openpgp: take ownership of KeyFlags bitfield

- Make `generate_key` polymorphic over `AsRef<KeyFlags>`.

- Since `set_key_flags` requires ownership of the key flags, it should
  take ownership rather than borrowing and cloning the them.
  See https://rust-lang.github.io/api-guidelines/flexibility.html#caller-decides-where-to-copy-and-place-data-c-caller-control .

- See #616.

9 files changed, 32 insertions, 24 deletions

diff --git a/openpgp/src/cert.rs b/openpgp/src/cert.rs
index 1202ae5f..2e25ad62 100644
--- a/openpgp/src/cert.rs
+++ b/openpgp/src/cert.rs
@@ -4434,7 +4434,7 @@ mod test {
         let (bind1, rev1, bind2, rev2) = {
             let bind1 = signature::SignatureBuilder::new(SignatureType::DirectKey)
                 .set_features(&Features::sequoia()).unwrap()
-                .set_key_flags(&KeyFlags::empty()).unwrap()
+                .set_key_flags(KeyFlags::empty()).unwrap()
                 .set_signature_creation_time(t1).unwrap()
                 .set_key_validity_period(Some(time::Duration::new(10 * 52 * 7 * 24 * 60 * 60, 0))).unwrap()
                 .set_preferred_hash_algorithms(vec![HashAlgorithm::SHA512]).unwrap()
@@ -4448,7 +4448,7 @@ mod test {
 
             let bind2 = signature::SignatureBuilder::new(SignatureType::DirectKey)
                 .set_features(&Features::sequoia()).unwrap()
-                .set_key_flags(&KeyFlags::empty()).unwrap()
+                .set_key_flags(KeyFlags::empty()).unwrap()
                 .set_signature_creation_time(t3).unwrap()
                 .set_key_validity_period(Some(time::Duration::new(10 * 52 * 7 * 24 * 60 * 60, 0))).unwrap()
                 .set_preferred_hash_algorithms(vec![HashAlgorithm::SHA512]).unwrap()
@@ -5117,7 +5117,7 @@ Pu1xwz57O4zo1VYf6TqHJzVC3OMvMUM2hhdecMUe5x6GorNaj6g=
             for i in 0..N {
                 let binding = signature::SignatureBuilder::new(SignatureType::DirectKey)
                     .set_features(&Features::sequoia()).unwrap()
-                    .set_key_flags(&KeyFlags::empty()).unwrap()
+                    .set_key_flags(KeyFlags::empty()).unwrap()
                     .set_signature_creation_time(t1).unwrap()
                     // Vary this...
                     .set_key_validity_period(Some(
@@ -5383,7 +5383,7 @@ Pu1xwz57O4zo1VYf6TqHJzVC3OMvMUM2hhdecMUe5x6GorNaj6g=
             key::Key4::generate_ecc(false, Curve::Cv25519)?.into();
         let subkey_pub = subkey_sec.clone().take_secret().0;
         let builder = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-            .set_key_flags(&KeyFlags::empty()
+            .set_key_flags(KeyFlags::empty()
                            .set_transport_encryption())?;
         let binding = subkey_sec.bind(&mut primary_pair, &cert, builder)?;
 
diff --git a/openpgp/src/cert/bindings.rs b/openpgp/src/cert/bindings.rs
index 5da9360d..34b99d63 100644
--- a/openpgp/src/cert/bindings.rs
+++ b/openpgp/src/cert/bindings.rs
@@ -58,7 +58,7 @@ impl<P: key::KeyParts> Key<P, key::SubordinateRole> {
     ///     Key4::generate_ecc(false, Curve::Cv25519)?
     ///     .into();
     /// let builder = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-    ///     .set_key_flags(&flags)?;
+    ///     .set_key_flags(flags.clone())?;
     /// let binding = subkey.bind(&mut keypair, &cert, builder)?;
     ///
     /// // Now merge the key and binding signature into the Cert.
diff --git a/openpgp/src/cert/builder.rs b/openpgp/src/cert/builder.rs
index d30cee59..6d79a910 100644
--- a/openpgp/src/cert/builder.rs
+++ b/openpgp/src/cert/builder.rs
@@ -73,9 +73,10 @@ impl Default for CipherSuite {
 }
 
 impl CipherSuite {
-    fn generate_key<R>(self, flags: &KeyFlags)
+    fn generate_key<K, R>(self, flags: K)
         -> Result<Key<key::SecretParts, R>>
-        where R: key::KeyRole
+        where R: key::KeyRole,
+              K: AsRef<KeyFlags>,
     {
         use crate::types::Curve;
 
