ssh-key: add SshSig serializing/deserializing using serde

ssh-key/src/sshsig.rs

@@ -14,6 +14,9 @@ use crate::{PrivateKey, PublicKey};
 
 type Version = u32;
 
+#[cfg(feature = "serde")]
+use serde::{de, ser, Deserialize, Serialize};
+
 /// `sshsig` provides a general-purpose signature format based on SSH keys and
 /// wire formats.
 ///
@@ -202,6 +205,7 @@ impl SshSig {
     }
 
     /// Get the hash algorithm used to produce this signature.
+
     ///
     /// Data to be signed is first hashed with the specified `hash_alg`.
     /// This is done to limit the amount of data presented to the signature
@@ -346,3 +350,38 @@ impl Encode for SignedData<'_> {
         Ok(())
     }
 }
+
+#[cfg(feature = "serde")]
+impl<'de> Deserialize<'de> for SshSig {
+    fn deserialize<D>(deserializer: D) -> core::result::Result<Self, D::Error>
+    where
+        D: de::Deserializer<'de>,
+    {
+        if deserializer.is_human_readable() {
+            let string = String::deserialize(deserializer)?;
+            string.parse::<SshSig>().map_err(de::Error::custom)
+        } else {
+            let bytes = Vec::<u8>::deserialize(deserializer)?;
+            let mut bytes_slice: &[u8] = &bytes;
+            Self::decode(&mut bytes_slice).map_err(de::Error::custom)
+        }
+    }
+}
+
+#[cfg(feature = "serde")]
+impl Serialize for SshSig {
+    fn serialize<S>(&self, serializer: S) -> core::result::Result<S::Ok, S::Error>
+    where
+        S: ser::Serializer,
+    {
+        if serializer.is_human_readable() {
+            self.to_pem(LineEnding::LF)
+                .map_err(ser::Error::custom)?
+                .serialize(serializer)
+        } else {
+            let mut bytes = Vec::new();
+            self.encode(&mut bytes).map_err(ser::Error::custom)?;
+            bytes.serialize(serializer)
+        }
+    }
+}