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6ab0fac575
* agent/agent.h (PRIVATE_KEY_OPENPGP_NONE): New. * agent/command.c (do_one_keyinfo): Implement it. * agent/findkey.c (agent_key_from_file): Ditto. (agent_key_info_from_file): Ditto. (agent_delete_key): Ditto. * agent/protect.c (agent_private_key_type): Add detection for openpgp "none" method. Signed-off-by: Werner Koch <wk@gnupg.org>
1324 lines
36 KiB
C
1324 lines
36 KiB
C
/* findkey.c - Locate the secret key
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* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007,
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* 2010, 2011 Free Software Foundation, Inc.
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* Copyright (C) 2014 Werner Koch
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include <assert.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <assert.h>
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#include <npth.h> /* (we use pth_sleep) */
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#include "agent.h"
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#include "i18n.h"
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#include "../common/ssh-utils.h"
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#ifndef O_BINARY
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#define O_BINARY 0
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#endif
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/* Helper to pass data to the check callback of the unprotect function. */
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struct try_unprotect_arg_s
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{
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ctrl_t ctrl;
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const unsigned char *protected_key;
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unsigned char *unprotected_key;
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int change_required; /* Set by the callback to indicate that the
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user should chnage the passphrase. */
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};
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/* Write an S-expression formatted key to our key storage. With FORCE
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passed as true an existing key with the given GRIP will get
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overwritten. */
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int
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agent_write_private_key (const unsigned char *grip,
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const void *buffer, size_t length, int force)
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{
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char *fname;
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estream_t fp;
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char hexgrip[40+4+1];
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bin2hex (grip, 20, hexgrip);
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strcpy (hexgrip+40, ".key");
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fname = make_filename (opt.homedir, GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL);
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/* FIXME: Write to a temp file first so that write failures during
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key updates won't lead to a key loss. */
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if (!force && !access (fname, F_OK))
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{
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log_error ("secret key file '%s' already exists\n", fname);
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xfree (fname);
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return gpg_error (GPG_ERR_EEXIST);
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}
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fp = es_fopen (fname, force? "wb,mode=-rw" : "wbx,mode=-rw");
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if (!fp)
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{
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gpg_error_t tmperr = gpg_error_from_syserror ();
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log_error ("can't create '%s': %s\n", fname, gpg_strerror (tmperr));
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xfree (fname);
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return tmperr;
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}
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if (es_fwrite (buffer, length, 1, fp) != 1)
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{
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gpg_error_t tmperr = gpg_error_from_syserror ();
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log_error ("error writing '%s': %s\n", fname, gpg_strerror (tmperr));
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es_fclose (fp);
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gnupg_remove (fname);
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xfree (fname);
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return tmperr;
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}
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if (es_fclose (fp))
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{
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gpg_error_t tmperr = gpg_error_from_syserror ();
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log_error ("error closing '%s': %s\n", fname, gpg_strerror (tmperr));
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gnupg_remove (fname);
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xfree (fname);
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return tmperr;
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}
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bump_key_eventcounter ();
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xfree (fname);
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return 0;
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}
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/* Callback function to try the unprotection from the passphrase query
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code. */
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static int
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try_unprotect_cb (struct pin_entry_info_s *pi)
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{
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struct try_unprotect_arg_s *arg = pi->check_cb_arg;
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size_t dummy;
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gpg_error_t err;
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gnupg_isotime_t now, protected_at, tmptime;
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char *desc = NULL;
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assert (!arg->unprotected_key);
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arg->change_required = 0;
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err = agent_unprotect (arg->ctrl, arg->protected_key, pi->pin, protected_at,
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&arg->unprotected_key, &dummy);
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if (err)
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return err;
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if (!opt.max_passphrase_days || arg->ctrl->in_passwd)
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return 0; /* No regular passphrase change required. */
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if (!*protected_at)
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{
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/* No protection date known - must force passphrase change. */
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desc = xtrystrdup (_("Note: This passphrase has never been changed.%0A"
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"Please change it now."));
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if (!desc)
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return gpg_error_from_syserror ();
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}
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else
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{
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gnupg_get_isotime (now);
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gnupg_copy_time (tmptime, protected_at);
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err = add_days_to_isotime (tmptime, opt.max_passphrase_days);
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if (err)
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return err;
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if (strcmp (now, tmptime) > 0 )
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{
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/* Passphrase "expired". */
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desc = xtryasprintf
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(_("This passphrase has not been changed%%0A"
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"since %.4s-%.2s-%.2s. Please change it now."),
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protected_at, protected_at+4, protected_at+6);
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if (!desc)
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return gpg_error_from_syserror ();
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}
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}
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if (desc)
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{
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/* Change required. */
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if (opt.enforce_passphrase_constraints)
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{
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err = agent_get_confirmation (arg->ctrl, desc,
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_("Change passphrase"), NULL, 0);
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if (!err)
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arg->change_required = 1;
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}
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else
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{
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err = agent_get_confirmation (arg->ctrl, desc,
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_("Change passphrase"),
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_("I'll change it later"), 0);
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if (!err)
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arg->change_required = 1;
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else if (gpg_err_code (err) == GPG_ERR_CANCELED
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|| gpg_err_code (err) == GPG_ERR_FULLY_CANCELED)
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err = 0;
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}
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xfree (desc);
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}
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return 0;
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}
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/* Modify a Key description, replacing certain special format
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characters. List of currently supported replacements:
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%% - Replaced by a single %
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%c - Replaced by the content of COMMENT.
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%C - Same as %c but put into parentheses.
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%F - Replaced by an ssh style fingerprint computed from KEY.
