Shared: Add shared concepts library

shared/concepts/codeql/concepts/internal/SensitiveDataHeuristics.qll

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+/**
+ * INTERNAL: Do not use.
+ *
+ * Provides classes and predicates for identifying strings that may indicate the presence of sensitive data.
+ * Such that we can share this logic across our CodeQL analysis of different languages.
+ *
+ * 'Sensitive' data in general is anything that should not be sent around in unencrypted form.
+ */
+
+/**
+ * A classification of different kinds of sensitive data:
+ *
+ *   - secret: generic secret or trusted data;
+ *   - id: a user name or other account information;
+ *   - password: a password or authorization key;
+ *   - certificate: a certificate.
+ *   - private: private data such as credit card numbers
+ *
+ * While classifications are represented as strings, this should not be relied upon.
+ * Instead, use the predicates in `SensitiveDataClassification::` to work with
+ * classifications.
+ */
+class SensitiveDataClassification extends string {
+  SensitiveDataClassification() { this in ["secret", "id", "password", "certificate", "private"] }
+}
+
+/**
+ * Provides predicates to select the different kinds of sensitive data we support.
+ */
+module SensitiveDataClassification {
+  /** Gets the classification for secret or trusted data. */
+  SensitiveDataClassification secret() { result = "secret" }
+
+  /** Gets the classification for user names or other account information. */
+  SensitiveDataClassification id() { result = "id" }
+
+  /** Gets the classification for passwords or authorization keys. */
+  SensitiveDataClassification password() { result = "password" }
+
+  /** Gets the classification for certificates. */
+  SensitiveDataClassification certificate() { result = "certificate" }
+
+  /** Gets the classification for private data. */
+  SensitiveDataClassification private() { result = "private" }
+}
+
+/**
+ * INTERNAL: Do not use.
+ *
+ * Provides heuristics for identifying names related to sensitive information.
+ */
+module HeuristicNames {
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence of secret
+   * or trusted data.
+   */
+  string maybeSecret() { result = "(?is).*((?<!is|is_)secret|(?<!un|un_|is|is_)trusted).*" }
+
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence of
+   * user names or other account information.
+   */
+  string maybeAccountInfo() {
+    result = "(?is).*acc(ou)?nt.*" or
+    result = "(?is).*(puid|user.?name|user.?id|session.?(id|key)).*" or
+    result = "(?s).*([uU]|^|_|[a-z](?=U))([uU][iI][dD]).*"
+  }
+
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence of
+   * a password or an authorization key.
+   */
+  string maybePassword() {
+    result = "(?is).*pass(wd|word|code|.?phrase)(?!.*question).*" or
+    result = "(?is).*(auth(entication|ori[sz]ation)?).?key.*"
+  }
+
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence of
+   * a certificate.
+   */
+  string maybeCertificate() { result = "(?is).*(cert)(?!.*(format|name|ification)).*" }
+
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence of
+   * private data.
+   */
+  string maybePrivate() {
+    result =
+      "(?is).*(" +
+        // Inspired by the list on https://cwe.mitre.org/data/definitions/359.html
+        // Government identifiers, such as Social Security Numbers
+        "social.?security|employer.?identification|national.?insurance|resident.?id|" +
+        "passport.?(num|no)|([_-]|\\b)ssn([_-]|\\b)|" +
+        // Contact information, such as home addresses
+        "post.?code|zip.?code|home.?addr|" +
+        // and telephone numbers
+        "(mob(ile)?|home).?(num|no|tel|phone)|(tel|fax|phone).?(num|no)|telephone|" +
+        "emergency.?contact|" +
+        // Geographic location - where the user is (or was)
+        "latitude|longitude|nationality|" +
+        // Financial data - such as credit card numbers, salary, bank accounts, and debts
+        "(credit|debit|bank|visa).?(card|num|no|acc(ou)?nt)|acc(ou)?nt.?(no|num|credit)|" +
+        "salary|billing|credit.?(rating|score)|([_-]|\\b)ccn([_-]|\\b)|" +
