Merge pull request #347 from fortanix/mz/rsa-key-from-components

Add Pk::private_from_rsa_components and Pk::public_from_rsa_components

Author: mzohreva

mbedtls/src/pk/mod.rs

@@ -138,6 +138,34 @@ const CUSTOM_PK_INFO: pk_info_t = {
     }
 };
 
+/// RSA components for constructing a private key.
+pub enum RsaPrivateComponents<'a> {
+    WithPrimes {
+        /// Private 1st prime
+        p: &'a Mpi,
+        /// Private 2nd prime
+        q: &'a Mpi,
+        /// Public exponent
+        e: &'a Mpi,
+    },
+    WithPrivateExponent {
+        /// Public modulus
+        n: &'a Mpi,
+        /// Private exponent
+        d: &'a Mpi,
+        /// Public exponent
+        e: &'a Mpi,
+    },
+}
+
+/// RSA components for constructing a public key.
+pub struct RsaPublicComponents<'a> {
+    /// Public modulus
+    pub n: &'a Mpi,
+    /// Public exponent
+    pub e: &'a Mpi,
+}
+
 // If this changes then certificate.rs unsafe code in public_key needs to also
 // change.
 define!(
@@ -200,7 +228,7 @@ define!(
 // - Only const access to context: eckey_check_pair, eckey_get_bitlen,
 //   eckey_can_do, eckey_check_pair
 //
-// - Const acccess / copies context to a stack based variable eckey_verify_wrap,
+// - Const access / copies context to a stack based variable eckey_verify_wrap,
 //   eckey_sign_wrap: ../../../mbedtls-sys/vendor/crypto/library/pk_wrap.c:251
 //   creates a stack ecdsa variable and uses ctx to initialize it. ctx is passed
 //   as 'key', a const pointer to mbedtls_ecdsa_from_keypair( &ecdsa, ctx )
@@ -348,7 +376,7 @@ Please use `private_from_ec_components_with_rng` instead."
     ///
     /// This function will return an error if:
     ///
-    /// * Fails to genearte `EcPoint` from given EcGroup in `curve`.
+    /// * Fails to generate `EcPoint` from given EcGroup in `curve`.
     /// * The underlying C `mbedtls_pk_setup` function fails to set up the `Pk` context.
     /// * The `EcPoint::mul` function fails to generate the public key point.
     pub fn private_from_ec_components_with_rng<F: Random>(mut curve: EcGroup, private_key: Mpi, rng: &mut F) -> Result<Pk> {
@@ -376,6 +404,39 @@ Please use `private_from_ec_components_with_rng` instead."
         Ok(ret)
     }
 
+    /// Construct a private key from RSA components.
+    pub fn private_from_rsa_components(components: RsaPrivateComponents<'_>) -> Result<Pk> {
+        let mut ret = Self::init();
+        let (n, p, q, d, e) = match components {
+            RsaPrivateComponents::WithPrimes { p, q, e } => (None, Some(p), Some(q), None, Some(e)),
+            RsaPrivateComponents::WithPrivateExponent { n, d, e } => (Some(n), None, None, Some(d), Some(e)),
+        };
+        let to_ptr = |mpi: Option<&Mpi>| match mpi {
+            None => ptr::null(),
+            Some(mpi) => mpi.handle(),
+        };
+        unsafe {
+            pk_setup(&mut ret.inner, pk_info_from_type(Type::Rsa.into())).into_result()?;
+            let ctx = ret.inner.pk_ctx as *mut rsa_context;
+            rsa_import(ctx, to_ptr(n), to_ptr(p), to_ptr(q), to_ptr(d), to_ptr(e)).into_result()?;
+            rsa_complete(ctx).into_result()?;
+        }
+        Ok(ret)
+    }
+
+    /// Construct a public key from RSA components.
+    pub fn public_from_rsa_components(components: RsaPublicComponents<'_>) -> Result<Pk> {
+        let mut ret = Self::init();
+        let RsaPublicComponents { n, e } = components;
+        unsafe {
+            pk_setup(&mut ret.inner, pk_info_from_type(Type::Rsa.into())).into_result()?;
+            let ctx = ret.inner.pk_ctx as *mut rsa_context;
+            rsa_import(ctx, n.handle(), ptr::null(), ptr::null(), ptr::null(), e.handle()).into_result()?;
+            rsa_complete(ctx).into_result()?;
+        }
+        Ok(ret)
+    }
+
     pub fn public_custom_algo(algo_id: &[u64], pk: &[u8]) -> Result<Pk> {
         let mut ret = Self::init();
         unsafe {
@@ -1564,4 +1625,37 @@ iy6KC991zzvaWY/Ys+q/84Afqa+0qJKQnPuy/7F5GkVdQA/lfbhi
             assert_eq!(l.unwrap(), LEN);
         }
     }
+
+    #[test]
+    fn private_from_rsa_components_sanity() {
+        let mut pk = Pk::generate_rsa(&mut crate::test_support::rand::test_rng(), 2048, 0x10001).unwrap();
+        let components = RsaPrivateComponents::WithPrimes {
+            p: &pk.rsa_private_prime1().unwrap(),
+            q: &pk.rsa_private_prime2().unwrap(),
+            e: &Mpi::new(pk.rsa_public_exponent().unwrap() as _).unwrap(),
+        };
+        let mut pk2 = Pk::private_from_rsa_components(components).unwrap();
+        assert_eq!(pk.write_private_der_vec().unwrap(), pk2.write_private_der_vec().unwrap());
+
+        let components = RsaPrivateComponents::WithPrivateExponent {
+            n: &pk.rsa_public_modulus().unwrap(),
+            d: &pk.rsa_private_exponent().unwrap(),
+            e: &Mpi::new(pk.rsa_public_exponent().unwrap() as _).unwrap(),
+        };
+        let mut pk3 = Pk::private_from_rsa_components(components).unwrap();
+        assert_eq!(pk.write_private_der_vec().unwrap(), pk3.write_private_der_vec().unwrap());
+    }
+
+    #[test]
+    fn public_from_rsa_components_sanity() {
+        let mut pk = Pk::generate_rsa(&mut crate::test_support::rand::test_rng(), 2048, 0x10001).unwrap();
+        let mut pk = Pk::from_public_key(&pk.write_public_der_vec().unwrap()).unwrap();
+
+        let components = RsaPublicComponents {
+            n: &pk.rsa_public_modulus().unwrap(),
+            e: &Mpi::new(pk.rsa_public_exponent().unwrap() as _).unwrap(),
+        };
+        let mut pk2 = Pk::public_from_rsa_components(components).unwrap();
+        assert_eq!(pk.write_public_der_vec().unwrap(), pk2.write_public_der_vec().unwrap());
+    }
 }