ECDSA support through OpenSSL 3.* API

Signed-off-by: Jakub Jelen <[email protected]>

Author: Jakuje

openssl/src/lib.rs

@@ -186,6 +186,8 @@ pub mod pkcs7;
 pub mod pkey;
 pub mod pkey_ctx;
 #[cfg(ossl300)]
+pub mod pkey_ecdsa;
+#[cfg(ossl300)]
 pub mod pkey_rsa;
 #[cfg(ossl300)]
 pub mod provider;

openssl/src/pkey_ecdsa.rs

@@ -0,0 +1,209 @@
+//! Elliptic Curve using OpenSSL 3.* API
+//!
+//! Cryptography relies on the difficulty of solving mathematical problems, such as the factor
+//! of large integers composed of two large prime numbers and the discrete logarithm of a
+//! random elliptic curve.  This module provides low-level features of the latter.
+//! Elliptic Curve protocols can provide the same security with smaller keys.
+
+use foreign_types::ForeignType;
+use libc::c_int;
+use std::ptr;
+
+use crate::bn::{BigNum, BigNumRef};
+use crate::error::ErrorStack;
+use crate::ossl_param::{OsslParam, OsslParamBuilder};
+use crate::pkey::{PKey, Private, Public};
+use crate::pkey_ctx::PkeyCtx;
+use crate::{cvt, cvt_p};
+use openssl_macros::corresponds;
+
+const OSSL_PKEY_PARAM_GROUP_NAME: &[u8; 6] = b"group\0";
+const OSSL_PKEY_PARAM_PUB_KEY: &[u8; 4] = b"pub\0";
+const OSSL_PKEY_PARAM_PRIV_KEY: &[u8; 5] = b"priv\0";
+
+pub struct PKeyEcdsaBuilder<T> {
+    bld: OsslParamBuilder,
+    _m: ::std::marker::PhantomData<T>,
+}
+
+impl<T> PKeyEcdsaBuilder<T> {
+    /// Creates a new `PKeyEcdsaBuilder` to build ECDSA private or public keys.
+    ///
+    /// `n` is the modulus common to both public and private key.
+    /// `e` is the public exponent and `d` is the private exponent.
+    ///
+    pub fn new(
+        group: &str,
+        point: &[u8],
+        private: Option<&BigNumRef>,
+    ) -> Result<PKeyEcdsaBuilder<T>, ErrorStack> {
+        let bld = OsslParamBuilder::new()?;
+        bld.add_utf8_string(OSSL_PKEY_PARAM_GROUP_NAME, group)?;
+        bld.add_octet_string(OSSL_PKEY_PARAM_PUB_KEY, point)?;
+        if let Some(private) = private {
+            bld.add_bn(OSSL_PKEY_PARAM_PRIV_KEY, private)?
+        };
+        Ok(PKeyEcdsaBuilder::<T> {
+            bld,
+            _m: ::std::marker::PhantomData,
+        })
+    }
+
+    /// Build PKey. Internal.
+    #[corresponds(EVP_PKEY_fromdata)]
+    fn build_internal(self, selection: c_int) -> Result<PKey<T>, ErrorStack> {
+        let mut ctx = PkeyCtx::new_from_name(None, "EC", None)?;
+        ctx.fromdata_init()?;
+        let params = self.bld.to_param()?;
+        unsafe {
+            let evp = cvt_p(ffi::EVP_PKEY_new())?;
+            let pkey = PKey::from_ptr(evp);
+            cvt(ffi::EVP_PKEY_fromdata(
+                ctx.as_ptr(),
+                &mut pkey.as_ptr(),
+                selection,
+                params.as_ptr(),
+            ))?;
+            Ok(pkey)
+        }
+    }
+}
+
+impl PKeyEcdsaBuilder<Private> {
+    /// Returns the Private ECDSA PKey from the provided parameters.
+    #[corresponds(EVP_PKEY_fromdata)]
+    pub fn build(self) -> Result<PKey<Private>, ErrorStack> {
+        /* The ECDSA requires here a keypair as the private key does not work without public point! */
+        self.build_internal(ffi::EVP_PKEY_KEYPAIR)
+    }
+}
+
+impl PKeyEcdsaBuilder<Public> {
+    /// Returns the Public ECDSA PKey from the provided parameters.
+    #[corresponds(EVP_PKEY_fromdata)]
+    pub fn build(self) -> Result<PKey<Public>, ErrorStack> {
+        self.build_internal(ffi::EVP_PKEY_PUBLIC_KEY)
+    }
+}
+
+pub struct PKeyEcdsaParams<T> {
+    params: OsslParam,
+    _m: ::std::marker::PhantomData<T>,
+}
+
+impl<T> PKeyEcdsaParams<T> {
+    /// Creates a new `PKeyEcdsaParams` from existing ECDSA PKey. Internal.
+    #[corresponds(EVP_PKEY_todata)]
+    fn _new_from_pkey(pkey: &PKey<T>, selection: c_int) -> Result<PKeyEcdsaParams<T>, ErrorStack> {
+        unsafe {
+            let mut params: *mut ffi::OSSL_PARAM = ptr::null_mut();
+            cvt(ffi::EVP_PKEY_todata(pkey.as_ptr(), selection, &mut params))?;
+            Ok(PKeyEcdsaParams::<T> {
