From acafa695e1e7998b892a6a621ef06d57bbc82722 Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Wed, 2 Dec 2020 11:11:47 +0100
Subject: [PATCH] kbx: Better error message in case of a crippled Libgcrypt.

* kbx/keybox-openpgp.c (keygrip_from_keyparm): Detect missing curve.
---
 kbx/keybox-openpgp.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kbx/keybox-openpgp.c b/kbx/keybox-openpgp.c
index 6d6ed77dc..8ded6839c 100644
--- a/kbx/keybox-openpgp.c
+++ b/kbx/keybox-openpgp.c
@@ -240,8 +240,16 @@ keygrip_from_keyparm (int algo, struct keyparm_s *kp, unsigned char *grip)
 
   if (!err && !gcry_pk_get_keygrip (s_pkey, grip))
     {
-      log_info ("kbx: error computing keygrip\n");
-      err = gpg_error (GPG_ERR_GENERAL);
+      /* Some Linux distributions remove certain curves from Libgcrypt
+       * but not from GnuPG and thus the keygrip can't be computed.
+       * Emit a better error message for this case.  */
+      if (!gcry_pk_get_curve (s_pkey, 0, NULL))
+        err = gpg_error (GPG_ERR_UNKNOWN_CURVE);
+      else
+        {
+          log_info ("kbx: error computing keygrip\n");
+          err = gpg_error (GPG_ERR_GENERAL);
+        }
     }
 
   gcry_sexp_release (s_pkey);