[PM-12400] Add private key regeneration SDK methods (#6)

## 🎟️ Tracking

<!-- Paste the link to the Jira or GitHub issue or otherwise describe /
point to where this change is coming from. -->
https://bitwarden.atlassian.net/browse/PM-12400

## 📔 Objective

<!-- Describe what the purpose of this PR is, for example what bug
you're fixing or new feature you're adding. -->
Add shared methods to enable private key regeneration in clients.

crates/bitwarden-core/src/mobile/client_crypto.rs

@@ -1,7 +1,10 @@
 #[cfg(feature = "internal")]
 use bitwarden_crypto::{AsymmetricEncString, EncString};
 
-use super::crypto::{derive_key_connector, DeriveKeyConnectorRequest};
+use super::crypto::{
+    derive_key_connector, make_key_pair, verify_asymmetric_keys, DeriveKeyConnectorRequest,
+    MakeKeyPairResponse, VerifyAsymmetricKeysRequest, VerifyAsymmetricKeysResponse,
+};
 use crate::{client::encryption_settings::EncryptionSettingsError, Client};
 #[cfg(feature = "internal")]
 use crate::{
@@ -56,6 +59,17 @@ impl<'a> ClientCrypto<'a> {
     pub fn derive_key_connector(&self, request: DeriveKeyConnectorRequest) -> Result<String> {
         derive_key_connector(request)
     }
+
+    pub fn make_key_pair(&self, user_key: String) -> Result<MakeKeyPairResponse> {
+        make_key_pair(user_key)
+    }
+
+    pub fn verify_asymmetric_keys(
+        &self,
+        request: VerifyAsymmetricKeysRequest,
+    ) -> Result<VerifyAsymmetricKeysResponse> {
+        verify_asymmetric_keys(request)
+    }
 }
 
 impl<'a> Client {

crates/bitwarden-core/src/mobile/crypto.rs

@@ -1,8 +1,9 @@
 use std::collections::HashMap;
 
+use base64::{engine::general_purpose::STANDARD, Engine};
 use bitwarden_crypto::{
-    AsymmetricEncString, EncString, Kdf, KeyDecryptable, KeyEncryptable, MasterKey,
-    SymmetricCryptoKey,
+    AsymmetricCryptoKey, AsymmetricEncString, EncString, Kdf, KeyDecryptable, KeyEncryptable,
+    MasterKey, SymmetricCryptoKey, UserKey,
 };
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
@@ -350,10 +351,115 @@ pub(super) fn derive_key_connector(request: DeriveKeyConnectorRequest) -> Result
     Ok(master_key.to_base64())
 }
 
