Merge pull request #2076 from jmayclin/temp-key

add temp key bindings

Author: sfackler

openssl-sys/src/ssl.rs

@@ -349,6 +349,8 @@ pub const SSL_CTRL_SET_ECDH_AUTO: c_int = 94;
 pub const SSL_CTRL_SET_SIGALGS_LIST: c_int = 98;
 #[cfg(ossl102)]
 pub const SSL_CTRL_SET_VERIFY_CERT_STORE: c_int = 106;
+#[cfg(ossl300)]
+pub const SSL_CTRL_GET_PEER_TMP_KEY: c_int = 109;
 #[cfg(ossl110)]
 pub const SSL_CTRL_GET_EXTMS_SUPPORT: c_int = 122;
 #[cfg(any(ossl110, libressl261))]
@@ -359,6 +361,8 @@ pub const SSL_CTRL_SET_MAX_PROTO_VERSION: c_int = 124;
 pub const SSL_CTRL_GET_MIN_PROTO_VERSION: c_int = 130;
 #[cfg(any(ossl110g, libressl270))]
 pub const SSL_CTRL_GET_MAX_PROTO_VERSION: c_int = 131;
+#[cfg(ossl300)]
+pub const SSL_CTRL_GET_TMP_KEY: c_int = 133;
 
 pub unsafe fn SSL_CTX_set_tmp_dh(ctx: *mut SSL_CTX, dh: *mut DH) -> c_long {
     SSL_CTX_ctrl(ctx, SSL_CTRL_SET_TMP_DH, 0, dh as *mut c_void)
@@ -506,6 +510,17 @@ cfg_if! {
         }
     }
 }
+cfg_if! {
+    if #[cfg(ossl300)] {
+        pub unsafe fn SSL_get_peer_tmp_key(ssl: *mut SSL, key: *mut *mut EVP_PKEY) -> c_long {
+            SSL_ctrl(ssl, SSL_CTRL_GET_PEER_TMP_KEY, 0, key as *mut c_void)
+        }
+
+        pub unsafe fn SSL_get_tmp_key(ssl: *mut SSL, key: *mut *mut EVP_PKEY) -> c_long {
+            SSL_ctrl(ssl, SSL_CTRL_GET_TMP_KEY, 0, key as *mut c_void)
+        }
+    }
+}
 
 #[cfg(ossl111)]
 pub const SSL_CLIENT_HELLO_SUCCESS: c_int = 1;

openssl/src/lib.rs

@@ -125,6 +125,8 @@
 pub use ffi::init;
 
 use libc::c_int;
+#[cfg(ossl300)]
+use libc::c_long;
 
 use crate::error::ErrorStack;
 
@@ -212,6 +214,19 @@ fn cvt(r: c_int) -> Result<c_int, ErrorStack> {
     }
 }
 
+// cvt_long is currently only used in functions that require openssl >= 3.0.0,
+// so this cfg statement is used to avoid "unused function" errors when
+// compiling with openssl < 3.0.0
+#[inline]
+#[cfg(ossl300)]
+fn cvt_long(r: c_long) -> Result<c_long, ErrorStack> {
+    if r <= 0 {
+        Err(ErrorStack::get())
+    } else {
+        Ok(r)
+    }
+}
+
 #[inline]
 fn cvt_n(r: c_int) -> Result<c_int, ErrorStack> {
     if r < 0 {