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The functions returns 0 on success or an error code. On success a
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newly allocated string is stored at the address of RESULT.
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*/
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static gpg_error_t
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modify_description (const char *in, const char *comment, const gcry_sexp_t key,
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char **result)
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{
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size_t comment_length;
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size_t in_len;
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size_t out_len;
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char *out;
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size_t i;
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int special, pass;
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char *ssh_fpr = NULL;
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comment_length = strlen (comment);
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in_len = strlen (in);
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/* First pass calculates the length, second pass does the actual
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copying. */
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out = NULL;
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out_len = 0;
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for (pass=0; pass < 2; pass++)
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{
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special = 0;
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for (i = 0; i < in_len; i++)
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{
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if (special)
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{
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special = 0;
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switch (in[i])
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{
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case '%':
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if (out)
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*out++ = '%';
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else
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out_len++;
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break;
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case 'c': /* Comment. */
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if (out)
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{
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memcpy (out, comment, comment_length);
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out += comment_length;
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}
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else
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out_len += comment_length;
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break;
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case 'C': /* Comment. */
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if (!comment_length)
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;
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else if (out)
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{
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*out++ = '(';
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memcpy (out, comment, comment_length);
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out += comment_length;
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*out++ = ')';
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}
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else
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out_len += comment_length + 2;
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break;
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case 'F': /* SSH style fingerprint. */
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if (!ssh_fpr && key)
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ssh_get_fingerprint_string (key, &ssh_fpr);
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if (ssh_fpr)
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{
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if (out)
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out = stpcpy (out, ssh_fpr);
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else
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out_len += strlen (ssh_fpr);
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}
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break;
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default: /* Invalid special sequences are kept as they are. */
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if (out)
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{
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*out++ = '%';
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*out++ = in[i];
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}
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else
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out_len+=2;
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break;
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}
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}
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else if (in[i] == '%')
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special = 1;
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else
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{
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if (out)
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*out++ = in[i];
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else
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out_len++;
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}
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}
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if (!pass)
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{
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*result = out = xtrymalloc (out_len + 1);
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if (!out)
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{
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xfree (ssh_fpr);
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return gpg_error_from_syserror ();
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}
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}
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}
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*out = 0;
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assert (*result + out_len == out);
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xfree (ssh_fpr);
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return 0;
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}
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/* Unprotect the canconical encoded S-expression key in KEYBUF. GRIP
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should be the hex encoded keygrip of that key to be used with the
|
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caching mechanism. DESC_TEXT may be set to override the default
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description used for the pinentry. If LOOKUP_TTL is given this
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function is used to lookup the default ttl. If R_PASSPHRASE is not
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NULL, the function succeeded and the key was protected the used
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passphrase (entered or from the cache) is stored there; if not NULL
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will be stored. The caller needs to free the returned
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passphrase. */
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static int
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unprotect (ctrl_t ctrl, const char *cache_nonce, const char *desc_text,
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unsigned char **keybuf, const unsigned char *grip,
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cache_mode_t cache_mode, lookup_ttl_t lookup_ttl,
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char **r_passphrase)
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{
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struct pin_entry_info_s *pi;
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struct try_unprotect_arg_s arg;
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int rc;
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unsigned char *result;
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size_t resultlen;
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char hexgrip[40+1];
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if (r_passphrase)
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*r_passphrase = NULL;
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bin2hex (grip, 20, hexgrip);
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/* Initially try to get it using a cache nonce. */
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if (cache_nonce)
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{
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char *pw;
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pw = agent_get_cache (cache_nonce, CACHE_MODE_NONCE);
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if (pw)
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{
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rc = agent_unprotect (ctrl, *keybuf, pw, NULL, &result, &resultlen);
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if (!rc)
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{
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if (r_passphrase)
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*r_passphrase = pw;
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else
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xfree (pw);
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xfree (*keybuf);
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*keybuf = result;
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return 0;
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}
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xfree (pw);
|
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}
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}
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/* First try to get it from the cache - if there is none or we can't
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unprotect it, we fall back to ask the user */
|
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if (cache_mode != CACHE_MODE_IGNORE)
|
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{
|
||
char *pw;
|
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|
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retry:
|
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pw = agent_get_cache (hexgrip, cache_mode);
|
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if (pw)
|
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{
|
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rc = agent_unprotect (ctrl, *keybuf, pw, NULL, &result, &resultlen);
|
||
if (!rc)
|
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{
|
||
if (cache_mode == CACHE_MODE_NORMAL)
|
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agent_store_cache_hit (hexgrip);
|
||
if (r_passphrase)
|
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*r_passphrase = pw;
|
||
else
|
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xfree (pw);
|
||
xfree (*keybuf);
|
||
*keybuf = result;
|
||
return 0;
|
||
}
|
||
xfree (pw);
|
||
rc = 0;
|
||
}
|
||
else if (cache_mode == CACHE_MODE_NORMAL)
|
||
{
|
||
/* The standard use of GPG keys is to have a signing and an
|
||
encryption subkey. Commonly both use the same
|
||
passphrase. We try to help the user to enter the
|
||
passphrase only once by silently trying the last
|
||
correctly entered passphrase. Checking one additional
|
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passphrase should be acceptable; despite the S2K
|
||
introduced delays. The assumed workflow is:
|
||
|
||
1. Read encrypted message in a MUA and thus enter a
|
||
passphrase for the encryption subkey.
|
||
|
||
2. Reply to that mail with an encrypted and signed
|
||
mail, thus entering the passphrase for the signing
|
||
subkey.