+#[derive(Serialize, Deserialize, Debug, JsonSchema)]
+#[serde(rename_all = "camelCase", deny_unknown_fields)]
+#[cfg_attr(feature = "uniffi", derive(uniffi::Record))]
+#[cfg_attr(feature = "wasm", derive(Tsify), tsify(into_wasm_abi, from_wasm_abi))]
+pub struct MakeKeyPairResponse {
+    /// The user's public key
+    user_public_key: String,
+    /// User's private key, encrypted with the user key
+    user_key_encrypted_private_key: EncString,
+}
+
+pub fn make_key_pair(user_key: String) -> Result<MakeKeyPairResponse> {
+    let user_key = UserKey::new(SymmetricCryptoKey::try_from(user_key)?);
+
+    let key_pair = user_key.make_key_pair()?;
+
+    Ok(MakeKeyPairResponse {
+        user_public_key: key_pair.public,
+        user_key_encrypted_private_key: key_pair.private,
+    })
+}
+
+#[derive(Serialize, Deserialize, Debug, JsonSchema)]
+#[serde(rename_all = "camelCase", deny_unknown_fields)]
+#[cfg_attr(feature = "uniffi", derive(uniffi::Record))]
+#[cfg_attr(feature = "wasm", derive(Tsify), tsify(into_wasm_abi, from_wasm_abi))]
+pub struct VerifyAsymmetricKeysRequest {
+    /// The user's user key
+    user_key: String,
+    /// The user's public key
+    user_public_key: String,
+    /// User's private key, encrypted with the user key
+    user_key_encrypted_private_key: EncString,
+}
+
+#[derive(Serialize, Deserialize, Debug, JsonSchema)]
+#[serde(rename_all = "camelCase", deny_unknown_fields)]
+#[cfg_attr(feature = "uniffi", derive(uniffi::Record))]
+#[cfg_attr(feature = "wasm", derive(Tsify), tsify(into_wasm_abi, from_wasm_abi))]
+pub struct VerifyAsymmetricKeysResponse {
+    /// Whether the user's private key was decryptable by the user key.
+    private_key_decryptable: bool,
+    /// Whether the user's private key was a valid RSA key and matched the public key provided.
+    valid_private_key: bool,
+}
+
+pub fn verify_asymmetric_keys(
+    request: VerifyAsymmetricKeysRequest,
+) -> Result<VerifyAsymmetricKeysResponse> {
+    #[derive(Debug, thiserror::Error)]
+    enum VerifyError {
+        #[error("Failed to decrypt private key: {0:?}")]
+        DecryptFailed(bitwarden_crypto::CryptoError),
+        #[error("Failed to parse decrypted private key: {0:?}")]
+        ParseFailed(bitwarden_crypto::CryptoError),
+        #[error("Failed to derive a public key: {0:?}")]
+        PublicFailed(bitwarden_crypto::CryptoError),
+        #[error("Derived public key doesn't match")]
+        KeyMismatch,
+    }
+
+    fn verify_inner(
+        user_key: &SymmetricCryptoKey,
+        request: &VerifyAsymmetricKeysRequest,
+    ) -> Result<(), VerifyError> {
+        let decrypted_private_key: Vec<u8> = request
+            .user_key_encrypted_private_key
+            .decrypt_with_key(user_key)
+            .map_err(VerifyError::DecryptFailed)?;
+
+        let private_key = AsymmetricCryptoKey::from_der(&decrypted_private_key)
+            .map_err(VerifyError::ParseFailed)?;
+
+        let derived_public_key_vec = private_key
+            .to_public_der()
+            .map_err(VerifyError::PublicFailed)?;
+
+        let derived_public_key = STANDARD.encode(&derived_public_key_vec);
+
+        if derived_public_key != request.user_public_key {
+            return Err(VerifyError::KeyMismatch);
+        }
+        Ok(())
+    }
+
+    let user_key = SymmetricCryptoKey::try_from(request.user_key.clone())?;
+
+    Ok(match verify_inner(&user_key, &request) {
+        Ok(_) => VerifyAsymmetricKeysResponse {
+            private_key_decryptable: true,
+            valid_private_key: true,
+        },
+        Err(e) => {
+            log::debug!("User asymmetric keys verification: {}", e);
+
+            VerifyAsymmetricKeysResponse {
+                private_key_decryptable: !matches!(e, VerifyError::DecryptFailed(_)),
+                valid_private_key: false,
+            }
+        }
+    })
+}
+
 #[cfg(test)]
 mod tests {
     use std::num::NonZeroU32;
 
+    use bitwarden_crypto::RsaKeyPair;
+
     use super::*;
     use crate::Client;
 
