From 913904754ddd585d93522bc45e8d9e830d278f9a Mon Sep 17 00:00:00 2001
From: Justus Winter <justus@sequoia-pgp.org>
Date: Wed, 1 Mar 2023 16:25:59 +0100
Subject: openpgp: Add support for brainpoolP384r1.

  - One of the brainpool curves was not included in our enum Curve,
    because at the time we implemented ECC support, it wasn't part of
    the RFC4880bis document.

  - Unfortunately, we failed to mark enum Curve as non-exhaustive, so
    we cannot add a variant without breaking the API.

  - We can, however, support the curve by matching on its OID.
---
 openpgp/src/types/mod.rs | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

(limited to 'openpgp/src/types/mod.rs')

diff --git a/openpgp/src/types/mod.rs b/openpgp/src/types/mod.rs
index 863880e5..698b65d1 100644
--- a/openpgp/src/types/mod.rs
+++ b/openpgp/src/types/mod.rs
@@ -365,6 +365,13 @@ pub enum Curve {
     /// Unknown curve.
     Unknown(Box<[u8]>),
 }
+impl Curve {
+    /// Hack!  Curve is not non-exhaustive, so we cannot easily add
+    /// a variant.
+    pub(crate) fn is_brainpoolp384(&self) -> bool {
+        self.oid() == BRAINPOOL_P384_OID
+    }
+}
 assert_send_and_sync!(Curve);
 
 impl Curve {
@@ -398,6 +405,7 @@ impl Curve {
             NistP384 => Some(384),
             NistP521 => Some(521),
             BrainpoolP256 => Some(256),
+            Unknown(_) if self.is_brainpoolp384() => Some(384),
             BrainpoolP512 => Some(512),
             Ed25519 => Some(256),
             Cv25519 => Some(256),
@@ -455,6 +463,8 @@ impl fmt::Display for Curve {
                 NistP384 => f.write_str("NIST curve P-384"),
                 NistP521 => f.write_str("NIST curve P-521"),
                 BrainpoolP256 => f.write_str("brainpoolP256r1"),
+                Unknown(_) if self.is_brainpoolp384() =>
+                    f.write_str("brainpoolP384r1"),
                 BrainpoolP512 => f.write_str("brainpoolP512r1"),
                 Ed25519
                     => f.write_str("D.J. Bernstein's \"Twisted\" Edwards curve Ed25519"),
@@ -469,6 +479,8 @@ impl fmt::Display for Curve {
                 NistP384 => f.write_str("NIST P-384"),
                 NistP521 => f.write_str("NIST P-521"),
                 BrainpoolP256 => f.write_str("brainpoolP256r1"),
+                Unknown(_) if self.is_brainpoolp384() =>
+                    f.write_str("brainpoolP384r1"),
                 BrainpoolP512 => f.write_str("brainpoolP512r1"),
                 Ed25519
                     => f.write_str("Ed25519"),
@@ -486,6 +498,8 @@ const NIST_P384_OID: &[u8] = &[0x2B, 0x81, 0x04, 0x00, 0x22];
 const NIST_P521_OID: &[u8] = &[0x2B, 0x81, 0x04, 0x00, 0x23];
 const BRAINPOOL_P256_OID: &[u8] =
     &[0x2B, 0x24, 0x03, 0x03, 0x02, 0x08, 0x01, 0x01, 0x07];
+const BRAINPOOL_P384_OID: &[u8] =
+    &[0x2B, 0x24, 0x03, 0x03, 0x02, 0x08, 0x01, 0x01, 0x0B];
 const BRAINPOOL_P512_OID: &[u8] =
     &[0x2B, 0x24, 0x03, 0x03, 0x02, 0x08, 0x01, 0x01, 0x0D];
 const ED25519_OID: &[u8] =
@@ -513,6 +527,7 @@ impl Curve {
             NIST_P384_OID => Curve::NistP384,
             NIST_P521_OID => Curve::NistP521,
             BRAINPOOL_P256_OID => Curve::BrainpoolP256,
+            BRAINPOOL_P384_OID => Curve::Unknown(BRAINPOOL_P384_OID.into()),
             BRAINPOOL_P512_OID => Curve::BrainpoolP512,
             ED25519_OID => Curve::Ed25519,
             CV25519_OID => Curve::Cv25519,
@@ -568,6 +583,7 @@ impl Curve {
             Curve::NistP384 => Ok(384),
             Curve::NistP521 => Ok(521),
             Curve::BrainpoolP256 => Ok(256),
+            Curve::Unknown(_) if self.is_brainpoolp384() => Ok(384),
             Curve::BrainpoolP512 => Ok(512),
             Curve::Ed25519 => Ok(256),
             Curve::Cv25519 => Ok(256),
@@ -596,15 +612,16 @@ impl Curve {
 #[cfg(test)]
 impl Arbitrary for Curve {
     fn arbitrary(g: &mut Gen) -> Self {
-        match u8::arbitrary(g) % 8 {
+        match u8::arbitrary(g) % 9 {
             0 => Curve::NistP256,
             1 => Curve::NistP384,
             2 => Curve::NistP521,
             3 => Curve::BrainpoolP256,
-            4 => Curve::BrainpoolP512,
-            5 => Curve::Ed25519,
-            6 => Curve::Cv25519,
-            7 => Curve::Unknown({
+            4 => Curve::Unknown(BRAINPOOL_P384_OID.into()),
+            5 => Curve::BrainpoolP512,
+            6 => Curve::Ed25519,
+            7 => Curve::Cv25519,
+            8 => Curve::Unknown({
                 let mut k = <Vec<u8>>::arbitrary(g);
                 k.truncate(255);
                 k.into_boxed_slice()
-- 
cgit v1.2.3