Python: Remove usernames as sensitive source for cleartext queries

Closes github#6363, github#6927, github#6726, github#7497, github#7116

Author: RasmusWL

python/ql/lib/semmle/python/security/dataflow/CleartextLoggingCustomizations.qll

@@ -40,6 +40,10 @@ module CleartextLogging {
    * A source of sensitive data, considered as a flow source.
    */
   class SensitiveDataSourceAsSource extends Source, SensitiveDataSource {
+    SensitiveDataSourceAsSource() {
+      not SensitiveDataSource.super.getClassification() = SensitiveDataClassification::id()
+    }
+
     override SensitiveDataClassification getClassification() {
       result = SensitiveDataSource.super.getClassification()
     }

python/ql/lib/semmle/python/security/dataflow/CleartextStorageCustomizations.qll

@@ -39,6 +39,10 @@ module CleartextStorage {
    * A source of sensitive data, considered as a flow source.
    */
   class SensitiveDataSourceAsSource extends Source, SensitiveDataSource {
+    SensitiveDataSourceAsSource() {
+      not SensitiveDataSource.super.getClassification() = SensitiveDataClassification::id()
+    }
+
     override SensitiveDataClassification getClassification() {
       result = SensitiveDataSource.super.getClassification()
     }

python/ql/src/change-notes/2021-01-19-remove-cleartext-fps.md

@@ -0,0 +1,4 @@
+---
+category: majorAnalysis
+---
+* No longer consider usernames or other account information as sensitive data for the queries `py/clear-text-logging-sensitive-data` and `py/clear-text-storage-sensitive-data`, since this has lead to many false positives.

python/ql/test/query-tests/Security/CWE-312-CleartextLogging/CleartextLogging.expected

@@ -4,9 +4,6 @@ edges
 | test.py:19:16:19:29 | ControlFlowNode for get_password() | test.py:23:58:23:65 | ControlFlowNode for password |
 | test.py:19:16:19:29 | ControlFlowNode for get_password() | test.py:27:40:27:47 | ControlFlowNode for password |
 | test.py:19:16:19:29 | ControlFlowNode for get_password() | test.py:30:58:30:65 | ControlFlowNode for password |
-| test.py:43:9:43:15 | ControlFlowNode for account | test.py:46:11:46:17 | ControlFlowNode for account |
-| test.py:43:18:43:27 | ControlFlowNode for account_id | test.py:50:18:50:51 | ControlFlowNode for Fstring |
-| test.py:55:9:55:24 | ControlFlowNode for generate_uuid4() | test.py:56:11:56:11 | ControlFlowNode for x |
 | test.py:65:14:68:5 | ControlFlowNode for Dict | test.py:69:11:69:31 | ControlFlowNode for Subscript |
 | test.py:67:21:67:37 | ControlFlowNode for Attribute | test.py:65:14:68:5 | ControlFlowNode for Dict |
 nodes
@@ -20,13 +17,6 @@ nodes
 | test.py:37:11:37:24 | ControlFlowNode for get_password() | semmle.label | ControlFlowNode for get_password() |
 | test.py:39:22:39:35 | ControlFlowNode for get_password() | semmle.label | ControlFlowNode for get_password() |
 | test.py:40:22:40:35 | ControlFlowNode for get_password() | semmle.label | ControlFlowNode for get_password() |
-| test.py:43:9:43:15 | ControlFlowNode for account | semmle.label | ControlFlowNode for account |
-| test.py:43:18:43:27 | ControlFlowNode for account_id | semmle.label | ControlFlowNode for account_id |
-| test.py:46:11:46:17 | ControlFlowNode for account | semmle.label | ControlFlowNode for account |
-| test.py:50:18:50:51 | ControlFlowNode for Fstring | semmle.label | ControlFlowNode for Fstring |
-| test.py:55:9:55:24 | ControlFlowNode for generate_uuid4() | semmle.label | ControlFlowNode for generate_uuid4() |
-| test.py:56:11:56:11 | ControlFlowNode for x | semmle.label | ControlFlowNode for x |
-| test.py:60:50:60:70 | ControlFlowNode for Attribute | semmle.label | ControlFlowNode for Attribute |
 | test.py:65:14:68:5 | ControlFlowNode for Dict | semmle.label | ControlFlowNode for Dict |
 | test.py:67:21:67:37 | ControlFlowNode for Attribute | semmle.label | ControlFlowNode for Attribute |
 | test.py:69:11:69:31 | ControlFlowNode for Subscript | semmle.label | ControlFlowNode for Subscript |
@@ -41,8 +31,4 @@ subpaths
 | test.py:37:11:37:24 | ControlFlowNode for get_password() | test.py:37:11:37:24 | ControlFlowNode for get_password() | test.py:37:11:37:24 | ControlFlowNode for get_password() | $@ is logged here. | test.py:37:11:37:24 | ControlFlowNode for get_password() | Sensitive data (password) |
 | test.py:39:22:39:35 | ControlFlowNode for get_password() | test.py:39:22:39:35 | ControlFlowNode for get_password() | test.py:39:22:39:35 | ControlFlowNode for get_password() | $@ is logged here. | test.py:39:22:39:35 | ControlFlowNode for get_password() | Sensitive data (password) |
 | test.py:40:22:40:35 | ControlFlowNode for get_password() | test.py:40:22:40:35 | ControlFlowNode for get_password() | test.py:40:22:40:35 | ControlFlowNode for get_password() | $@ is logged here. | test.py:40:22:40:35 | ControlFlowNode for get_password() | Sensitive data (password) |
-| test.py:46:11:46:17 | ControlFlowNode for account | test.py:43:9:43:15 | ControlFlowNode for account | test.py:46:11:46:17 | ControlFlowNode for account | $@ is logged here. | test.py:43:9:43:15 | ControlFlowNode for account | Sensitive data (id) |
-| test.py:50:18:50:51 | ControlFlowNode for Fstring | test.py:43:18:43:27 | ControlFlowNode for account_id | test.py:50:18:50:51 | ControlFlowNode for Fstring | $@ is logged here. | test.py:43:18:43:27 | ControlFlowNode for account_id | Sensitive data (id) |
-| test.py:56:11:56:11 | ControlFlowNode for x | test.py:55:9:55:24 | ControlFlowNode for generate_uuid4() | test.py:56:11:56:11 | ControlFlowNode for x | $@ is logged here. | test.py:55:9:55:24 | ControlFlowNode for generate_uuid4() | Sensitive data (id) |
-| test.py:60:50:60:70 | ControlFlowNode for Attribute | test.py:60:50:60:70 | ControlFlowNode for Attribute | test.py:60:50:60:70 | ControlFlowNode for Attribute | $@ is logged here. | test.py:60:50:60:70 | ControlFlowNode for Attribute | Sensitive data (id) |
 | test.py:69:11:69:31 | ControlFlowNode for Subscript | test.py:67:21:67:37 | ControlFlowNode for Attribute | test.py:69:11:69:31 | ControlFlowNode for Subscript | $@ is logged here. | test.py:67:21:67:37 | ControlFlowNode for Attribute | Sensitive data (password) |

