gpg: Implement the LDAP AKL method.

* g10/keyserver.c (keyserver_import_mbox): Add arg flags and change
callers.
(keyserver_import_ldap): Remove.  It has always returned a not
implemented error since 2.1.
* g10/getkey.c (get_pubkey_byname): Repurpose LDAP to do basically the
same as KEYSERVER.
--

The old LDAP mechanism to locate a server via SRV records has long
been gone (since 2014) due to the dropping of the keyserver helpers.
The new purpose better reflects reality and can be used in
environments where keys are provided by an in-house LDAP server.

(cherry picked from commit 068ebb6f1e)

doc/gpg.texi

@@ -1981,15 +1981,15 @@ list.  The default is "local,wkd".
   Locate a key using the Web Key Directory protocol.
 
   @item ldap
-  Using DNS Service Discovery, check the domain in question for any LDAP
+  Locate the key using the configured LDAP servers.  This method is
-  keyservers to use.  If this fails, attempt to locate the key using the
+  similar to the @code{keyserver} mechanism but always uses only LDAP
-  PGP Universal method of checking @samp{ldap://keys.(thedomain)}.
+  servers.
 
   @item ntds
   Locate the key using the Active Directory (Windows only).  This
   method also allows one to search by fingerprint using the command
   @option{--locate-external-key}.  Note that this mechanism is
-  actually a shortcut for the mechanism @samp{keyserver} but using
+  actually a shortcut for the mechanism @samp{ldap} using only
   "ldap:///" as the keyserver.
 
   @item keyserver

g10/getkey.c

@@ -1,7 +1,7 @@
 /* getkey.c -  Get a key from the database
  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
  *               2007, 2008, 2010  Free Software Foundation, Inc.
- * Copyright (C) 2015, 2016 g10 Code GmbH
+ * Copyright (C) 2015, 2016, 2024 g10 Code GmbH
  *
  * This file is part of GnuPG.
  *
@@ -17,6 +17,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
 #include <config.h>
@@ -1176,16 +1177,31 @@ get_pubkey_byname (ctrl_t ctrl, enum get_pubkey_modes mode,
 	      break;
 
 	    case AKL_LDAP:
-              if (is_fpr)
+	      if (!keyserver_any_configured (ctrl))
                 {
                   mechanism_string = "";
                   rc = GPG_ERR_NO_PUBKEY;
                 }
               else
                 {
-                  mechanism_string = "LDAP";
+                  mechanism_string = is_fpr? "ldap/fpr":"ldap/mbox";
                   glo_ctrl.in_auto_key_retrieve++;
-                  rc = keyserver_import_ldap (ctrl, name, &fpr, &fpr_len);
+                  if (is_fpr)
+                    rc = keyserver_import_fprint (ctrl,
+                                               fprbuf.u.fpr, fprbuf.fprlen,
+                                               opt.keyserver,
+                                               KEYSERVER_IMPORT_FLAG_LDAP);
+                  else
+                    rc = keyserver_import_mbox (ctrl, name, &fpr, &fpr_len,
+                                                opt.keyserver,
+                                                KEYSERVER_IMPORT_FLAG_LDAP);
+                  /* Map error codes because Dirmngr returns NO DATA
+                   * if the keyserver does not have the requested key.
+                   * It returns NO KEYSERVER if no LDAP keyservers are
+                   * configured.  */
+                  if (gpg_err_code (rc) == GPG_ERR_NO_DATA
+                      || gpg_err_code (rc) == GPG_ERR_NO_KEYSERVER)
+                    rc = gpg_error (GPG_ERR_NO_PUBKEY);
                   glo_ctrl.in_auto_key_retrieve--;
                 }
               break;
@@ -1227,7 +1243,7 @@ get_pubkey_byname (ctrl_t ctrl, enum get_pubkey_modes mode,
                   else
                     {
                       rc = keyserver_import_mbox (ctrl, name, &fpr, &fpr_len,
-                                                  opt.keyserver);
+                                                  opt.keyserver, 0);
                     }
 		  glo_ctrl.in_auto_key_retrieve--;
 		}
@@ -1258,7 +1274,7 @@ get_pubkey_byname (ctrl_t ctrl, enum get_pubkey_modes mode,
                 else
                   {
                     rc = keyserver_import_mbox (ctrl, name,
-                                                &fpr, &fpr_len, keyserver);
+                                                &fpr, &fpr_len, keyserver, 0);
                   }
 		glo_ctrl.in_auto_key_retrieve--;
 	      }

g10/gpg.c

@@ -4743,8 +4743,6 @@ main (int argc, char **argv)
             parse_auto_key_locate (DEFAULT_AKL_LIST);
           }
 	public_key_list (ctrl, sl, 1, cmd == aLocateExtKeys);
-
-
 	free_strlist (sl);
 	break;
 

g10/keyserver-internal.h

@@ -55,10 +55,9 @@ gpg_error_t keyserver_import_wkd (ctrl_t ctrl, const char *name,
                                   unsigned char **fpr, size_t *fpr_len);
 int keyserver_import_ntds (ctrl_t ctrl, const char *name,
                            unsigned char **fpr,size_t *fpr_len);
-int keyserver_import_mbox (ctrl_t ctrl, const char *mbox,
+gpg_error_t keyserver_import_mbox (ctrl_t ctrl, const char *mbox,
                                    unsigned char **fpr,size_t *fpr_len,
-                           struct keyserver_spec *keyserver);
+                                   struct keyserver_spec *keyserver,
-int keyserver_import_ldap (ctrl_t ctrl, const char *name,
+                                   unsigned int flags);
-                           unsigned char **fpr,size_t *fpr_len);
 
