ssh-key: DSA keygen support

ssh-key/src/private.rs

@@ -452,6 +452,8 @@ impl PrivateKey {
     pub fn random(mut rng: impl CryptoRng + RngCore, algorithm: Algorithm) -> Result<Self> {
         let checkint = rng.next_u32();
         let key_data = match algorithm {
+            #[cfg(feature = "dsa")]
+            Algorithm::Dsa => KeypairData::from(DsaKeypair::random(rng)?),
             #[cfg(any(feature = "p256", feature = "p384"))]
             Algorithm::Ecdsa { curve } => KeypairData::from(EcdsaKeypair::random(rng, curve)?),
             #[cfg(feature = "ed25519")]

ssh-key/src/private/dsa.rs

@@ -13,6 +13,9 @@ use crate::Error;
 #[cfg(feature = "subtle")]
 use subtle::{Choice, ConstantTimeEq};
 
+#[cfg(all(feature = "dsa", feature = "rand_core"))]
+use rand_core::{CryptoRng, RngCore};
+
 /// Digital Signature Algorithm (DSA) private key.
 ///
 /// Uniformly random integer `x`, such that `0 < x < q`, i.e. `x` is in the
@@ -147,6 +150,21 @@ pub struct DsaKeypair {
     pub private: DsaPrivateKey,
 }
 
+impl DsaKeypair {
+    /// Key size.
+    #[cfg(all(feature = "dsa", feature = "rand_core"))]
+    #[allow(deprecated)]
+    pub(crate) const KEY_SIZE: dsa::KeySize = dsa::KeySize::DSA_1024_160;
+
+    /// Generate a random DSA private key.
+    #[cfg(all(feature = "dsa", feature = "rand_core"))]
+    #[cfg_attr(docsrs, doc(cfg(all(feature = "dsa", feature = "rand_core"))))]
+    pub fn random(mut rng: impl CryptoRng + RngCore) -> Result<Self> {
+        let components = dsa::Components::generate(&mut rng, Self::KEY_SIZE);
+        dsa::SigningKey::generate(&mut rng, components).try_into()
+    }
+}
+
 impl Decode for DsaKeypair {
     fn decode(reader: &mut impl Reader) -> Result<Self> {
         let public = DsaPublicKey::decode(reader)?;