openssl/src/ssl/mod.rs

@@ -57,6 +57,8 @@
 //!     }
 //! }
 //! ```
+#[cfg(ossl300)]
+use crate::cvt_long;
 use crate::dh::{Dh, DhRef};
 #[cfg(all(ossl101, not(ossl110)))]
 use crate::ec::EcKey;
@@ -68,6 +70,8 @@ use crate::hash::MessageDigest;
 #[cfg(any(ossl110, libressl270))]
 use crate::nid::Nid;
 use crate::pkey::{HasPrivate, PKeyRef, Params, Private};
+#[cfg(ossl300)]
+use crate::pkey::{PKey, Public};
 use crate::srtp::{SrtpProtectionProfile, SrtpProtectionProfileRef};
 use crate::ssl::bio::BioMethod;
 use crate::ssl::callbacks::*;
@@ -3445,6 +3449,38 @@ impl SslRef {
     pub fn security_level(&self) -> u32 {
         unsafe { ffi::SSL_get_security_level(self.as_ptr()) as u32 }
     }
+
+    /// Get the temporary key provided by the peer that is used during key
+    /// exchange.
+    // We use an owned value because EVP_KEY free need to be called when it is
+    // dropped
+    #[corresponds(SSL_get_peer_tmp_key)]
+    #[cfg(ossl300)]
+    pub fn peer_tmp_key(&self) -> Result<PKey<Public>, ErrorStack> {
+        unsafe {
+            let mut key = ptr::null_mut();
+            match cvt_long(ffi::SSL_get_peer_tmp_key(self.as_ptr(), &mut key)) {
+                Ok(_) => Ok(PKey::<Public>::from_ptr(key)),
+                Err(e) => Err(e),
+            }
+        }
+    }
+
+    /// Returns the temporary key from the local end of the connection that is
+    /// used during key exchange.
+    // We use an owned value because EVP_KEY free need to be called when it is
+    // dropped
+    #[corresponds(SSL_get_tmp_key)]
+    #[cfg(ossl300)]
+    pub fn tmp_key(&self) -> Result<PKey<Private>, ErrorStack> {
+        unsafe {
+            let mut key = ptr::null_mut();
+            match cvt_long(ffi::SSL_get_tmp_key(self.as_ptr(), &mut key)) {
+                Ok(_) => Ok(PKey::<Private>::from_ptr(key)),
+                Err(e) => Err(e),
+            }
+        }
+    }
 }
 
 /// An SSL stream midway through the handshake process.

openssl/src/ssl/test/mod.rs

@@ -19,7 +19,7 @@ use crate::error::ErrorStack;
 use crate::hash::MessageDigest;
 #[cfg(not(boringssl))]
 use crate::ocsp::{OcspResponse, OcspResponseStatus};
-use crate::pkey::PKey;
+use crate::pkey::{Id, PKey};
 use crate::srtp::SrtpProfileId;
 use crate::ssl::test::server::Server;
 #[cfg(any(ossl110, ossl111, libressl261))]
@@ -322,6 +322,56 @@ fn state() {
     );
 }
 
+// when a connection uses ECDHE P-384 key exchange, then the temp key APIs
+// return P-384 keys, and the peer and local keys are different.
+#[test]
+#[cfg(ossl300)]
+fn peer_tmp_key_p384() {
+    let mut server = Server::builder();
+    server.ctx().set_groups_list("P-384").unwrap();
+    let server = server.build();
+    let s = server.client().connect();
+    let peer_temp = s.ssl().peer_tmp_key().unwrap();
+    assert_eq!(peer_temp.id(), Id::EC);
+    assert_eq!(peer_temp.bits(), 384);
+
+    let local_temp = s.ssl().tmp_key().unwrap();
+    assert_eq!(local_temp.id(), Id::EC);
+    assert_eq!(local_temp.bits(), 384);
+
+    assert_ne!(
+        peer_temp.ec_key().unwrap().public_key_to_der().unwrap(),
+        local_temp.ec_key().unwrap().public_key_to_der().unwrap(),
+    );
+}
+
+// when a connection uses RSA key exchange, then the peer (server) temp key is
+// an Error because there is no temp key, and the local (client) temp key is the
+// temp key sent in the initial key share.
+#[test]
+#[cfg(ossl300)]
+fn peer_tmp_key_rsa() {
+    let mut server = Server::builder();
+    server.ctx().set_cipher_list("RSA").unwrap();
+    // RSA key exchange is not allowed in TLS 1.3, so force the connection
+    // to negotiate TLS 1.2
+    server
+        .ctx()
+        .set_max_proto_version(Some(SslVersion::TLS1_2))
+        .unwrap();
+    let server = server.build();
+    let mut client = server.client();
+    client.ctx().set_groups_list("P-521").unwrap();
+    let s = client.connect();
+    let peer_temp = s.ssl().peer_tmp_key();
+    assert!(peer_temp.is_err());
+
+    // this is the temp key that the client sent in the initial key share
+    let local_temp = s.ssl().tmp_key().unwrap();
+    assert_eq!(local_temp.id(), Id::EC);
+    assert_eq!(local_temp.bits(), 521);
+}
+
 /// Tests that when both the client as well as the server use SRTP and their
 /// lists of supported protocols have an overlap -- with only ONE protocol
 /// being valid for both.