From e573e6188dada4d70f6897aa2fda3c3af8c50441 Mon Sep 17 00:00:00 2001
From: "Neal H. Walfield" <neal@g10code.com>
Date: Mon, 14 Dec 2015 12:05:29 +0100
Subject: [PATCH] gpg: Fix --default-key checks.

* g10/getkey.c (parse_def_secret_key): Don't just check if a secret
key is available for the public key, also consider subkeys.  Also
check that the key has the signing capability, is not revoked, is not
expired and is not disabled.  Print a warning if there was a least one
value passed to --default-key and all were ignored.

--
Signed-off-by: Neal H. Walfield <neal@g10code.com>
Regression-due-to: e16d7168
---
 g10/getkey.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 59 insertions(+), 3 deletions(-)

diff --git a/g10/getkey.c b/g10/getkey.c
index b09d967f0..16986cb94 100644
--- a/g10/getkey.c
+++ b/g10/getkey.c
@@ -1168,6 +1168,7 @@ parse_def_secret_key (ctrl_t ctrl)
       gpg_error_t err;
       KEYDB_SEARCH_DESC desc;
       KBNODE kb;
+      KBNODE node;
 
       err = classify_user_id (t->d, &desc, 1);
       if (err)
@@ -1208,16 +1209,71 @@ parse_def_secret_key (ctrl_t ctrl)
           continue;
         }
 
-      err = agent_probe_secret_key (ctrl, kb->pkt->pkt.public_key);
+      merge_selfsigs (kb);
+
+      err = gpg_error (GPG_ERR_NO_SECKEY);
+      node = kb;
+      do
+        {
+          PKT_public_key *pk = node->pkt->pkt.public_key;
+
+          /* Check that the key has the signing capability.  */
+          if (! (pk->pubkey_usage & PUBKEY_USAGE_SIG))
+            continue;
+
+          /* Check if the key is valid.  */
+          if (pk->flags.revoked)
+            {
+              if (DBG_LOOKUP)
+                log_debug (_("not using %s as default key, %s"), "revoked");
+              continue;
+            }
+          if (pk->has_expired)
+            {
+              if (DBG_LOOKUP)
+                log_debug (_("not using %s as default key, %s"), "expired");
+              continue;
+            }
+          if (pk_is_disabled (pk))
+            {
+              if (DBG_LOOKUP)
+                log_debug (_("not using %s as default key, %s"), "disabled");
+              continue;
+            }
+
+          err = agent_probe_secret_key (ctrl, pk);
+          if (! err)
+            /* This is a valid key.  */
+            break;
+        }
+      while ((node = find_next_kbnode (node, PKT_PUBLIC_SUBKEY)));
+
       release_kbnode (kb);
-      if (! err)
+      if (err)
+        {
+          if (! warned && ! opt.quiet)
+            {
+              if (gpg_err_code (err) == GPG_ERR_NO_SECKEY)
+                log_info (_("Warning: not using '%s' as default key: %s.\n"),
+                          t->d, gpg_strerror (err));
+              else
+                log_info (_("Warning: not using '%s' as default key: no secret key available: %s\n"),
+                          t->d, gpg_strerror (err));
+            }
+        }
+      else
         {
           if (! warned)
-            log_info (_("using \"%s\" as default secret key\n"), t->d);
+            log_info (_("using \"%s\" as default secret key for signing\n"),
+                      t->d);
           break;
         }
     }
 
+  if (! warned && opt.def_secret_key && ! t)
+    log_info (_("all values passed to '%s' ignored.\n"),
+              "--default-key");
+
   warned = 1;
 
   if (hd)