Ruby: add YAML.load_file as an unsafe deserialization sink

Author: alexrford

ruby/ql/lib/change-notes/2022-09-23-yaml-load-file.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Added `YAML.load_file` as a potential sink for unsafe deserialization.

ruby/ql/lib/codeql/ruby/security/UnsafeDeserializationCustomizations.qll

@@ -48,12 +48,15 @@ module UnsafeDeserialization {
   }
 
   /**
-   * An argument in a call to `YAML.load`, considered a sink for unsafe
-   * deserialization.
+   * An argument in a call to `YAML.load` or `YAML.load_file`, considered a sink
+   * for unsafe deserialization. As the `YAML` module is an alias of `Psych` in
    */
   class YamlLoadArgument extends Sink {
     YamlLoadArgument() {
-      this = API::getTopLevelMember("YAML").getAMethodCall("load").getArgument(0)
+      this =
+        API::getTopLevelMember(["YAML", "Psych"])
+            .getAMethodCall(["load", "load_file"])
+            .getArgument(0)
     }
   }
 

ruby/ql/test/query-tests/security/cwe-502/unsafe-deserialization/UnsafeDeserialization.expected

@@ -16,6 +16,12 @@ edges
 | UnsafeDeserialization.rb:58:17:58:28 | ...[...] :  | UnsafeDeserialization.rb:68:23:68:31 | json_data |
 | UnsafeDeserialization.rb:80:11:80:16 | call to params :  | UnsafeDeserialization.rb:80:11:80:22 | ...[...] :  |
 | UnsafeDeserialization.rb:80:11:80:22 | ...[...] :  | UnsafeDeserialization.rb:81:34:81:36 | xml |
+| UnsafeDeserialization.rb:86:17:86:22 | call to params :  | UnsafeDeserialization.rb:86:17:86:28 | ...[...] :  |
+| UnsafeDeserialization.rb:86:17:86:28 | ...[...] :  | UnsafeDeserialization.rb:87:29:87:37 | yaml_path |
+| UnsafeDeserialization.rb:92:17:92:22 | call to params :  | UnsafeDeserialization.rb:92:17:92:28 | ...[...] :  |
+| UnsafeDeserialization.rb:92:17:92:28 | ...[...] :  | UnsafeDeserialization.rb:93:25:93:33 | yaml_data |
+| UnsafeDeserialization.rb:98:17:98:22 | call to params :  | UnsafeDeserialization.rb:98:17:98:28 | ...[...] :  |
+| UnsafeDeserialization.rb:98:17:98:28 | ...[...] :  | UnsafeDeserialization.rb:99:30:99:38 | yaml_path |
 nodes
 | UnsafeDeserialization.rb:9:39:9:44 | call to params :  | semmle.label | call to params :  |
 | UnsafeDeserialization.rb:9:39:9:50 | ...[...] :  | semmle.label | ...[...] :  |
@@ -42,6 +48,15 @@ nodes
 | UnsafeDeserialization.rb:80:11:80:16 | call to params :  | semmle.label | call to params :  |
 | UnsafeDeserialization.rb:80:11:80:22 | ...[...] :  | semmle.label | ...[...] :  |
 | UnsafeDeserialization.rb:81:34:81:36 | xml | semmle.label | xml |
+| UnsafeDeserialization.rb:86:17:86:22 | call to params :  | semmle.label | call to params :  |
+| UnsafeDeserialization.rb:86:17:86:28 | ...[...] :  | semmle.label | ...[...] :  |
+| UnsafeDeserialization.rb:87:29:87:37 | yaml_path | semmle.label | yaml_path |
+| UnsafeDeserialization.rb:92:17:92:22 | call to params :  | semmle.label | call to params :  |
+| UnsafeDeserialization.rb:92:17:92:28 | ...[...] :  | semmle.label | ...[...] :  |
+| UnsafeDeserialization.rb:93:25:93:33 | yaml_data | semmle.label | yaml_data |
+| UnsafeDeserialization.rb:98:17:98:22 | call to params :  | semmle.label | call to params :  |
+| UnsafeDeserialization.rb:98:17:98:28 | ...[...] :  | semmle.label | ...[...] :  |
+| UnsafeDeserialization.rb:99:30:99:38 | yaml_path | semmle.label | yaml_path |
 subpaths
 #select
 | UnsafeDeserialization.rb:10:27:10:41 | serialized_data | UnsafeDeserialization.rb:9:39:9:44 | call to params :  | UnsafeDeserialization.rb:10:27:10:41 | serialized_data | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:9:39:9:44 | call to params | user-provided value |
@@ -53,3 +68,6 @@ subpaths
 | UnsafeDeserialization.rb:53:22:53:30 | json_data | UnsafeDeserialization.rb:51:17:51:22 | call to params :  | UnsafeDeserialization.rb:53:22:53:30 | json_data | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:51:17:51:22 | call to params | user-provided value |
 | UnsafeDeserialization.rb:68:23:68:31 | json_data | UnsafeDeserialization.rb:58:17:58:22 | call to params :  | UnsafeDeserialization.rb:68:23:68:31 | json_data | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:58:17:58:22 | call to params | user-provided value |
 | UnsafeDeserialization.rb:81:34:81:36 | xml | UnsafeDeserialization.rb:80:11:80:16 | call to params :  | UnsafeDeserialization.rb:81:34:81:36 | xml | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:80:11:80:16 | call to params | user-provided value |
+| UnsafeDeserialization.rb:87:29:87:37 | yaml_path | UnsafeDeserialization.rb:86:17:86:22 | call to params :  | UnsafeDeserialization.rb:87:29:87:37 | yaml_path | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:86:17:86:22 | call to params | user-provided value |
+| UnsafeDeserialization.rb:93:25:93:33 | yaml_data | UnsafeDeserialization.rb:92:17:92:22 | call to params :  | UnsafeDeserialization.rb:93:25:93:33 | yaml_data | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:92:17:92:22 | call to params | user-provided value |
+| UnsafeDeserialization.rb:99:30:99:38 | yaml_path | UnsafeDeserialization.rb:98:17:98:22 | call to params :  | UnsafeDeserialization.rb:99:30:99:38 | yaml_path | Unsafe deserialization depends on a $@. | UnsafeDeserialization.rb:98:17:98:22 | call to params | user-provided value |

ruby/ql/test/query-tests/security/cwe-502/unsafe-deserialization/UnsafeDeserialization.rb

@@ -80,4 +80,22 @@ def route10
     xml = params[:key]
     hash = Hash.from_trusted_xml(xml)
   end
+
+  # BAD
+  def route11
+    yaml_path = params[:key]
+    object = YAML.load_file yaml_path
+  end
+
+  # BAD
+  def route12
+    yaml_data = params[:key]
+    object = Psych.load yaml_data
+  end
+
+  # BAD
+  def route13
+    yaml_path = params[:key]
+    object = Psych.load_file yaml_path
+  end
 end