Fix read/write DER length

kellerkindt · Jan 20, 2024 · 485ccab · 485ccab
1 parent df953d4
commit 485ccab
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Showing 2 changed files with 35 additions and 7 deletions.
diff --git a/src/protocol/basic/distinguished/mod.rs b/src/protocol/basic/distinguished/mod.rs
@@ -27,8 +27,9 @@ const CLASS_BITS_APPLICATION: u8 = 0b_01_000000;
 const CLASS_BITS_CONTEXT_SPECIFIC: u8 = 0b_10_000000;
 const CLASS_BITS_PRIVATE: u8 = 0b_11_000000;
 
-const LENGTH_MASK: u8 = 0b_11_000000;
-const LENGTH_SHORT_FORM: u8 = 0b_01_000000;
+const LENGTH_SHORT_MAX_VALUE: usize = 127;
+const LENGTH_BIT_MASK: u8 = 0b1_0000000;
+const LENGTH_BIT_SHORT_FORM: u8 = 0b0_0000000;
 
 impl<T: Read> BasicRead for T {
     type Flavor = DistinguishedEncodingRules;
@@ -53,8 +54,8 @@ impl<T: Read> BasicRead for T {
     fn read_length(&mut self) -> Result<usize, Error> {
         let mut bytes = [0u8; 1];
         self.read_exact(&mut bytes[..])?;
-        if bytes[0] & LENGTH_MASK == LENGTH_SHORT_FORM {
-            Ok(usize::from(bytes[0] & !LENGTH_MASK))
+        if bytes[0] & LENGTH_BIT_MASK == LENGTH_BIT_SHORT_FORM {
+            Ok(usize::from(bytes[0] & !LENGTH_BIT_MASK))
         } else {
             todo!()
         }
@@ -86,9 +87,9 @@ impl<T: Write> BasicWrite for T {
 
     #[inline]
     fn write_length(&mut self, length: usize) -> Result<(), Error> {
-        let byte = if length < 64 {
+        let byte = if length <= LENGTH_SHORT_MAX_VALUE {
             // short form 8.1.3.4
-            LENGTH_SHORT_FORM | (length as u8)
+            LENGTH_BIT_SHORT_FORM | (length as u8)
         } else {
             // long  form 8.1.3.5
             todo!()

diff --git a/tests/der_basic_boolean.rs b/tests/der_basic_boolean.rs
@@ -11,7 +11,7 @@ pub fn test_der_basic_boolean() {
         Boolean::<NoConstraint>::write_value(&mut writer, &bool_value).unwrap();
 
         assert_eq!(
-            &[0x01, 0x41, if bool_value { 0x01 } else { 0x00 }],
+            &[0x01, 0x01, if bool_value { 0x01 } else { 0x00 }],
             &buffer[..]
         );
 
@@ -21,3 +21,30 @@ pub fn test_der_basic_boolean() {
         assert_eq!(bool_value, result)
     }
 }
+
+#[test]
+pub fn test_der_basic_boolean_false_from_0x00() {
+    let mut reader = DER::reader(&[0x01, 0x01, 0xFF][..]);
+    let result = Boolean::<NoConstraint>::read_value(&mut reader).unwrap();
+
+    assert_eq!(true, result)
+}
+
+#[test]
+pub fn test_der_basic_boolean_true_from_0xff() {
+    let mut reader = DER::reader(&[0x01, 0x01, 0xFF][..]);
+    let result = Boolean::<NoConstraint>::read_value(&mut reader).unwrap();
+
+    assert_eq!(true, result)
+}
+
+#[test]
+pub fn test_der_basic_boolean_true_from_any_greater_zero() {
+    for value in 1..=u8::MAX {
+        let values = [0x01, 0x01, value];
+        let mut reader = DER::reader(&values[..]);
+        let result = Boolean::<NoConstraint>::read_value(&mut reader).unwrap();
+
+        assert_eq!(true, result)
+    }
+}