@@ -88,6 +89,7 @@ impl CipherSuite {
                 Key4::generate_rsa(4096),
             CipherSuite::Cv25519 | CipherSuite::P256 |
             CipherSuite::P384 | CipherSuite::P521 => {
+                let flags = flags.as_ref();
                 let sign = flags.for_certification() || flags.for_signing()
                     || flags.for_authentication();
                 let encrypt = flags.for_transport_encryption()
@@ -1038,7 +1040,7 @@ impl CertBuilder<'_> {
                 // GnuPG wants at least a 512-bit hash for P521 keys.
                 .set_hash_algo(HashAlgorithm::SHA512)
                 .set_features(&Features::sequoia())?
-                .set_key_flags(flags)?
+                .set_key_flags(flags.clone())?
                 .set_key_validity_period(blueprint.validity.or(self.primary.validity))?;
 
             if flags.for_certification() || flags.for_signing() {
@@ -1081,13 +1083,13 @@ impl CertBuilder<'_> {
     {
         let mut key = self.primary.ciphersuite
             .unwrap_or(self.ciphersuite)
-            .generate_key(&KeyFlags::empty().set_certification())?;
+            .generate_key(KeyFlags::empty().set_certification())?;
         key.set_creation_time(creation_time)?;
         let mut sig = signature::SignatureBuilder::new(SignatureType::DirectKey)
             // GnuPG wants at least a 512-bit hash for P521 keys.
             .set_hash_algo(HashAlgorithm::SHA512)
             .set_features(&Features::sequoia())?
-            .set_key_flags(&self.primary.flags)?
+            .set_key_flags(self.primary.flags.clone())?
             .set_signature_creation_time(creation_time)?
             .set_key_validity_period(self.primary.validity)?
             .set_preferred_hash_algorithms(vec![
diff --git a/openpgp/src/packet/signature.rs b/openpgp/src/packet/signature.rs
index ddc80214..3819bb18 100644
--- a/openpgp/src/packet/signature.rs
+++ b/openpgp/src/packet/signature.rs
@@ -1067,7 +1067,7 @@ impl SignatureBuilder {
     /// let mut sk_signer = subkey.clone().into_keypair()?;
     ///
     /// let sig = SignatureBuilder::new(SignatureType::SubkeyBinding)
-    ///     .set_key_flags(&KeyFlags::empty().set_transport_encryption())?
+    ///     .set_key_flags(KeyFlags::empty().set_transport_encryption())?
     ///     .sign_subkey_binding(&mut pk_signer, None, &subkey)?;
     ///
     /// let cert = cert.insert_packets(vec![Packet::SecretSubkey(subkey),
@@ -1211,7 +1211,7 @@ impl SignatureBuilder {
     /// let mut sk_signer = subkey.clone().into_keypair()?;
     ///
     /// let sig = SignatureBuilder::new(SignatureType::SubkeyBinding)
-    ///     .set_key_flags(&KeyFlags::empty().set_signing())?
+    ///     .set_key_flags(KeyFlags::empty().set_signing())?
     ///     // The backsig.  This is essential for subkeys that create signatures!
     ///     .set_embedded_signature(
     ///         SignatureBuilder::new(SignatureType::PrimaryKeyBinding)
diff --git a/openpgp/src/packet/signature/subpacket.rs b/openpgp/src/packet/signature/subpacket.rs
index ae5ccf1d..2d2c5506 100644
--- a/openpgp/src/packet/signature/subpacket.rs
+++ b/openpgp/src/packet/signature/subpacket.rs
@@ -6020,7 +6020,7 @@ impl signature::SignatureBuilder {
     ///     = Key4::generate_ecc(false, Curve::Cv25519)?
     ///         .into();
     /// let builder = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-    ///     .set_key_flags(&KeyFlags::empty().set_storage_encryption())?;
+    ///     .set_key_flags(KeyFlags::empty().set_storage_encryption())?;
     /// let binding = subkey.bind(&mut signer, &cert, builder)?;
     ///
     /// // Now merge the key and binding signature into the Cert.
@@ -6032,9 +6032,9 @@ impl signature::SignatureBuilder {
     /// #            1);
     /// # Ok(()) }
     /// ```
-    pub fn set_key_flags(mut self, flags: &KeyFlags) -> Result<Self> {
+    pub fn set_key_flags(mut self, flags: KeyFlags) -> Result<Self> {
         self.hashed_area.replace(Subpacket::new(
-            SubpacketValue::KeyFlags(flags.clone()),
+            SubpacketValue::KeyFlags(flags),
             true)?)?;
 