|
||
|
||
We can often avoid the passphrase entry in the second
|
||
step. We do this only in normal mode, so not to
|
||
interfere with unrelated cache entries. */
|
||
pw = agent_get_cache (NULL, cache_mode);
|
||
if (pw)
|
||
{
|
||
rc = agent_unprotect (ctrl, *keybuf, pw, NULL,
|
||
&result, &resultlen);
|
||
if (!rc)
|
||
{
|
||
if (r_passphrase)
|
||
*r_passphrase = pw;
|
||
else
|
||
xfree (pw);
|
||
xfree (*keybuf);
|
||
*keybuf = result;
|
||
return 0;
|
||
}
|
||
xfree (pw);
|
||
rc = 0;
|
||
}
|
||
}
|
||
|
||
/* If the pinentry is currently in use, we wait up to 60 seconds
|
||
for it to close and check the cache again. This solves a common
|
||
situation where several requests for unprotecting a key have
|
||
been made but the user is still entering the passphrase for
|
||
the first request. Because all requests to agent_askpin are
|
||
serialized they would then pop up one after the other to
|
||
request the passphrase - despite that the user has already
|
||
entered it and is then available in the cache. This
|
||
implementation is not race free but in the worst case the
|
||
user has to enter the passphrase only once more. */
|
||
if (pinentry_active_p (ctrl, 0))
|
||
{
|
||
/* Active - wait */
|
||
if (!pinentry_active_p (ctrl, 60))
|
||
{
|
||
/* We need to give the other thread a chance to actually put
|
||
it into the cache. */
|
||
npth_sleep (1);
|
||
goto retry;
|
||
}
|
||
/* Timeout - better call pinentry now the plain way. */
|
||
}
|
||
}
|
||
|
||
pi = gcry_calloc_secure (1, sizeof (*pi) + 100);
|
||
if (!pi)
|
||
return gpg_error_from_syserror ();
|
||
pi->max_length = 100;
|
||
pi->min_digits = 0; /* we want a real passphrase */
|
||
pi->max_digits = 16;
|
||
pi->max_tries = 3;
|
||
pi->check_cb = try_unprotect_cb;
|
||
arg.ctrl = ctrl;
|
||
arg.protected_key = *keybuf;
|
||
arg.unprotected_key = NULL;
|
||
arg.change_required = 0;
|
||
pi->check_cb_arg = &arg;
|
||
|
||
rc = agent_askpin (ctrl, desc_text, NULL, NULL, pi);
|
||
if (!rc)
|
||
{
|
||
assert (arg.unprotected_key);
|
||
if (arg.change_required)
|
||
{
|
||
size_t canlen, erroff;
|
||
gcry_sexp_t s_skey;
|
||
|
||
assert (arg.unprotected_key);
|
||
canlen = gcry_sexp_canon_len (arg.unprotected_key, 0, NULL, NULL);
|
||
rc = gcry_sexp_sscan (&s_skey, &erroff,
|
||
(char*)arg.unprotected_key, canlen);
|
||
if (rc)
|
||
{
|
||
log_error ("failed to build S-Exp (off=%u): %s\n",
|
||
(unsigned int)erroff, gpg_strerror (rc));
|
||
wipememory (arg.unprotected_key, canlen);
|
||
xfree (arg.unprotected_key);
|
||
xfree (pi);
|
||
return rc;
|
||
}
|
||
rc = agent_protect_and_store (ctrl, s_skey, NULL);
|
||
gcry_sexp_release (s_skey);
|
||
if (rc)
|
||
{
|
||
log_error ("changing the passphrase failed: %s\n",
|
||
gpg_strerror (rc));
|
||
wipememory (arg.unprotected_key, canlen);
|
||
xfree (arg.unprotected_key);
|
||
xfree (pi);
|
||
return rc;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
agent_put_cache (hexgrip, cache_mode, pi->pin,
|
||
lookup_ttl? lookup_ttl (hexgrip) : 0);
|
||
agent_store_cache_hit (hexgrip);
|
||
if (r_passphrase && *pi->pin)
|
||
*r_passphrase = xtrystrdup (pi->pin);
|
||
}
|
||
xfree (*keybuf);
|
||
*keybuf = arg.unprotected_key;
|
||
}
|
||
xfree (pi);
|
||
return rc;
|
||
}
|
||
|
||
|
||
/* Read the key identified by GRIP from the private key directory and
|
||
return it as an gcrypt S-expression object in RESULT. On failure
|
||
returns an error code and stores NULL at RESULT. */
|
||
static gpg_error_t
|
||
read_key_file (const unsigned char *grip, gcry_sexp_t *result)
|
||
{
|
||
int rc;
|
||
char *fname;
|
||
estream_t fp;
|
||
struct stat st;
|
||
unsigned char *buf;
|
||
size_t buflen, erroff;
|
||
gcry_sexp_t s_skey;
|
||
char hexgrip[40+4+1];
|
||
|
||
*result = NULL;
|
||
|
||
bin2hex (grip, 20, hexgrip);
|
||
strcpy (hexgrip+40, ".key");
|
||
|
||
fname = make_filename (opt.homedir, GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL);
|
||
fp = es_fopen (fname, "rb");
|
||
if (!fp)
|
||
{
|
||
rc = gpg_error_from_syserror ();
|
||
if (gpg_err_code (rc) != GPG_ERR_ENOENT)
|
||
log_error ("can't open '%s': %s\n", fname, strerror (errno));
|
||
xfree (fname);
|
||
return rc;
|
||
}
|
||
|
||
if (fstat (es_fileno (fp), &st))
|
||
{
|
||
rc = gpg_error_from_syserror ();
|
||
log_error ("can't stat '%s': %s\n", fname, strerror (errno));
|
||
xfree (fname);
|
||
es_fclose (fp);
|
||
return rc;
|
||
}
|
||
|
||
buflen = st.st_size;
|
||
buf = xtrymalloc (buflen+1);
|
||
if (!buf)
|
||
{
|
||
rc = gpg_error_from_syserror ();
|
||
log_error ("error allocating %zu bytes for '%s': %s\n",
