hex encode signature and file hash values

According to theupdateframework/specification#42, the signature and file hash values should be hex encoded. Change-Id: I14710a062fae3adfc4bc6b86fbbf533ce1b97070
erickt · Aug 1, 2019 · 0069f17 · 0069f17
1 parent bfdbeb2
commit 0069f17
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Showing 5 changed files with 45 additions and 59 deletions.
diff --git a/src/crypto.rs b/src/crypto.rs
@@ -1,6 +1,6 @@
 //! Cryptographic structures and functions.
 
-use data_encoding::BASE64URL;
+use data_encoding::{BASE64URL, HEXLOWER};
 use derp::{self, Der, Tag};
 use ring;
 use ring::digest::{self, SHA256, SHA512};
@@ -207,8 +207,8 @@ pub enum SignatureScheme {
 }
 
 /// Wrapper type for the value of a cryptographic signature.
-#[derive(Clone, PartialEq)]
-pub struct SignatureValue(Vec<u8>);
+#[derive(Clone, PartialEq, Serialize, Deserialize)]
+pub struct SignatureValue(#[serde(with = "crate::format_hex")] Vec<u8>);
 
 impl SignatureValue {
     /// Create a new `SignatureValue` from the given bytes.
@@ -218,35 +218,17 @@ impl SignatureValue {
         SignatureValue(bytes)
     }
 
-    /// Create a new `SignatureValue` from the given base64url string.
+    /// Create a new `SignatureValue` from the given hex string.
     ///
     /// Note: It is unlikely that you ever want to do this manually.
-    pub fn from_string(string: &str) -> Result<Self> {
-        Ok(SignatureValue(BASE64URL.decode(string.as_bytes())?))
+    pub fn from_hex(string: &str) -> Result<Self> {
+        Ok(SignatureValue(HEXLOWER.decode(string.as_bytes())?))
     }
 }
 
 impl Debug for SignatureValue {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "SignatureValue {{ \"{}\" }}", BASE64URL.encode(&self.0))
-    }
-}
-
-impl Serialize for SignatureValue {
-    fn serialize<S>(&self, ser: S) -> ::std::result::Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        BASE64URL.encode(&self.0).serialize(ser)
-    }
-}
-
-impl<'de> Deserialize<'de> for SignatureValue {
-    fn deserialize<D: Deserializer<'de>>(de: D) -> ::std::result::Result<Self, D::Error> {
-        let string: String = Deserialize::deserialize(de)?;
-        SignatureValue::from_string(&string).map_err(|e| {
-            DeserializeError::custom(format!("Signature value was not valid base64url: {:?}", e))
-        })
+        write!(f, "SignatureValue {{ \"{}\" }}", HEXLOWER.encode(&self.0))
     }
 }
 
@@ -712,8 +694,8 @@ pub enum HashAlgorithm {
 }
 
 /// Wrapper for the value of a hash digest.
-#[derive(Clone, Eq, PartialEq, Hash)]
-pub struct HashValue(Vec<u8>);
+#[derive(Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
+pub struct HashValue(#[serde(with = "crate::format_hex")] Vec<u8>);
 
 impl HashValue {
     /// Create a new `HashValue` from the given digest bytes.
@@ -727,34 +709,15 @@ impl HashValue {
     }
 }
 
-impl Serialize for HashValue {
-    fn serialize<S>(&self, ser: S) -> ::std::result::Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        BASE64URL.encode(&self.0).serialize(ser)
-    }
-}
-
-impl<'de> Deserialize<'de> for HashValue {
-    fn deserialize<D: Deserializer<'de>>(de: D) -> ::std::result::Result<Self, D::Error> {
-        let s: String = Deserialize::deserialize(de)?;
-        let bytes = BASE64URL
-            .decode(s.as_bytes())
-            .map_err(|e| DeserializeError::custom(format!("Base64: {:?}", e)))?;
-        Ok(HashValue(bytes))
-    }
-}
-
 impl Debug for HashValue {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "HashValue {{ \"{}\" }}", BASE64URL.encode(&self.0))
+        write!(f, "HashValue {{ \"{}\" }}", HEXLOWER.encode(&self.0))
     }
 }
 
 impl Display for HashValue {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", BASE64URL.encode(&self.0))
+        write!(f, "{}", HEXLOWER.encode(&self.0))
     }
 }
 