@@ -585,4 +691,99 @@ mod tests {
 
         assert_eq!(result, "ySXq1RVLKEaV1eoQE/ui9aFKIvXTl9PAXwp1MljfF50=");
     }
+
+    fn setup_asymmetric_keys_test() -> (UserKey, RsaKeyPair) {
+        let master_key = MasterKey::derive(
+            "asdfasdfasdf",
+            "[email protected]",
+            &Kdf::PBKDF2 {
+                iterations: NonZeroU32::new(600_000).unwrap(),
+            },
+        )
+        .unwrap();
+        let user_key = (master_key.make_user_key().unwrap()).0;
+        let key_pair = user_key.make_key_pair().unwrap();
+
+        (user_key, key_pair)
+    }
+
+    #[test]
+    fn test_make_key_pair() {
+        let (user_key, _) = setup_asymmetric_keys_test();
+
+        let response = make_key_pair(user_key.0.to_base64()).unwrap();
+
+        assert!(!response.user_public_key.is_empty());
+        let encrypted_private_key = response.user_key_encrypted_private_key;
+        let private_key: Vec<u8> = encrypted_private_key.decrypt_with_key(&user_key.0).unwrap();
+        assert!(!private_key.is_empty());
+    }
+
+    #[test]
+    fn test_verify_asymmetric_keys_success() {
+        let (user_key, key_pair) = setup_asymmetric_keys_test();
+
+        let request = VerifyAsymmetricKeysRequest {
+            user_key: user_key.0.to_base64(),
+            user_public_key: key_pair.public,
+            user_key_encrypted_private_key: key_pair.private,
+        };
+        let response = verify_asymmetric_keys(request).unwrap();
+
+        assert!(response.private_key_decryptable);
+        assert!(response.valid_private_key);
+    }
+
+    #[test]
+    fn test_verify_asymmetric_keys_decrypt_failed() {
+        let (user_key, key_pair) = setup_asymmetric_keys_test();
+        let undecryptable_private_key = "2.cqD39M4erPZ3tWaz2Fng9w==|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|Y38qtTuCwNLDqFnzJ3Cgbjm1SE15OnhDm9iAMABaQBA=".parse().unwrap();
+
+        let request = VerifyAsymmetricKeysRequest {
+            user_key: user_key.0.to_base64(),
+            user_public_key: key_pair.public,
+            user_key_encrypted_private_key: undecryptable_private_key,
+        };
+        let response = verify_asymmetric_keys(request).unwrap();
+
+        assert!(!response.private_key_decryptable);
+        assert!(!response.valid_private_key);
+    }
+
+    #[test]
+    fn test_verify_asymmetric_keys_parse_failed() {
+        let (user_key, key_pair) = setup_asymmetric_keys_test();
+
+        let invalid_private_key = "bad_key"
+            .to_string()
+            .into_bytes()
+            .encrypt_with_key(&user_key.0)
+            .unwrap();
+
+        let request = VerifyAsymmetricKeysRequest {
+            user_key: user_key.0.to_base64(),
+            user_public_key: key_pair.public,
+            user_key_encrypted_private_key: invalid_private_key,
+        };
+        let response = verify_asymmetric_keys(request).unwrap();
+
+        assert!(response.private_key_decryptable);
+        assert!(!response.valid_private_key);
+    }
+
+    #[test]
+    fn test_verify_asymmetric_keys_key_mismatch() {
+        let (user_key, key_pair) = setup_asymmetric_keys_test();
+        let new_key_pair = user_key.make_key_pair().unwrap();
+
+        let request = VerifyAsymmetricKeysRequest {
+            user_key: user_key.0.to_base64(),
+            user_public_key: key_pair.public,
+            user_key_encrypted_private_key: new_key_pair.private,
+        };
+        let response = verify_asymmetric_keys(request).unwrap();
+
+        assert!(response.private_key_decryptable);
+        assert!(!response.valid_private_key);
+    }
 }

crates/bitwarden-wasm-internal/src/crypto.rs

@@ -2,7 +2,10 @@ use std::rc::Rc;
 
 use bitwarden_core::{
     client::encryption_settings::EncryptionSettingsError,
-    mobile::crypto::{InitOrgCryptoRequest, InitUserCryptoRequest},
+    mobile::crypto::{
+        InitOrgCryptoRequest, InitUserCryptoRequest, MakeKeyPairResponse,
+        VerifyAsymmetricKeysRequest, VerifyAsymmetricKeysResponse,
+    },
     Client,
 };
 use wasm_bindgen::prelude::*;
@@ -35,4 +38,23 @@ impl ClientCrypto {
     ) -> Result<(), EncryptionSettingsError> {
         self.0.crypto().initialize_org_crypto(req).await
     }
+
+    /// Generates a new key pair and encrypts the private key with the provided user key.
+    /// Crypto initialization not required.
+    pub fn make_key_pair(
+        &self,
+        user_key: String,
+    ) -> Result<MakeKeyPairResponse, bitwarden_core::Error> {
+        self.0.crypto().make_key_pair(user_key)
+    }
+
+    /// Verifies a user's asymmetric keys by decrypting the private key with the provided user
+    /// key. Returns if the private key is decryptable and if it is a valid matching key.
+    /// Crypto initialization not required.
+    pub fn verify_asymmetric_keys(
+        &self,
+        request: VerifyAsymmetricKeysRequest,
+    ) -> Result<VerifyAsymmetricKeysResponse, bitwarden_core::Error> {
+        self.0.crypto().verify_asymmetric_keys(request)
+    }
 }