|
||
buflen, fname, strerror (errno));
|
||
xfree (fname);
|
||
es_fclose (fp);
|
||
xfree (buf);
|
||
return rc;
|
||
|
||
}
|
||
|
||
if (es_fread (buf, buflen, 1, fp) != 1)
|
||
{
|
||
rc = gpg_error_from_syserror ();
|
||
log_error ("error reading %zu bytes from '%s': %s\n",
|
||
buflen, fname, strerror (errno));
|
||
xfree (fname);
|
||
es_fclose (fp);
|
||
xfree (buf);
|
||
return rc;
|
||
}
|
||
|
||
/* Convert the file into a gcrypt S-expression object. */
|
||
rc = gcry_sexp_sscan (&s_skey, &erroff, (char*)buf, buflen);
|
||
xfree (fname);
|
||
es_fclose (fp);
|
||
xfree (buf);
|
||
if (rc)
|
||
{
|
||
log_error ("failed to build S-Exp (off=%u): %s\n",
|
||
(unsigned int)erroff, gpg_strerror (rc));
|
||
return rc;
|
||
}
|
||
*result = s_skey;
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Remove the key identified by GRIP from the private key directory. */
|
||
static gpg_error_t
|
||
remove_key_file (const unsigned char *grip)
|
||
{
|
||
gpg_error_t err = 0;
|
||
char *fname;
|
||
char hexgrip[40+4+1];
|
||
|
||
bin2hex (grip, 20, hexgrip);
|
||
strcpy (hexgrip+40, ".key");
|
||
fname = make_filename (opt.homedir, GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL);
|
||
if (gnupg_remove (fname))
|
||
err = gpg_error_from_syserror ();
|
||
xfree (fname);
|
||
return err;
|
||
}
|
||
|
||
|
||
/* Return the secret key as an S-Exp in RESULT after locating it using
|
||
the GRIP. If the operation shall be diverted to a token, an
|
||
allocated S-expression with the shadow_info part from the file is
|
||
stored at SHADOW_INFO; if not NULL will be stored at SHADOW_INFO.
|
||
CACHE_MODE defines now the cache shall be used. DESC_TEXT may be
|
||
set to present a custom description for the pinentry. LOOKUP_TTL
|
||
is an optional function to convey a TTL to the cache manager; we do
|
||
not simply pass the TTL value because the value is only needed if
|
||
an unprotect action was needed and looking up the TTL may have some
|
||
overhead (e.g. scanning the sshcontrol file). If a CACHE_NONCE is
|
||
given that cache item is first tried to get a passphrase. If
|
||
R_PASSPHRASE is not NULL, the function succeeded and the key was
|
||
protected the used passphrase (entered or from the cache) is stored
|
||
there; if not NULL will be stored. The caller needs to free the
|
||
returned passphrase. */
|
||
gpg_error_t
|
||
agent_key_from_file (ctrl_t ctrl, const char *cache_nonce,
|
||
const char *desc_text,
|
||
const unsigned char *grip, unsigned char **shadow_info,
|
||
cache_mode_t cache_mode, lookup_ttl_t lookup_ttl,
|
||
gcry_sexp_t *result, char **r_passphrase)
|
||
{
|
||
int rc;
|
||
unsigned char *buf;
|
||
size_t len, buflen, erroff;
|
||
gcry_sexp_t s_skey;
|
||
|
||
*result = NULL;
|
||
if (shadow_info)
|
||
*shadow_info = NULL;
|
||
if (r_passphrase)
|
||
*r_passphrase = NULL;
|
||
|
||
rc = read_key_file (grip, &s_skey);
|
||
if (rc)
|
||
{
|
||
if (gpg_err_code (rc) == GPG_ERR_ENOENT)
|
||
rc = gpg_error (GPG_ERR_NO_SECKEY);
|
||
return rc;
|
||
}
|
||
|
||
/* For use with the protection functions we also need the key as an
|
||
canonical encoded S-expression in a buffer. Create this buffer
|
||
now. */
|
||
rc = make_canon_sexp (s_skey, &buf, &len);
|
||
if (rc)
|
||
return rc;
|
||
|
||
switch (agent_private_key_type (buf))
|
||
{
|
||
case PRIVATE_KEY_CLEAR:
|
||
break; /* no unprotection needed */
|
||
case PRIVATE_KEY_OPENPGP_NONE:
|
||
{
|
||
unsigned char *buf_new;
|
||
size_t buf_newlen;
|
||
|
||
rc = agent_unprotect (ctrl, buf, "", NULL, &buf_new, &buf_newlen);
|
||
if (rc)
|
||
log_error ("failed to convert unprotected openpgp key: %s\n",
|
||
gpg_strerror (rc));
|
||
else
|
||
{
|
||
xfree (buf);
|
||
buf = buf_new;
|
||
}
|
||
}
|
||
break;
|
||
case PRIVATE_KEY_PROTECTED:
|
||
{
|
||
char *desc_text_final;
|
||
char *comment = NULL;
|
||
|
||
/* Note, that we will take the comment as a C string for
|
||
display purposes; i.e. all stuff beyond a Nul character is
|
||
ignored. */
|
||
{
|
||
gcry_sexp_t comment_sexp;
|
||
|
||
comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
|
||
if (comment_sexp)
|
||
comment = gcry_sexp_nth_string (comment_sexp, 1);
|
||
gcry_sexp_release (comment_sexp);
|
||
}
|
||
|
||
desc_text_final = NULL;
|
||
if (desc_text)
|
||
rc = modify_description (desc_text, comment? comment:"", s_skey,
|
||
&desc_text_final);
|
||
gcry_free (comment);
|
||
|
||
if (!rc)
|
||
{
|
||
rc = unprotect (ctrl, cache_nonce, desc_text_final, &buf, grip,
|
||
cache_mode, lookup_ttl, r_passphrase);
|
||
if (rc)
|
||