+                params: OsslParam::from_ptr(params),
+                _m: ::std::marker::PhantomData,
+            })
+        }
+    }
+
+    /// Returns a reference to the public key.
+    pub fn public_key(&self) -> Result<&[u8], ErrorStack> {
+        self.params
+            .locate(OSSL_PKEY_PARAM_PUB_KEY)?
+            .get_octet_string()
+    }
+
+    /// Returns a reference to a group name
+    pub fn group(&self) -> Result<&str, ErrorStack> {
+        self.params
+            .locate(OSSL_PKEY_PARAM_GROUP_NAME)?
+            .get_utf8_string()
+    }
+}
+
+impl PKeyEcdsaParams<Public> {
+    /// Creates a new `PKeyEcdsaParams` from existing Public ECDSA PKey.
+    #[corresponds(EVP_PKEY_todata)]
+    pub fn from_pkey(pkey: &PKey<Public>) -> Result<PKeyEcdsaParams<Public>, ErrorStack> {
+        Self::_new_from_pkey(pkey, ffi::EVP_PKEY_PUBLIC_KEY)
+    }
+}
+
+impl PKeyEcdsaParams<Private> {
+    /// Creates a new `PKeyEcdsaParams` from existing Private ECDSA PKey.
+    #[corresponds(EVP_PKEY_todata)]
+    pub fn from_pkey(pkey: &PKey<Private>) -> Result<PKeyEcdsaParams<Private>, ErrorStack> {
+        Self::_new_from_pkey(pkey, ffi::EVP_PKEY_KEYPAIR)
+    }
+
+    /// Returns the private key.
+    pub fn private_key(&self) -> Result<BigNum, ErrorStack> {
+        self.params.locate(OSSL_PKEY_PARAM_PRIV_KEY)?.get_bn()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use crate::bn::BigNumContext;
+    use crate::ec::{EcKey, PointConversionForm};
+    use crate::error::Error;
+    use crate::nid::Nid;
+
+    use super::*;
+
+    #[test]
+    fn test_build_pkey_ecdsa_private() {
+        /* First, generate the key with old API */
+        let nid: Nid = Nid::SECP256K1;
+        let curve_name = nid.short_name().unwrap();
+        let group = crate::ec::EcGroup::from_curve_name(nid).unwrap();
+        let ec_key = EcKey::generate(&group).unwrap();
+        let pkey1 = PKey::from_ec_key(ec_key.clone()).unwrap();
+
+        /* Now, build the new PKey from the old key with new API */
+        let mut ctx = BigNumContext::new().unwrap();
+        let pubkey = ec_key
+            .public_key()
+            .to_bytes(&group, PointConversionForm::UNCOMPRESSED, &mut ctx)
+            .unwrap();
+        let bld = PKeyEcdsaBuilder::<Private>::new(curve_name, &pubkey, Some(ec_key.private_key()))
+            .unwrap();
+        let pkey2 = bld.build().unwrap();
+
+        /* Verify it works the same way as the old one */
+        assert!(pkey1.public_eq(&pkey2));
+        assert!(Error::get().is_none());
+
+        let params = PKeyEcdsaParams::<Private>::from_pkey(&pkey2).unwrap();
+        assert_eq!(params.group().unwrap(), curve_name);
+        assert_eq!(&params.private_key().unwrap(), ec_key.private_key());
+        assert_eq!(params.public_key().unwrap(), pubkey);
+    }
+
+    #[test]
+    fn test_build_pkey_ecdsa_public() {
+        /* First, generate the key with old API */
+        let nid: Nid = Nid::SECP256K1;
+        let curve_name = nid.short_name().unwrap();
+        let group = crate::ec::EcGroup::from_curve_name(nid).unwrap();
+        let ec_key = EcKey::generate(&group).unwrap();
+        let pkey1 = PKey::from_ec_key(ec_key.clone()).unwrap();
+
+        /* Now, build the new PKey from the old key with new API */
+        let mut ctx = BigNumContext::new().unwrap();
+        let pubkey = ec_key
+            .public_key()
+            .to_bytes(&group, PointConversionForm::UNCOMPRESSED, &mut ctx)
+            .unwrap();
+        let bld = PKeyEcdsaBuilder::<Public>::new(curve_name, &pubkey, None).unwrap();
+        let pkey2 = bld.build().unwrap();
+
+        /* Verify it works the same way as the old one */
+        assert!(pkey1.public_eq(&pkey2));
+        assert!(Error::get().is_none());
+
+        let params = PKeyEcdsaParams::<Public>::from_pkey(&pkey2).unwrap();
+        assert_eq!(params.group().unwrap(), curve_name);
+        assert_eq!(params.public_key().unwrap(), pubkey);
+    }
+}