feat: return error when there are extraneous fields in the config file.

When the config file is parsed, any field that is not known causes an error instead of being ignored.

cli/src/config.rs

@@ -10,16 +10,17 @@ use strum_macros::{Display, EnumString};
 
 /// Configuration structure for "yr" commands.
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct Config {
     /// Format specific configuration information.
     pub fmt: FormatConfig,
-
     /// Check specific configuration information.
     pub check: CheckConfig,
 }
 
 /// Format specific configuration information.
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct FormatConfig {
     /// Rule specific formatting information.
     pub rule: RuleFormatConfig,
@@ -32,6 +33,7 @@ pub struct FormatConfig {
 /// Types allowed in the check.metadata table of the config file. Used to
 /// require specific metadata identifiers have specific types by "yr check".
 #[derive(Display, Deserialize, Serialize, Debug, Clone, EnumString)]
+#[serde(deny_unknown_fields)]
 pub enum MetaValueType {
     /// Represents a String type
     #[serde(rename = "string")]
@@ -69,6 +71,7 @@ pub enum MetaValueType {
 
 /// Format specific configuration information.
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct CheckConfig {
     /// Meta specific formatting information.
     // Note: Using a BTreeMap here because we want a consistent ordering when
@@ -80,6 +83,7 @@ pub struct CheckConfig {
 }
 
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct MetadataConfig {
     #[serde(rename = "type")]
     pub ty: MetaValueType,
@@ -89,6 +93,7 @@ pub struct MetadataConfig {
 
 /// Rule specific formatting information.
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct RuleFormatConfig {
     /// Indent section headers (meta, strings, condition).
     pub indent_section_headers: bool,
@@ -106,13 +111,15 @@ pub struct RuleFormatConfig {
 
 /// Meta specific formatting information.
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct MetaFormatConfig {
     /// Align values to longest key.
     pub align_values: bool,
 }
 
 /// Pattern specific formatting information.
 #[derive(Deserialize, Serialize, Debug)]
+#[serde(deny_unknown_fields)]
 pub struct PatternsFormatConfig {
     /// Align patterns to the longest name.
     pub align_values: bool,

cli/src/tests/mod.rs

@@ -448,6 +448,35 @@ warning[text_as_hex]: hex pattern could be written as text literal
         ));
 }
 
+#[test]
+fn cli_check_config_error() {
+    let temp_dir = TempDir::new().unwrap();
+    let config_file = temp_dir.child("config.toml");
+
+    config_file
+        .write_str(
+            r#"
+    [check.foo]
+    author = { type = "string"  }
+    "#,
+        )
+        .unwrap();
+
+    Command::cargo_bin("yr")
+        .unwrap()
+        .arg("--config")
+        .arg(config_file.path())
+        .arg("check")
+        .arg("src/tests/testdata/foo.yar")
+        .assert()
+        .failure()
+        .stderr(
+            predicate::str::contains(
+                r#"error: unknown field: found `foo`, expected ``metadata` or `rule_name_regexp`` for key "default.check.foo""#,
+            )
+        );
+}
+
 #[test]
 fn cli_fmt() {
     let temp_dir = TempDir::new().unwrap();