log_error ("failed to unprotect the secret key: %s\n",
|
||
gpg_strerror (rc));
|
||
}
|
||
|
||
xfree (desc_text_final);
|
||
}
|
||
break;
|
||
case PRIVATE_KEY_SHADOWED:
|
||
if (shadow_info)
|
||
{
|
||
const unsigned char *s;
|
||
size_t n;
|
||
|
||
rc = agent_get_shadow_info (buf, &s);
|
||
if (!rc)
|
||
{
|
||
n = gcry_sexp_canon_len (s, 0, NULL,NULL);
|
||
assert (n);
|
||
*shadow_info = xtrymalloc (n);
|
||
if (!*shadow_info)
|
||
rc = out_of_core ();
|
||
else
|
||
{
|
||
memcpy (*shadow_info, s, n);
|
||
rc = 0;
|
||
}
|
||
}
|
||
if (rc)
|
||
log_error ("get_shadow_info failed: %s\n", gpg_strerror (rc));
|
||
}
|
||
else
|
||
rc = gpg_error (GPG_ERR_UNUSABLE_SECKEY);
|
||
break;
|
||
default:
|
||
log_error ("invalid private key format\n");
|
||
rc = gpg_error (GPG_ERR_BAD_SECKEY);
|
||
break;
|
||
}
|
||
gcry_sexp_release (s_skey);
|
||
s_skey = NULL;
|
||
if (rc)
|
||
{
|
||
xfree (buf);
|
||
if (r_passphrase)
|
||
{
|
||
xfree (*r_passphrase);
|
||
*r_passphrase = NULL;
|
||
}
|
||
return rc;
|
||
}
|
||
|
||
buflen = gcry_sexp_canon_len (buf, 0, NULL, NULL);
|
||
rc = gcry_sexp_sscan (&s_skey, &erroff, (char*)buf, buflen);
|
||
wipememory (buf, buflen);
|
||
xfree (buf);
|
||
if (rc)
|
||
{
|
||
log_error ("failed to build S-Exp (off=%u): %s\n",
|
||
(unsigned int)erroff, gpg_strerror (rc));
|
||
if (r_passphrase)
|
||
{
|
||
xfree (*r_passphrase);
|
||
*r_passphrase = NULL;
|
||
}
|
||
return rc;
|
||
}
|
||
|
||
*result = s_skey;
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Return the string name from the S-expression S_KEY as well as a
|
||
string describing the names of the parameters. ALGONAMESIZE and
|
||
ELEMSSIZE give the allocated size of the provided buffers. The
|
||
buffers may be NULL if not required. If R_LIST is not NULL the top
|
||
level list will be stored there; the caller needs to release it in
|
||
this case. */
|
||
static gpg_error_t
|
||
key_parms_from_sexp (gcry_sexp_t s_key, gcry_sexp_t *r_list,
|
||
char *r_algoname, size_t algonamesize,
|
||
char *r_elems, size_t elemssize)
|
||
{
|
||
gcry_sexp_t list, l2;
|
||
const char *name, *algoname, *elems;
|
||
size_t n;
|
||
|
||
if (r_list)
|
||
*r_list = NULL;
|
||
|
||
list = gcry_sexp_find_token (s_key, "shadowed-private-key", 0 );
|
||
if (!list)
|
||
list = gcry_sexp_find_token (s_key, "protected-private-key", 0 );
|
||
if (!list)
|
||
list = gcry_sexp_find_token (s_key, "private-key", 0 );
|
||
if (!list)
|
||
{
|
||
log_error ("invalid private key format\n");
|
||
return gpg_error (GPG_ERR_BAD_SECKEY);
|
||
}
|
||
|
||
l2 = gcry_sexp_cadr (list);
|
||
gcry_sexp_release (list);
|
||
list = l2;
|
||
name = gcry_sexp_nth_data (list, 0, &n);
|
||
if (n==3 && !memcmp (name, "rsa", 3))
|
||
{
|
||
algoname = "rsa";
|
||
elems = "ne";
|
||
}
|
||
else if (n==3 && !memcmp (name, "dsa", 3))
|
||
{
|
||
algoname = "dsa";
|
||
elems = "pqgy";
|
||
}
|
||
else if (n==3 && !memcmp (name, "ecc", 3))
|
||
{
|
||
algoname = "ecc";
|
||
elems = "pabgnq";
|
||
}
|
||
else if (n==5 && !memcmp (name, "ecdsa", 5))
|
||
{
|
||
algoname = "ecdsa";
|
||
elems = "pabgnq";
|
||
}
|
||
else if (n==4 && !memcmp (name, "ecdh", 4))
|
||
{
|
||
algoname = "ecdh";
|
||
elems = "pabgnq";
|
||
}
|
||
else if (n==3 && !memcmp (name, "elg", 3))
|
||
{
|
||
algoname = "elg";
|
||
elems = "pgy";
|
||
}
|
||
else
|
||
{
|
||
log_error ("unknown private key algorithm\n");
|
||
gcry_sexp_release (list);
|
||
return gpg_error (GPG_ERR_BAD_SECKEY);
|
||
}
|
||
|
||
if (r_algoname)
|
||
{
|
||
if (strlen (algoname) >= algonamesize)
|
||
return gpg_error (GPG_ERR_BUFFER_TOO_SHORT);
|
||
strcpy (r_algoname, algoname);
|
||
}
|
||
if (r_elems)
|
||
{
|
||
if (strlen (elems) >= elemssize)
|
||
return gpg_error (GPG_ERR_BUFFER_TOO_SHORT);
|
||
strcpy (r_elems, elems);
|
||
}
|
||
|
||
if (r_list)
|
||
*r_list = list;
|
||
else
|
||
gcry_sexp_release (list);
|
||
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Return true if KEYPARMS holds an EdDSA key. */
|
||
static int
|
||
is_eddsa (gcry_sexp_t keyparms)
|
||
{
|
||
int result = 0;
|
||
gcry_sexp_t list;
|
||
const char *s;
|
||
size_t n;
|
||
int i;
|
||
|
||
list = gcry_sexp_find_token (keyparms, "flags", 0);
|
||
for (i = list ? gcry_sexp_length (list)-1 : 0; i > 0; i--)
|
||
{
|
||
s = gcry_sexp_nth_data (list, i, &n);
|
||
if (!s)
|
||
continue; /* Not a data element. */
|
||
|
||
if (n == 5 && !memcmp (s, "eddsa", 5))
|
||
{
|
||
result = 1;
|
||
break;
|
||
}
|
||
}
|
||
gcry_sexp_release (list);
|
||
return result;
|
||
}
|
||
|
||
|
||
/* Return the public key algorithm number if S_KEY is a DSA style key.