python/ql/test/query-tests/Security/CWE-312-CleartextStorage/CleartextStorage.expected

@@ -4,7 +4,6 @@ edges
 | test.py:6:12:6:21 | ControlFlowNode for get_cert() | test.py:8:20:8:23 | ControlFlowNode for cert |
 | test.py:6:12:6:21 | ControlFlowNode for get_cert() | test.py:9:17:9:29 | ControlFlowNode for List |
 | test.py:9:17:9:29 | ControlFlowNode for List | test.py:10:25:10:29 | ControlFlowNode for lines |
-| test.py:20:13:20:28 | ControlFlowNode for generate_uuid4() | test.py:21:20:21:20 | ControlFlowNode for x |
 nodes
 | password_in_cookie.py:7:16:7:43 | ControlFlowNode for Attribute() | semmle.label | ControlFlowNode for Attribute() |
 | password_in_cookie.py:9:33:9:40 | ControlFlowNode for password | semmle.label | ControlFlowNode for password |
@@ -14,12 +13,9 @@ nodes
 | test.py:8:20:8:23 | ControlFlowNode for cert | semmle.label | ControlFlowNode for cert |
 | test.py:9:17:9:29 | ControlFlowNode for List | semmle.label | ControlFlowNode for List |
 | test.py:10:25:10:29 | ControlFlowNode for lines | semmle.label | ControlFlowNode for lines |
-| test.py:20:13:20:28 | ControlFlowNode for generate_uuid4() | semmle.label | ControlFlowNode for generate_uuid4() |
-| test.py:21:20:21:20 | ControlFlowNode for x | semmle.label | ControlFlowNode for x |
 subpaths
 #select
 | password_in_cookie.py:9:33:9:40 | ControlFlowNode for password | password_in_cookie.py:7:16:7:43 | ControlFlowNode for Attribute() | password_in_cookie.py:9:33:9:40 | ControlFlowNode for password | $@ is stored here. | password_in_cookie.py:7:16:7:43 | ControlFlowNode for Attribute() | Sensitive data (password) |
 | password_in_cookie.py:16:33:16:40 | ControlFlowNode for password | password_in_cookie.py:14:16:14:43 | ControlFlowNode for Attribute() | password_in_cookie.py:16:33:16:40 | ControlFlowNode for password | $@ is stored here. | password_in_cookie.py:14:16:14:43 | ControlFlowNode for Attribute() | Sensitive data (password) |
 | test.py:8:20:8:23 | ControlFlowNode for cert | test.py:6:12:6:21 | ControlFlowNode for get_cert() | test.py:8:20:8:23 | ControlFlowNode for cert | $@ is stored here. | test.py:6:12:6:21 | ControlFlowNode for get_cert() | Sensitive data (certificate) |
 | test.py:10:25:10:29 | ControlFlowNode for lines | test.py:6:12:6:21 | ControlFlowNode for get_cert() | test.py:10:25:10:29 | ControlFlowNode for lines | $@ is stored here. | test.py:6:12:6:21 | ControlFlowNode for get_cert() | Sensitive data (certificate) |
-| test.py:21:20:21:20 | ControlFlowNode for x | test.py:20:13:20:28 | ControlFlowNode for generate_uuid4() | test.py:21:20:21:20 | ControlFlowNode for x | $@ is stored here. | test.py:20:13:20:28 | ControlFlowNode for generate_uuid4() | Sensitive data (id) |