agent: Implement new protection mode openpgp-s2k3-ocb-aes.

* agent/protect.c (agent_protect): Add arg use_ocb.  Change all caller
to pass -1 for default.
* agent/protect-tool.c: New option --debug-use-ocb.
(oDebugUseOCB): New.
(opt_debug_use_ocb): New.
(main): Set option.
(read_and_protect): Implement option.

* agent/protect.c (OCB_MODE_SUPPORTED): New macro.
(PROT_DEFAULT_TO_OCB): New macro.
(do_encryption): Add args use_ocb, hashbegin, hashlen, timestamp_exp,
and timestamp_exp_len.  Implement OCB.
(agent_protect): Change to support OCB.
(do_decryption): Add new args is_ocb, aadhole_begin, and aadhole_len.
Implement OCB.
(merge_lists): Allow NULL for sha1hash.
(agent_unprotect): Change to support OCB.
(agent_private_key_type): Remove debug output.
--

Instead of using the old OpenPGP way of appending a hash of the
plaintext and encrypt that along with the plaintext, the new scheme
uses a proper authenticated encryption mode.  See keyformat.txt for a
description.  Libgcrypt 1.7 is required.

This mode is not yet enabled because there would be no way to return
to an older GnuPG version.  To test the new scheme use
gpg-protect-tool:

 ./gpg-protect-tool -av -P abc -p --debug-use-ocb <plain.key >prot.key
 ./gpg-protect-tool -av -P abc -u <prot.key

Any key from the private key storage should work.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 7 insertions, 1 deletions

diff --git a/agent/protect-tool.c b/agent/protect-tool.c
index 03dbda939..1871ac7af 100644
--- a/agent/protect-tool.c
+++ b/agent/protect-tool.c
@@ -69,6 +69,7 @@ enum cmd_and_opt_values
   oHomedir,
   oPrompt,
   oStatusMsg,
+  oDebugUseOCB,
 
   oAgentProgram
 };
@@ -96,6 +97,7 @@ static const char *opt_passphrase;
 static char *opt_prompt;
 static int opt_status_msg;
 static const char *opt_agent_program;
+static int opt_debug_use_ocb;
 
 static char *get_passphrase (int promptno);
 static void release_passphrase (char *pw);
@@ -132,6 +134,8 @@ static ARGPARSE_OPTS opts[] = {
 
   ARGPARSE_s_s (oAgentProgram, "agent-program", "@"),
 
+  ARGPARSE_s_n (oDebugUseOCB,  "debug-use-ocb", "@"), /* For hacking only.  */
+
   ARGPARSE_end ()
 };
 
@@ -333,7 +337,8 @@ read_and_protect (const char *fname)
     return;
 
   pw = get_passphrase (1);
-  rc = agent_protect (key, pw, &result, &resultlen, 0);
+  rc = agent_protect (key, pw, &result, &resultlen, 0,
+                      opt_debug_use_ocb? 1 : -1);
   release_passphrase (pw);
   xfree (key);
   if (rc)
@@ -598,6 +603,7 @@ main (int argc, char **argv )
         case oHaveCert: opt_have_cert = 1; break;
         case oPrompt: opt_prompt = pargs.r.ret_str; break;
         case oStatusMsg: opt_status_msg = 1; break;
+        case oDebugUseOCB: opt_debug_use_ocb = 1; break;
 
         default: pargs.err = ARGPARSE_PRINT_ERROR; break;
 	}