         Ok(self)
@@ -6348,7 +6348,7 @@ impl signature::SignatureBuilder {
     ///
     /// // Create the binding signature.
     /// let sig = SignatureBuilder::new(SignatureType::SubkeyBinding)
-    ///     .set_key_flags(&KeyFlags::empty().set_signing())?
+    ///     .set_key_flags(KeyFlags::empty().set_signing())?
     ///     // And, the backsig.  This is essential for subkeys that create signatures!
     ///     .set_embedded_signature(
     ///         SignatureBuilder::new(SignatureType::PrimaryKeyBinding)
@@ -6982,7 +6982,7 @@ fn accessors() {
     let key_flags = KeyFlags::empty()
         .set_certification()
         .set_signing();
-    sig = sig.set_key_flags(&key_flags).unwrap();
+    sig = sig.set_key_flags(key_flags.clone()).unwrap();
     let sig_ =
         sig.clone().sign_hash(&mut keypair, hash.clone()).unwrap();
     assert_eq!(sig_.key_flags().unwrap(), key_flags);
diff --git a/openpgp/src/policy.rs b/openpgp/src/policy.rs
index 8a33a8c2..cc268d17 100644
--- a/openpgp/src/policy.rs
+++ b/openpgp/src/policy.rs
@@ -1511,7 +1511,7 @@ mod test {
         let subkey: key::SecretSubkey
             = Key4::generate_rsa(4096)?.into();
         let binding = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-            .set_key_flags(&KeyFlags::empty().set_transport_encryption())?
+            .set_key_flags(KeyFlags::empty().set_transport_encryption())?
             .sign_subkey_binding(&mut pk.clone().into_keypair()?,
                                  pk.parts_as_public(), &subkey)?;
 
@@ -1534,7 +1534,7 @@ mod test {
         let subkey: key::SecretSubkey
             = key::Key4::generate_ecc(true, Curve::Ed25519)?.into();
         let binding = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-            .set_key_flags(&KeyFlags::empty().set_transport_encryption())?
+            .set_key_flags(KeyFlags::empty().set_transport_encryption())?
             .sign_subkey_binding(&mut pk.clone().into_keypair()?,
                                  pk.parts_as_public(), &subkey)?;
 
diff --git a/openpgp/src/serialize/cert.rs b/openpgp/src/serialize/cert.rs
index 32f8433b..fca26277 100644
--- a/openpgp/src/serialize/cert.rs
+++ b/openpgp/src/serialize/cert.rs
@@ -901,7 +901,7 @@ mod test {
             &mut keypair, &cert,
             signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
                 .set_key_flags(
-                    &KeyFlags::empty().set_transport_encryption())
+                    KeyFlags::empty().set_transport_encryption())
                 .unwrap()
                 .set_exportable_certification(false).unwrap()).unwrap();
 
diff --git a/openpgp/src/types/key_flags.rs b/openpgp/src/types/key_flags.rs
index 3909dbfe..cca9ac92 100644
--- a/openpgp/src/types/key_flags.rs
+++ b/openpgp/src/types/key_flags.rs
@@ -143,6 +143,12 @@ impl BitOr for &KeyFlags {
     }
 }
 
+impl AsRef<KeyFlags> for KeyFlags {
+    fn as_ref(&self) -> &KeyFlags {
+        self
+    }
+}
+
 impl KeyFlags {
     /// Creates a new instance from `bits`.
     pub fn new<B: AsRef<[u8]>>(bits: B) -> Self {
diff --git a/sqv/tests/revoked-key.rs b/sqv/tests/revoked-key.rs
index 404092e1..fcc35f4f 100644
--- a/sqv/tests/revoked-key.rs
+++ b/sqv/tests/revoked-key.rs
@@ -315,7 +315,7 @@ fn create_key() {
     // 1st direct key signature valid from t1 on
     let mut b = signature::SignatureBuilder::new(SignatureType::DirectKey)
         .set_features(&Features::sequoia()).unwrap()
-        .set_key_flags(&KeyFlags::empty()
+        .set_key_flags(KeyFlags::empty()
                        .set_signing().set_certification()).unwrap()
         .set_signature_creation_time(t1).unwrap()
         .set_preferred_hash_algorithms(vec![HashAlgorithm::SHA512])
@@ -324,7 +324,7 @@ fn create_key() {
 
     // 1st subkey binding signature valid from t_sk_binding on
     b = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-        .set_key_flags(&KeyFlags::empty().set_signing()).unwrap()
+        .set_key_flags(KeyFlags::empty().set_signing()).unwrap()
         .set_signature_creation_time(t_sk_binding).unwrap()
         .set_embedded_signature(
             signature::SignatureBuilder::new(SignatureType::PrimaryKeyBinding)
@@ -336,7 +336,7 @@ fn create_key() {
     // 2nd direct key signature valid from t3 on
     b = signature::SignatureBuilder::new(SignatureType::DirectKey)
         .set_features(&Features::sequoia()).unwrap()
-        .set_key_flags(&KeyFlags::empty()
+        .set_key_flags(KeyFlags::empty()
                        .set_signing().set_certification()).unwrap()
         .set_signature_creation_time(t3).unwrap()
         .set_preferred_hash_algorithms(vec![HashAlgorithm::SHA512])
@@ -345,7 +345,7 @@ fn create_key() {
 
     // 2nd subkey binding signature valid from t3 on
     let mut b = signature::SignatureBuilder::new(SignatureType::SubkeyBinding)
-        .set_key_flags(&KeyFlags::empty().set_signing()).unwrap()
+        .set_key_flags(KeyFlags::empty().set_signing()).unwrap()
         .set_signature_creation_time(t3).unwrap()
         .set_embedded_signature(
             signature::SignatureBuilder::new(SignatureType::PrimaryKeyBinding)