|
||
If it is not a DSA style key, return 0. */
|
||
int
|
||
agent_is_dsa_key (gcry_sexp_t s_key)
|
||
{
|
||
int result;
|
||
gcry_sexp_t list;
|
||
char algoname[6];
|
||
|
||
if (!s_key)
|
||
return 0;
|
||
|
||
if (key_parms_from_sexp (s_key, &list, algoname, sizeof algoname, NULL, 0))
|
||
return 0; /* Error - assume it is not an DSA key. */
|
||
|
||
if (!strcmp (algoname, "dsa"))
|
||
result = GCRY_PK_DSA;
|
||
else if (!strcmp (algoname, "ecc"))
|
||
{
|
||
if (is_eddsa (list))
|
||
result = 0;
|
||
else
|
||
result = GCRY_PK_ECDSA;
|
||
}
|
||
else if (!strcmp (algoname, "ecdsa"))
|
||
result = GCRY_PK_ECDSA;
|
||
else
|
||
result = 0;
|
||
|
||
gcry_sexp_release (list);
|
||
return result;
|
||
}
|
||
|
||
|
||
/* Return true if S_KEY is an EdDSA key as used with curve Ed25519. */
|
||
int
|
||
agent_is_eddsa_key (gcry_sexp_t s_key)
|
||
{
|
||
int result;
|
||
gcry_sexp_t list;
|
||
char algoname[6];
|
||
|
||
if (!s_key)
|
||
return 0;
|
||
|
||
if (key_parms_from_sexp (s_key, &list, algoname, sizeof algoname, NULL, 0))
|
||
return 0; /* Error - assume it is not an EdDSA key. */
|
||
|
||
if (!strcmp (algoname, "ecc") && is_eddsa (list))
|
||
result = 1;
|
||
else if (!strcmp (algoname, "eddsa")) /* backward compatibility. */
|
||
result = 1;
|
||
else
|
||
result = 0;
|
||
|
||
gcry_sexp_release (list);
|
||
return result;
|
||
}
|
||
|
||
|
||
/* Return the key for the keygrip GRIP. The result is stored at
|
||
RESULT. This function extracts the key from the private key
|
||
database and returns it as an S-expression object as it is. On
|
||
failure an error code is returned and NULL stored at RESULT. */
|
||
gpg_error_t
|
||
agent_raw_key_from_file (ctrl_t ctrl, const unsigned char *grip,
|
||
gcry_sexp_t *result)
|
||
{
|
||
gpg_error_t err;
|
||
gcry_sexp_t s_skey;
|
||
|
||
(void)ctrl;
|
||
|
||
*result = NULL;
|
||
|
||
err = read_key_file (grip, &s_skey);
|
||
if (!err)
|
||
*result = s_skey;
|
||
return err;
|
||
}
|
||
|
||
|
||
/* Return the public key for the keygrip GRIP. The result is stored
|
||
at RESULT. This function extracts the public key from the private
|
||
key database. On failure an error code is returned and NULL stored
|
||
at RESULT. */
|
||
gpg_error_t
|
||
agent_public_key_from_file (ctrl_t ctrl,
|
||
const unsigned char *grip,
|
||
gcry_sexp_t *result)
|
||
{
|
||
gpg_error_t err;
|
||
int i, idx;
|
||
gcry_sexp_t s_skey;
|
||
const char *algoname, *elems;
|
||
int npkey;
|
||
gcry_mpi_t array[10];
|
||
gcry_sexp_t curve = NULL;
|
||
gcry_sexp_t flags = NULL;
|
||
gcry_sexp_t uri_sexp, comment_sexp;
|
||
const char *uri, *comment;
|
||
size_t uri_length, comment_length;
|
||
char *format, *p;
|
||
void *args[2+7+2+2+1]; /* Size is 2 + max. # of elements + 2 for uri + 2
|
||
for comment + end-of-list. */
|
||
int argidx;
|
||
gcry_sexp_t list = NULL;
|
||
const char *s;
|
||
|
||
(void)ctrl;
