From 6cc4119ec03be61c78189a0bec99372035289b91 Mon Sep 17 00:00:00 2001
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Fri, 5 Jul 2019 15:16:08 +0900
Subject: [PATCH] gpg: Return the last error for pubkey decryption.

* g10/mainproc.c (proc_encrypted): Check ->result against -1.
When c->dek == NULL, put GPG_ERR_NO_SECKEY only when not set.
* g10/pubkey-enc.c (get_session_key): Set k->result by the result of
get_it.
When no secret key is available for some reasons, return the last
specific error, if any.

GnuPG-bug-id: 4561
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
---
 g10/mainproc.c   |  7 +++++--
 g10/pubkey-enc.c | 36 ++++++++++++++++++++----------------
 2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/g10/mainproc.c b/g10/mainproc.c
index d99ac4386..ba03de660 100644
--- a/g10/mainproc.c
+++ b/g10/mainproc.c
@@ -583,7 +583,7 @@ proc_encrypted (CTX c, PACKET *pkt)
           struct pubkey_enc_list *list;
 
           for (list = c->pkenc_list; list; list = list->next)
-            if (list->result == GPG_ERR_NO_SECKEY)
+            if (list->result != -1)
               {
                 char buf[20];
                 snprintf (buf, sizeof buf, "%08lX%08lX",
@@ -668,7 +668,10 @@ proc_encrypted (CTX c, PACKET *pkt)
         }
     }
   else if (!c->dek)
-    result = GPG_ERR_NO_SECKEY;
+    {
+      if (!result)
+        result = GPG_ERR_NO_SECKEY;
+    }
 
   /* Compute compliance with CO_DE_VS.  */
   if (!result && is_status_enabled ()
diff --git a/g10/pubkey-enc.c b/g10/pubkey-enc.c
index f61fa7abe..fb1b17143 100644
--- a/g10/pubkey-enc.c
+++ b/g10/pubkey-enc.c
@@ -75,25 +75,21 @@ gpg_error_t
 get_session_key (ctrl_t ctrl, struct pubkey_enc_list *list, DEK *dek)
 {
   PKT_public_key *sk = NULL;
-  int rc;
+  gpg_error_t err;
   void *enum_context = NULL;
   u32 keyid[2];
   int search_for_secret_keys = 1;
+  struct pubkey_enc_list *k;
 
   if (DBG_CLOCK)
     log_clock ("get_session_key enter");
 
   while (search_for_secret_keys)
     {
-      struct pubkey_enc_list *k;
-
       sk = xmalloc_clear (sizeof *sk);
-      rc = enum_secret_keys (ctrl, &enum_context, sk);
-      if (rc)
-        {
-          rc = GPG_ERR_NO_SECKEY;
-          break;
-        }
+      err = enum_secret_keys (ctrl, &enum_context, sk);
+      if (err)
+        break;
 
       if (!(sk->pubkey_usage & PUBKEY_USAGE_ENC))
         continue;
@@ -132,8 +128,6 @@ get_session_key (ctrl_t ctrl, struct pubkey_enc_list *list, DEK *dek)
           if (openpgp_pk_test_algo2 (k->pubkey_algo, PUBKEY_USAGE_ENC))
             continue;
 
-          k->result = GPG_ERR_NO_SECKEY;
-
           if (sk->pubkey_algo != k->pubkey_algo)
             continue;
 
@@ -154,16 +148,16 @@ get_session_key (ctrl_t ctrl, struct pubkey_enc_list *list, DEK *dek)
           else
             continue;
 
-          rc = get_it (ctrl, k, dek, sk, keyid);
-          if (!rc)
+          err = get_it (ctrl, k, dek, sk, keyid);
+          k->result = err;
+          if (!err)
             {
-              k->result = 0;
               if (!opt.quiet && !k->keyid[0] && !k->keyid[1])
                 log_info (_("okay, we are the anonymous recipient.\n"));
               search_for_secret_keys = 0;
               break;
             }
-          else if (gpg_err_code (rc) == GPG_ERR_FULLY_CANCELED)
+          else if (gpg_err_code (err) == GPG_ERR_FULLY_CANCELED)
             {
               search_for_secret_keys = 0;
               break; /* Don't try any more secret keys.  */
@@ -172,9 +166,19 @@ get_session_key (ctrl_t ctrl, struct pubkey_enc_list *list, DEK *dek)
     }
   enum_secret_keys (ctrl, &enum_context, NULL);  /* free context */
 
+  if (gpg_err_code (err) == GPG_ERR_EOF)
+    {
+      err = gpg_error (GPG_ERR_NO_SECKEY);
+
+      /* Return the last specific error, if any.  */
+      for (k = list; k; k = k->next)
+        if (k->result != -1)
+          err = k->result;
+    }
+
   if (DBG_CLOCK)
     log_clock ("get_session_key leave");
-  return rc;
+  return err;
 }