt or obfuscate the credentials, or omit them entirely:
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</p>
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<sample src="CleartextLoggingGood.swift"/>
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</example>
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<references>
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<li>M. Dowd, J. McDonald and J. Schuhm, <i>The Art of Software Security Assessment</i>, 1st Edition, Chapter 2 - 'Common Vulnerabilities of Encryption', p. 43. Addison Wesley, 2006.</li>
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<li>M. Howard and D. LeBlanc, <i>Writing Secure Code</i>, 2nd Edition, Chapter 9 - 'Protecting Secret Data', p. 299. Microsoft, 2002.</li>
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<li>OWASP: <a href="https://www.owasp.org/index.php/Password_Plaintext_Storage">Password Plaintext Storage</a>.</li>
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</references>
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</qhelp>

‎swift/ql/src/queries/Security/CWE-312/CleartextLogging.ql‎

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/**
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* @name Cleartext logging of sensitive information
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* @description Logging sensitive information in plaintext can
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* expose it to an attacker.
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* @kind path-problem
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* @problem.severity error
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* @security-severity 7.5
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* @precision high
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* @id swift/clear-text-logging
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* @tags security
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* external/cwe/cwe-312
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* external/cwe/cwe-359
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* external/cwe/cwe-532
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*/
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import swift
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import codeql.swift.dataflow.DataFlow
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import codeql.swift.security.CleartextLoggingQuery
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import DataFlow::PathGraph
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from DataFlow::PathNode src, DataFlow::PathNode sink
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where any(CleartextLoggingConfiguration c).hasFlowPath(src, sink)
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select sink.getNode(), src, sink, "This $@ is written to a log file.", src.getNode(),
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"potentially sensitive information"

‎swift/ql/src/queries/Security/CWE-312/CleartextLoggingBad.swift‎

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let password = "P@ssw0rd"
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NSLog("User password changed to \(password)")

‎swift/ql/src/queries/Security/CWE-312/CleartextLoggingGood.swift‎

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let password = "P@ssw0rd"
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NSLog("User password changed")

‎swift/ql/test/query-tests/Security/CWE-312/CleartextLoggingTest.expected‎

Whitespace-only changes.

‎swift/ql/test/query-tests/Security/CWE-312/CleartextLoggingTest.ql‎

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import swift
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import codeql.swift.dataflow.DataFlow
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import codeql.swift.security.CleartextLoggingQuery
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import TestUtilities.InlineExpectationsTest
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class CleartextLogging extends InlineExpectationsTest {
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CleartextLogging() { this = "CleartextLogging" }
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override string getARelevantTag() { result = "hasCleartextLogging" }
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override predicate hasActualResult(Location location, string element, string tag, string value) {
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exists(
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CleartextLoggingConfiguration config, DataFlow::Node source, DataFlow::Node sink,
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Expr sinkExpr
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|
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config.hasFlow(source, sink) and
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sinkExpr = sink.asExpr() and
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location = sinkExpr.getLocation() and
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element = sinkExpr.toString() and
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tag = "hasCleartextLogging" and
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value = source.asExpr().getLocation().getStartLine().toString()
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)
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}
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}

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