|
||
|
||
*result = NULL;
|
||
|
||
err = read_key_file (grip, &s_skey);
|
||
if (err)
|
||
return err;
|
||
|
||
for (i=0; i < DIM (array); i++)
|
||
array[i] = NULL;
|
||
|
||
err = extract_private_key (s_skey, 0, &algoname, &npkey, NULL, &elems,
|
||
array, DIM (array), &curve, &flags);
|
||
if (err)
|
||
{
|
||
gcry_sexp_release (s_skey);
|
||
return err;
|
||
}
|
||
|
||
uri = NULL;
|
||
uri_length = 0;
|
||
uri_sexp = gcry_sexp_find_token (s_skey, "uri", 0);
|
||
if (uri_sexp)
|
||
uri = gcry_sexp_nth_data (uri_sexp, 1, &uri_length);
|
||
|
||
comment = NULL;
|
||
comment_length = 0;
|
||
comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
|
||
if (comment_sexp)
|
||
comment = gcry_sexp_nth_data (comment_sexp, 1, &comment_length);
|
||
|
||
gcry_sexp_release (s_skey);
|
||
s_skey = NULL;
|
||
|
||
|
||
/* FIXME: The following thing is pretty ugly code; we should
|
||
investigate how to make it cleaner. Probably code to handle
|
||
canonical S-expressions in a memory buffer is better suited for
|
||
such a task. After all that is what we do in protect.c. Neeed
|
||
to find common patterns and write a straightformward API to use
|
||
them. */
|
||
assert (sizeof (size_t) <= sizeof (void*));
|
||
|
||
format = xtrymalloc (15+4+7*npkey+10+15+1+1);
|
||
if (!format)
|
||
{
|
||
err = gpg_error_from_syserror ();
|
||
for (i=0; array[i]; i++)
|
||
gcry_mpi_release (array[i]);
|
||
gcry_sexp_release (curve);
|
||
gcry_sexp_release (flags);
|
||
gcry_sexp_release (uri_sexp);
|
||
gcry_sexp_release (comment_sexp);
|
||
return err;
|
||
}
|
||
|
||
argidx = 0;
|
||
p = stpcpy (stpcpy (format, "(public-key("), algoname);
|
||
p = stpcpy (p, "%S%S"); /* curve name and flags. */
|
||
args[argidx++] = &curve;
|
||
args[argidx++] = &flags;
|
||
for (idx=0, s=elems; idx < npkey; idx++)
|
||
{
|
||
*p++ = '(';
|
||
*p++ = *s++;
|
||
p = stpcpy (p, " %m)");
|
||
assert (argidx < DIM (args));
|
||
args[argidx++] = &array[idx];
|
||
}
|
||
*p++ = ')';
|
||
if (uri)
|
||
{
|
||
p = stpcpy (p, "(uri %b)");
|
||
assert (argidx+1 < DIM (args));
|
||
args[argidx++] = (void *)&uri_length;
|
||
args[argidx++] = (void *)&uri;
|
||
}
|
||
if (comment)
|
||
{
|
||
p = stpcpy (p, "(comment %b)");
|
||
assert (argidx+1 < DIM (args));
|
||
args[argidx++] = (void *)&comment_length;
|
||
args[argidx++] = (void*)&comment;
|
||
}
|
||
*p++ = ')';
|
||
*p = 0;
|
||
assert (argidx < DIM (args));
|
||
args[argidx] = NULL;
|
||
|
||
err = gcry_sexp_build_array (&list, NULL, format, args);
|
||
xfree (format);
|
||
for (i=0; array[i]; i++)
|
||
gcry_mpi_release (array[i]);
|
||
gcry_sexp_release (curve);
|
||
gcry_sexp_release (flags);
|
||
gcry_sexp_release (uri_sexp);
|
||
gcry_sexp_release (comment_sexp);
|
||
|
||
if (!err)
|
||
*result = list;
|
||
return err;
|
||
}
|
||
|
||
|
||
|
||
/* Check whether the the secret key identified by GRIP is available.
