gpg: Prepare to accept shorter OIDs for ed25519 and cv25519.

* common/openpgp-oid.c (oidtable): Add them.
(oid_ed25519_v5, oid_cv25519_v5): New.
(openpgp_oidbuf_is_ed25519): Take new OID in account.
(openpgp_oidbuf_is_cv25519): Ditto.
--

ed25519 is used in GnuPG and other implementations since 2015 and thus
we can't simply switch to the shorter OIDs.  However, we have not
widely used them with v5 keys (only ed448 forced the use of v5) and
thus it might be possible to use the new OIDs with v5 keys.

Note that Libgcrypt supports the new OIDs even in 1.8.

1 files changed, 20 insertions, 6 deletions

diff --git a/common/openpgp-oid.c b/common/openpgp-oid.c
index f0460b068..510e09f4a 100644
--- a/common/openpgp-oid.c
+++ b/common/openpgp-oid.c
@@ -48,6 +48,8 @@ static struct {
 
   { "Curve25519", "1.3.6.1.4.1.3029.1.5.1", 255, "cv25519", PUBKEY_ALGO_ECDH },
   { "Ed25519",    "1.3.6.1.4.1.11591.15.1", 255, "ed25519", PUBKEY_ALGO_EDDSA },
+  { "Curve25519", "1.3.101.110",            255, "cv25519", PUBKEY_ALGO_ECDH },
+  { "Ed25519",    "1.3.101.112",            255, "ed25519", PUBKEY_ALGO_EDDSA },
   { "X448",       "1.3.101.111",            448, "cv448",   PUBKEY_ALGO_ECDH },
   { "Ed448",      "1.3.101.113",            456, "ed448",   PUBKEY_ALGO_EDDSA },
 
@@ -65,13 +67,17 @@ static struct {
 };
 
 
-/* The OID for Curve Ed25519 in OpenPGP format.  */
+/* The OID for Curve Ed25519 in OpenPGP format.  The shorter v5
+ * variant may only be used with v5 keys.  */
 static const char oid_ed25519[] =
   { 0x09, 0x2b, 0x06, 0x01, 0x04, 0x01, 0xda, 0x47, 0x0f, 0x01 };
+static const char oid_ed25519_v5[] = { 0x03, 0x2b, 0x65, 0x70 };
 
-/* The OID for Curve25519 in OpenPGP format.  */
+/* The OID for Curve25519 in OpenPGP format.  The shorter v5
+ * variant may only be used with v5 keys.  */
 static const char oid_cv25519[] =
   { 0x0a, 0x2b, 0x06, 0x01, 0x04, 0x01, 0x97, 0x55, 0x01, 0x05, 0x01 };
+static const char oid_cv25519_v5[] = { 0x03, 0x2b, 0x65, 0x6e };
 
 /* The OID for X448 in OpenPGP format. */
 /*
@@ -321,8 +327,12 @@ openpgp_oid_to_str (gcry_mpi_t a)
 int
 openpgp_oidbuf_is_ed25519 (const void *buf, size_t len)
 {
-  return (buf && len == DIM (oid_ed25519)
-          && !memcmp (buf, oid_ed25519, DIM (oid_ed25519)));
+  if (!buf)
+    return 0;
+  return ((len == DIM (oid_ed25519)
+           && !memcmp (buf, oid_ed25519, DIM (oid_ed25519)))
+          || (len == DIM (oid_ed25519_v5)
+              && !memcmp (buf, oid_ed25519_v5, DIM (oid_ed25519_v5))));
 }
 
 
@@ -345,8 +355,12 @@ openpgp_oid_is_ed25519 (gcry_mpi_t a)
 int
 openpgp_oidbuf_is_cv25519 (const void *buf, size_t len)
 {
-  return (buf && len == DIM (oid_cv25519)
-          && !memcmp (buf, oid_cv25519, DIM (oid_cv25519)));
+  if (!buf)
+    return 0;
+  return ((len == DIM (oid_cv25519)
+           && !memcmp (buf, oid_cv25519, DIM (oid_cv25519)))
+          || (len == DIM (oid_cv25519_v5)
+              && !memcmp (buf, oid_cv25519_v5, DIM (oid_cv25519_v5))));
 }