+        // Communications - e-mail addresses, private e-mail messages, SMS text messages, chat logs, etc.
+        // "e(mail|_mail)|" + // this seems too noisy
+        // Health - medical conditions, insurance status, prescription records
+        "birth.?da(te|y)|da(te|y).?(of.?)?birth|" +
+        "medical|(health|care).?plan|healthkit|appointment|prescription|" +
+        "blood.?(type|alcohol|glucose|pressure)|heart.?(rate|rhythm)|body.?(mass|fat)|" +
+        "menstrua|pregnan|insulin|inhaler|" +
+        // Relationships - work and family
+        "employ(er|ee)|spouse|maiden.?name" +
+        // ---
+        ").*"
+  }
+
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence
+   * of sensitive data, with `classification` describing the kind of sensitive data involved.
+   */
+  string maybeSensitiveRegexp(SensitiveDataClassification classification) {
+    result = maybeSecret() and classification = SensitiveDataClassification::secret()
+    or
+    result = maybeAccountInfo() and classification = SensitiveDataClassification::id()
+    or
+    result = maybePassword() and classification = SensitiveDataClassification::password()
+    or
+    result = maybeCertificate() and
+    classification = SensitiveDataClassification::certificate()
+    or
+    result = maybePrivate() and
+    classification = SensitiveDataClassification::private()
+  }
+
+  /**
+   * Gets a regular expression that identifies strings that may indicate the presence of data
+   * that is hashed or encrypted, and hence rendered non-sensitive, or contains special characters
+   * suggesting nouns within the string do not represent the meaning of the whole string (e.g. a URL or a SQL query).
+   *
+   * We also filter out common words like `certain` and `concert`, since otherwise these could
+   * be matched by the certificate regular expressions. Same for `accountable` (account), or
+   * `secretarial` (secret).
+   */
+  string notSensitiveRegexp() {
+    result =
+      "(?is).*([^\\w$.-]|redact|censor|obfuscate|hash|md5|sha|random|((?<!un)(en))?(crypt|(?<!pass)code)|certain|concert|secretar|accountant|accountab).*"
+  }
+
+  /**
+   * Holds if `name` may indicate the presence of sensitive data, and `name` does not indicate that
+   * the data is in fact non-sensitive (for example since it is hashed or encrypted).
+   *
+   * That is, one of the regexps from `maybeSensitiveRegexp` matches `name` (with the given
+   * classification), and none of the regexps from `notSensitiveRegexp` matches `name`.
+   */
+  bindingset[name]
+  predicate nameIndicatesSensitiveData(string name) {
+    exists(string combinedRegexp |
+      // Combine all the maybe-sensitive regexps into one using non-capturing groups and |.
+      combinedRegexp =
+        "(?:" + strictconcat(string r | r = maybeSensitiveRegexp(_) | r, ")|(?:") + ")"
+    |
+      name.regexpMatch(combinedRegexp)
+    ) and
+    not name.regexpMatch(notSensitiveRegexp())
+  }
+
+  /**
+   * Holds if `name` may indicate the presence of sensitive data, and
+   * `name` does not indicate that the data is in fact non-sensitive (for example since
+   * it is hashed or encrypted). `classification` describes the kind of sensitive data
+   * involved.
+   *
+   * That is, one of the regexps from `maybeSensitiveRegexp` matches `name` (with the
+   * given classification), and none of the regexps from `notSensitiveRegexp` matches
+   * `name`.
+   *
+   * When the set of names is large, it's worth using `nameIndicatesSensitiveData/1` as a first
+   * pass, since that combines all the regexps into one, and should be faster. Then call this
+   * predicate to get the classification(s).
+   */
+  bindingset[name]
+  predicate nameIndicatesSensitiveData(string name, SensitiveDataClassification classification) {
+    name.regexpMatch(maybeSensitiveRegexp(classification)) and
+    not name.regexpMatch(notSensitiveRegexp())
+  }
+}

shared/concepts/qlpack.yml

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+name: codeql/concepts
+version: 0.0.0-dev
+groups: shared
+library: true
+dependencies: null
+warnOnImplicitThis: true