gpg: Avoid wrong decryption_failed for signed+OCB msg w/o pubkey.

* g10/decrypt-data.c (struct decode_filter_context_s): Add flag
checktag_failed.
(aead_checktag): Set flag.
(decrypt_data): Initially clear that flag and check the flag after the
decryption.
* g10/mainproc.c (proc_encrypted): Revert the log_get_errorcount based
check.
--

This fixes a bug where for an OCB encrypted and signed message with
the signing key missing during decryption the DECRYPTION_FAILED status
line was printed along with "WARNING: encrypted message has been
manipulated". This was because we use log_error to show that the
signature could not be verified due to the missing pubkey; the
original fix looked at the error counter and thus triggered the
decryption failed status.

Fixes-commit: 50e81ad38d2b5a5028fa6815da358c0496aa927e
GnuPG-bug-id: 7042

1 files changed, 2 insertions, 5 deletions

diff --git a/g10/mainproc.c b/g10/mainproc.c
index 2429e1006..039db9ccd 100644
--- a/g10/mainproc.c
+++ b/g10/mainproc.c
@@ -798,15 +798,12 @@ proc_encrypted (CTX c, PACKET *pkt)
         compliance_de_vs |= 2;
     }
 
-  /* Trigger the deferred error.  The second condition makes sure that a
-   * log_error printed in the cry_cipher_checktag never gets ignored.  */
+  /* Trigger the deferred error.  */
   if (!result && early_plaintext)
     result = gpg_error (GPG_ERR_BAD_DATA);
   else if (!result && opt.show_only_session_key)
     result = -1;
-  else if (!result && pkt->pkt.encrypted->aead_algo
-           && log_get_errorcount (0))
-    result = gpg_error (GPG_ERR_BAD_SIGNATURE);
+
 
   if (result == -1)
     ;