gpg: Set a limit of 5 to the number of keys imported from the WKD.

* g10/import.c (import): Limit the number of considered keys to 5.
(import_one): Return the first fingerprint in case of WKD.
--

The Web Key Directory should carry only one key.  However, some
providers like to put old or expired keys also into the WKD.  I don't
thunk that this is a good idea but I heard claims that this is needed
for them to migrate existing key data bases.

This patch puts a limit on 5 on it (we had none right now) and also
fixes the issue that gpg could not work immediately with the requested
key because the code uses the fingerprint of the key to use the
imported key.  Now the first key is used.  On a second try (w/o
accessing the WKD) the regular key selection mechanism would be in
effect.  I think this is the most conservative approach.  Let's see
whether it helps.

Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit e9fcb0361ab4ef1f6fb0ea235f1b15667932aba2)

Gbp-Pq: Topic from-2.2.16
Gbp-Pq: Name gpg-Set-a-limit-of-5-to-the-number-of-keys-imported-from-.patch

diff --git a/g10/import.c b/g10/import.c
index aeab4e0d5d6aa81b646ebba476ad87d4e71aba80..3c8d0fed9308dd459e8d4e7adee17d9d90d7c0ed 100644 (file)
--- a/g10/import.c
+++ b/g10/import.c
@@ -665,6 +665,18 @@ import (ctrl_t ctrl, IOBUF inp, const char* fname,struct import_stats_s *stats,
 
       if (!(++stats->count % 100) && !opt.quiet)
         log_info (_("%lu keys processed so far\n"), stats->count );
+
+      if (origin == KEYORG_WKD && stats->count >= 5)
+        {
+          /* We limit the number of keys _received_ from the WKD to 5.
+           * In fact there should be only one key but some sites want
+           * to store a few expired keys there also.  gpg's key
+           * selection will later figure out which key to use.  Note
+           * that for WKD we always return the fingerprint of the
+           * first imported key.  */
+          log_info ("import from WKD stopped after %d keys\n", 5);
+          break;
+        }
     }
   stats->v3keys += v3keys;
   if (rc == -1)
@@ -2183,14 +2195,19 @@ import_one (ctrl_t ctrl,
          fingerprint of the key in all cases.  */
       if (fpr)
         {
-          xfree (*fpr);
           /* Note that we need to compare against 0 here because
              COUNT gets only incremented after returning from this
              function.  */
           if (!stats->count)
-            *fpr = fingerprint_from_pk (pk, NULL, fpr_len);
-          else
-            *fpr = NULL;
+            {
+              xfree (*fpr);
+              *fpr = fingerprint_from_pk (pk, NULL, fpr_len);
+            }
+          else if (origin != KEYORG_WKD)
+            {
+              xfree (*fpr);
+              *fpr = NULL;
+            }
         }
     }