Only accept PKCS#8 keys

Author: kazk

src/imp/openssl.rs

@@ -117,6 +117,7 @@ pub enum Error {
     Normal(ErrorStack),
     Ssl(ssl::Error, X509VerifyResult),
     EmptyChain,
+    NotPkcs8,
 }
 
 impl error::Error for Error {
@@ -125,6 +126,7 @@ impl error::Error for Error {
             Error::Normal(ref e) => error::Error::source(e),
             Error::Ssl(ref e, _) => error::Error::source(e),
             Error::EmptyChain => None,
+            Error::NotPkcs8 => None,
         }
     }
 }
@@ -139,6 +141,7 @@ impl fmt::Display for Error {
                 fmt,
                 "at least one certificate must be provided to create an identity"
             ),
+            Error::NotPkcs8 => write!(fmt, "expected PKCS#8 PEM"),
         }
     }
 }
@@ -171,6 +174,10 @@ impl Identity {
     }
 
     pub fn from_pkcs8(buf: &[u8], key: &[u8]) -> Result<Identity, Error> {
+        if !key.starts_with(b"-----BEGIN PRIVATE KEY-----") {
+            return Err(Error::NotPkcs8);
+        }
+
         let pkey = PKey::private_key_from_pem(key)?;
         let mut cert_chain = X509::stack_from_pem(buf)?.into_iter();
         let cert = cert_chain.next().ok_or(Error::EmptyChain)?;

src/imp/schannel.rs

@@ -96,6 +96,10 @@ impl Identity {
     }
 
     pub fn from_pkcs8(pem: &[u8], key: &[u8]) -> Result<Identity, Error> {
+        if !key.starts_with(b"-----BEGIN PRIVATE KEY-----") {
+            return Err(io::Error::new(io::ErrorKind::InvalidInput, "not a PKCS#8 key").into());
+        }
+
         let mut store = Memory::new()?.into_store();
         let mut cert_iter = pem::PemBlock::new(pem).into_iter();
         let leaf = cert_iter.next().ok_or_else(|| {

src/imp/security_framework.rs

@@ -85,6 +85,10 @@ pub struct Identity {
 
 impl Identity {
     pub fn from_pkcs8(pem: &[u8], key: &[u8]) -> Result<Identity, Error> {
+        if !key.starts_with(b"-----BEGIN PRIVATE KEY-----") {
+            return Err(Error(base::Error::from(errSecParam)));
+        }
+
         let dir = TempDir::new().map_err(|_| Error(base::Error::from(errSecIO)))?;
         let keychain = keychain::CreateOptions::new()
             .password("password")

src/test.rs

@@ -356,6 +356,16 @@ fn import_same_identity_multiple_times() {
     let _ = p!(Identity::from_pkcs8(&cert, &key));
 }
 
+#[test]
+fn from_pkcs8_rejects_rsa_key() {
+    let keys = test_cert_gen::keys();
+    let cert = keys.server.cert_and_key.cert.to_pem().into_bytes();
+    let rsa_key = key_to_pem(keys.server.cert_and_key.key.get_der());
+    assert!(Identity::from_pkcs8(&cert, rsa_key.as_bytes()).is_err());
+    let pkcs8_key = rsa_to_pkcs8(&rsa_key);
+    assert!(Identity::from_pkcs8(&cert, pkcs8_key.as_bytes()).is_ok());
+}
+
 #[test]
 fn shutdown() {
     let keys = test_cert_gen::keys();