|
||
Returns 0 is the key is available. */
|
||
int
|
||
agent_key_available (const unsigned char *grip)
|
||
{
|
||
int result;
|
||
char *fname;
|
||
char hexgrip[40+4+1];
|
||
|
||
bin2hex (grip, 20, hexgrip);
|
||
strcpy (hexgrip+40, ".key");
|
||
|
||
fname = make_filename (opt.homedir, GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL);
|
||
result = !access (fname, R_OK)? 0 : -1;
|
||
xfree (fname);
|
||
return result;
|
||
}
|
||
|
||
|
||
|
||
/* Return the information about the secret key specified by the binary
|
||
keygrip GRIP. If the key is a shadowed one the shadow information
|
||
will be stored at the address R_SHADOW_INFO as an allocated
|
||
S-expression. */
|
||
gpg_error_t
|
||
agent_key_info_from_file (ctrl_t ctrl, const unsigned char *grip,
|
||
int *r_keytype, unsigned char **r_shadow_info)
|
||
{
|
||
gpg_error_t err;
|
||
unsigned char *buf;
|
||
size_t len;
|
||
int keytype;
|
||
|
||
(void)ctrl;
|
||
|
||
if (r_keytype)
|
||
*r_keytype = PRIVATE_KEY_UNKNOWN;
|
||
if (r_shadow_info)
|
||
*r_shadow_info = NULL;
|
||
|
||
{
|
||
gcry_sexp_t sexp;
|
||
|
||
err = read_key_file (grip, &sexp);
|
||
if (err)
|
||
{
|
||
if (gpg_err_code (err) == GPG_ERR_ENOENT)
|
||
return gpg_error (GPG_ERR_NOT_FOUND);
|
||
else
|
||
return err;
|
||
}
|
||
err = make_canon_sexp (sexp, &buf, &len);
|
||
gcry_sexp_release (sexp);
|
||
if (err)
|
||
return err;
|
||
}
|
||
|
||
keytype = agent_private_key_type (buf);
|
||
switch (keytype)
|
||
{
|
||
case PRIVATE_KEY_CLEAR:
|
||
case PRIVATE_KEY_OPENPGP_NONE:
|
||
break;
|
||
case PRIVATE_KEY_PROTECTED:
|
||
/* If we ever require it we could retrieve the comment fields
|
||
from such a key. */
|
||
break;
|
||
case PRIVATE_KEY_SHADOWED:
|
||
if (r_shadow_info)
|
||
{
|
||
const unsigned char *s;
|
||
size_t n;
|
||
|
||
err = agent_get_shadow_info (buf, &s);
|
||
if (!err)
|
||
{
|
||
n = gcry_sexp_canon_len (s, 0, NULL, NULL);
|
||
assert (n);
|
||
*r_shadow_info = xtrymalloc (n);
|
||
if (!*r_shadow_info)
|
||
err = gpg_error_from_syserror ();
|
||
else
|
||
memcpy (*r_shadow_info, s, n);
|
||
}
|
||
}
|
||
break;
|
||
default:
|
||
err = gpg_error (GPG_ERR_BAD_SECKEY);
|
||
break;
|
||
}
|
||
|
||
if (!err && r_keytype)
|
||
*r_keytype = keytype;
|
||
|
||
xfree (buf);
|
||
return err;
|
||
}
|
||
|
||
|
||
|
||
/* Delete the key with GRIP from the disk after having asked for
|
||
confirmation using DESC_TEXT. Common error codes are:
|
||
GPG_ERR_NO_SECKEY
|
||
GPG_ERR_KEY_ON_CARD
|
||
GPG_ERR_NOT_CONFIRMED
|
||
*/
|
||
gpg_error_t
|
||
agent_delete_key (ctrl_t ctrl, const char *desc_text,
|
||
const unsigned char *grip)
|
||
{
|
||
gpg_error_t err;
|
||
gcry_sexp_t s_skey = NULL;
|
||
unsigned char *buf = NULL;
|
||
size_t len;
|
||
char *desc_text_final = NULL;
|
||
char *comment = NULL;
|
||
ssh_control_file_t cf = NULL;
|
||
char hexgrip[40+4+1];
|
||
char *default_desc = NULL;
|
||
|
||
err = read_key_file (grip, &s_skey);
|
||
if (gpg_err_code (err) == GPG_ERR_ENOENT)
|
||
err = gpg_error (GPG_ERR_NO_SECKEY);
|
||
if (err)
|
||
goto leave;
|
||
|
||
err = make_canon_sexp (s_skey, &buf, &len);
|
||
if (err)
|
||
goto leave;
|
||
|
||
switch (agent_private_key_type (buf))
|
||
{
|
||
case PRIVATE_KEY_CLEAR:
|
||
case PRIVATE_KEY_OPENPGP_NONE:
|
||
case PRIVATE_KEY_PROTECTED:
|
||
{
|
||
bin2hex (grip, 20, hexgrip);
|
||
if (!desc_text)
|
||
{
|
||
default_desc = xtryasprintf
|
||
("Do you really want to delete the key identified by keygrip%%0A"
|
||
" %s%%0A %%C%%0A?", hexgrip);
|
||
desc_text = default_desc;
|
||
}
|
||
|
||
/* Note, that we will take the comment as a C string for
|
||
display purposes; i.e. all stuff beyond a Nul character is
|
||
ignored. */
|
||
{
|
||
gcry_sexp_t comment_sexp;
|
||
|
||
comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
|
||
if (comment_sexp)
|
||
comment = gcry_sexp_nth_string (comment_sexp, 1);
|
||
gcry_sexp_release (comment_sexp);
|
||
}
|
||
|
||
if (desc_text)
|
||
err = modify_description (desc_text, comment? comment:"", s_skey,
|
||
&desc_text_final);
|
||
if (err)
|
||
goto leave;
|
||
|
||
err = agent_get_confirmation (ctrl, desc_text_final,
|
||
_("Delete key"), _("No"), 0);
|
||
if (err)
|
||
goto leave;
|
||
|
||
cf = ssh_open_control_file ();
|
||
if (cf)
|
||
{
|
||
if (!ssh_search_control_file (cf, hexgrip, NULL, NULL, NULL))
|
||
{
|
||
err = agent_get_confirmation
|
||
(ctrl,
|
||
_("Warning: This key is also listed for use with SSH!\n"
|
||
"Deleting the key might remove your ability to "
|
||
"access remote machines."),
|
||
_("Delete key"), _("No"), 0);
|
||
if (err)
|
||
goto leave;
|
||
}
|
||
}
|
||
|
||
err = remove_key_file (grip);
|
||
}
|
||
break;
|
||
|
||
case PRIVATE_KEY_SHADOWED:
|
||
err = gpg_error (GPG_ERR_KEY_ON_CARD);
|
||
break;
|
||
|
||
default:
|
||
log_error ("invalid private key format\n");
|
||
err = gpg_error (GPG_ERR_BAD_SECKEY);
|
||
break;
|
||
}
|
||
|
||
leave:
|
||
ssh_close_control_file (cf);
|
||
gcry_free (comment);
|
||
xfree (desc_text_final);
|
||
xfree (default_desc);
|
||
xfree (buf);
|
||
gcry_sexp_release (s_skey);
|
||
return err;
|
||
}
|