@@ -913,10 +876,10 @@ mod test {
 
     #[test]
     fn serde_signature_value() {
-        let s = "T5vfRrM1iHpgzGwAHe7MbJH_7r4chkOAphV3OPCCv0I=";
+        let s = "4750eaf6878740780d6f97b12dbad079fb012bec88c78de2c380add56d3f51db";
         let jsn = json!(s);
         let parsed: SignatureValue = serde_json::from_str(&format!("\"{}\"", s)).unwrap();
-        assert_eq!(parsed, SignatureValue::from_string(s).unwrap());
+        assert_eq!(parsed, SignatureValue::from_hex(s).unwrap());
         let encoded = serde_json::to_value(&parsed).unwrap();
         assert_eq!(encoded, jsn);
     }
@@ -959,8 +922,9 @@ mod test {
         let encoded = serde_json::to_value(&sig).unwrap();
         let jsn = json!({
             "keyid": "qfrfBrkB4lBBSDEBlZgaTGS_SrE6UfmON9kP4i3dJFY=",
-            "value": "_k0Tsqc8Azod5_UQeyBfx7oOFWbLlbkjScrmqkU4lWATv-D3v5d8sHK7Z\
-                eh4K18zoFc_54gWKZoBfKW6VZ45DA==",
+            "value": "fe4d13b2a73c033a1de7f5107b205fc7ba0e1566cb95b92349cae6aa4\
+                538956013bfe0f7bf977cb072bb65e8782b5f33a0573fe78816299a017ca5ba\
+                559e390c",
             }
         );
         assert_eq!(encoded, jsn);

diff --git a/src/format_hex.rs b/src/format_hex.rs
@@ -0,0 +1,18 @@
+use data_encoding::HEXLOWER;
+use serde::{self, Deserialize, Deserializer, Serializer};
+use std::result::Result;
+
+pub fn serialize<S>(value: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    serializer.serialize_str(&HEXLOWER.encode(value))
+}
+
+pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let s = String::deserialize(deserializer)?;
+    HEXLOWER.decode(s.as_bytes()).map_err(serde::de::Error::custom)
+}
diff --git a/src/interchange/mod.rs b/src/interchange/mod.rs
@@ -84,9 +84,9 @@ pub trait DataInterchange: Debug + PartialEq + Clone {
 ///
 /// `SCHEME` is a string (either `ed25519`, `rsassa-pss-sha256`, or `rsassa-pss-sha512`
 ///
-/// `HASH_VALUE` is a base64url encoded hash value.
+/// `HASH_VALUE` is a hex encoded hash value.
 ///
-/// `SIG_VALUE` is a base64url encoded signature value.
+/// `SIG_VALUE` is a hex encoded signature value.
 ///
 /// `METADATA_DESCRIPTION` is the following:
 ///

diff --git a/src/lib.rs b/src/lib.rs
@@ -119,6 +119,7 @@ pub mod metadata;
 pub mod repository;
 pub mod tuf;
 
+mod format_hex;
 mod shims;
 mod util;
 

diff --git a/src/metadata.rs b/src/metadata.rs
@@ -857,7 +857,7 @@ impl MetadataPath {
     ///            ["foo".to_string(), "1.bar.json".to_string()]);
     /// assert_eq!(path.components::<Json>(
     ///                 &MetadataVersion::Hash(HashValue::new(vec![0x69, 0xb7, 0x1d]))),
-    ///            ["foo".to_string(), "abcd.bar.json".to_string()]);
+    ///            ["foo".to_string(), "69b71d.bar.json".to_string()]);
     /// ```
     pub fn components<D>(&self, version: &MetadataVersion) -> Vec<String>
     where
@@ -1835,7 +1835,8 @@ mod test {
         let jsn = json!({
             "length": 30,
             "hashes": {
-                "sha256": "_F10XHEryG6poxJk2sDJVu61OFf2d-7QWCm7cQE8rhg=",
+                "sha256": "fc5d745c712bc86ea9a31264dac0c956eeb53857f677eed05829\
+                    bb71013cae18",
             },
         });
         let parsed_str: TargetDescription = serde_json::from_str(&jsn_str).unwrap();
@@ -2046,7 +2047,8 @@ mod test {
                 "foo": {
                     "length": 3,
                     "hashes": {
-                        "sha256": "LCa0a2j_xo_5m0U8HTBBNBNCLXBkg7-g-YpeiGJm564=",
+                        "sha256": "2c26b46b68ffc68ff99b453c1d30413413422d706483\
+                            bfa0f98a5e886266e7ae",
                     },
                 },
             },
@@ -2136,8 +2138,9 @@ mod test {
             "signatures": [
                 {
                     "keyid": "qfrfBrkB4lBBSDEBlZgaTGS_SrE6UfmON9kP4i3dJFY=",
-                    "value": "5zv0RA1_apWwMHNRgcuhkNwnz1iNj8aPkZrA3bruehf5ncKiPekLHGVJWWodPEIESj\
-                        9k9FBLI4TK422Y7RR2AQ==",
+                    "value": "e73bf4440d7f6a95b030735181cba190dc27cf588d8fc68f9\
+                        19ac0ddbaee7a17f99dc2a23de90b1c6549596a1d3c42044a3f64f4\
+                        504b2384cae36d98ed147601",
                 }
             ],
             "signed": {