 #endif /* !_KEYSERVER_INTERNAL_H_ */

g10/keyserver.c

@@ -946,17 +946,17 @@ keyserver_any_configured (ctrl_t ctrl)
 
 
 /* Import all keys that exactly match MBOX */
-int
+gpg_error_t
 keyserver_import_mbox (ctrl_t ctrl, const char *mbox,
                        unsigned char **fpr, size_t *fprlen,
-                       struct keyserver_spec *keyserver)
+                       struct keyserver_spec *keyserver, unsigned int flags)
 {
   KEYDB_SEARCH_DESC desc = { 0 };
 
   desc.mode = KEYDB_SEARCH_MODE_MAIL;
   desc.u.name = mbox;
 
-  return keyserver_get (ctrl, &desc, 1, keyserver, 0, fpr, fprlen);
+  return keyserver_get (ctrl, &desc, 1, keyserver, flags, fpr, fprlen);
 }
 
 
@@ -1867,85 +1867,3 @@ keyserver_import_wkd (ctrl_t ctrl, const char *name, unsigned int flags,
   xfree (mbox);
   return err;
 }
-
-
-/* Import a key by name using LDAP */
-int
-keyserver_import_ldap (ctrl_t ctrl,
-                       const char *name, unsigned char **fpr, size_t *fprlen)
-{
-  (void)ctrl;
-  (void)name;
-  (void)fpr;
-  (void)fprlen;
-  return gpg_error (GPG_ERR_NOT_IMPLEMENTED); /*FIXME*/
-#if 0
-  char *domain;
-  struct keyserver_spec *keyserver;
-  strlist_t list=NULL;
-  int rc,hostlen=1;
-  struct srventry *srvlist=NULL;
-  int srvcount,i;
-  char srvname[MAXDNAME];
-
-  /* Parse out the domain */
-  domain=strrchr(name,'@');
-  if(!domain)
-    return GPG_ERR_GENERAL;
-
-  domain++;
-
-  keyserver=xmalloc_clear(sizeof(struct keyserver_spec));
-  keyserver->scheme=xstrdup("ldap");
-  keyserver->host=xmalloc(1);
-  keyserver->host[0]='\0';
-
-  snprintf(srvname,MAXDNAME,"_pgpkey-ldap._tcp.%s",domain);
-
-  FIXME("network related - move to dirmngr or drop the code");
-  srvcount=getsrv(srvname,&srvlist);
-
-  for(i=0;i<srvcount;i++)
-    {
-      hostlen+=strlen(srvlist[i].target)+1;
-      keyserver->host=xrealloc(keyserver->host,hostlen);
-
-      strcat(keyserver->host,srvlist[i].target);
-
-      if(srvlist[i].port!=389)
-	{
-	  char port[7];
-
-	  hostlen+=6; /* a colon, plus 5 digits (unsigned 16-bit value) */
-	  keyserver->host=xrealloc(keyserver->host,hostlen);
-
-	  snprintf(port,7,":%u",srvlist[i].port);
-	  strcat(keyserver->host,port);
-	}
-
-      strcat(keyserver->host," ");
-    }
-
-  free(srvlist);
-
-  /* If all else fails, do the PGP Universal trick of
-     ldap://keys.(domain) */
-
-  hostlen+=5+strlen(domain);
-  keyserver->host=xrealloc(keyserver->host,hostlen);
-  strcat(keyserver->host,"keys.");
-  strcat(keyserver->host,domain);
-
-  append_to_strlist(&list,name);
-
-  rc = gpg_error (GPG_ERR_NOT_IMPLEMENTED); /*FIXME*/
-       /* keyserver_work (ctrl, KS_GETNAME, list, NULL, */
-       /*                 0, fpr, fpr_len, keyserver); */
-
-  free_strlist(list);
-
-  free_keyserver_spec(keyserver);
-
-  return rc;
-#endif
-}

g10/main.h

@@ -327,6 +327,7 @@ gpg_error_t make_backsig (ctrl_t ctrl,
                           PKT_signature *sig, PKT_public_key *pk,
                           PKT_public_key *sub_pk, PKT_public_key *sub_psk,
                           u32 timestamp, const char *cache_nonce);
+void keygen_prepare_new_key_adsks (void);
 gpg_error_t generate_subkeypair (ctrl_t ctrl, kbnode_t keyblock,
                                  const char *algostr,
                                  const char *usagestr,