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-rw-r--r--common/get-passphrase.c255
1 files changed, 255 insertions, 0 deletions
diff --git a/common/get-passphrase.c b/common/get-passphrase.c
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+/* get-passphrase.c - Ask for a passphrase via the agent
+ * Copyright (C) 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ * - the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * or
+ *
+ * - the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * or both in parallel, as here.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <assuan.h>
+
+#include "util.h"
+#include "i18n.h"
+#include "asshelp.h"
+#include "membuf.h"
+#include "sysutils.h"
+#include "get-passphrase.h"
+
+/* The context used by this process to ask for the passphrase. */
+static assuan_context_t agent_ctx;
+static struct
+{
+ gpg_err_source_t errsource;
+ int verbosity;
+ const char *agent_program;
+ const char *lc_ctype;
+ const char *lc_messages;
+ session_env_t session_env;
+ const char *pinentry_user_data;
+} agentargs;
+
+
+/* Set local variable to be used for a possible agent startup. Note
+ that the strings are just pointers and should not anymore be
+ modified by the caller. */
+void
+gnupg_prepare_get_passphrase (gpg_err_source_t errsource,
+ int verbosity,
+ const char *agent_program,
+ const char *opt_lc_ctype,
+ const char *opt_lc_messages,
+ session_env_t session_env)
+{
+ agentargs.errsource = errsource;
+ agentargs.verbosity = verbosity;
+ agentargs.agent_program = agent_program;
+ agentargs.lc_ctype = opt_lc_ctype;
+ agentargs.lc_messages = opt_lc_messages;
+ agentargs.session_env = session_env;
+}
+
+
+/* Try to connect to the agent via socket or fork it off and work by
+ pipes. Handle the server's initial greeting. */
+static gpg_error_t
+start_agent (void)
+{
+ gpg_error_t err;
+
+ /* Fixme: This code is not thread safe, thus we don't build it with
+ pth. We will need a context for each thread or serialize the
+ access to the agent. */
+ if (agent_ctx)
+ return 0;
+
+ err = start_new_gpg_agent (&agent_ctx,
+ agentargs.errsource,
+ agentargs.agent_program,
+ agentargs.lc_ctype,
+ agentargs.lc_messages,
+ agentargs.session_env,
+ 1, agentargs.verbosity, 0, NULL, NULL);
+ if (!err)
+ {
+ /* Tell the agent that we support Pinentry notifications. No
+ error checking so that it will work with older agents. */
+ assuan_transact (agent_ctx, "OPTION allow-pinentry-notify",
+ NULL, NULL, NULL, NULL, NULL, NULL);
+ }
+
+ return err;
+}
+
+
+/* This is the default inquiry callback. It merely handles the
+ Pinentry notification. */
+static gpg_error_t
+default_inq_cb (void *opaque, const char *line)
+{
+ (void)opaque;
+
+ if (!strncmp (line, "PINENTRY_LAUNCHED", 17) && (line[17]==' '||!line[17]))
+ {
+ gnupg_allow_set_foregound_window ((pid_t)strtoul (line+17, NULL, 10));
+ /* We do not return errors to avoid breaking other code. */
+ }
+ else
+ log_debug ("ignoring gpg-agent inquiry '%s'\n", line);
+
+ return 0;
+}
+
+
+/* Ask for a passphrase via gpg-agent. On success the caller needs to
+ free the string stored at R_PASSPHRASE. On error NULL will be
+ stored at R_PASSPHRASE and an appropriate gpg error code is
+ returned. With REPEAT set to 1, gpg-agent will ask the user to
+ repeat the just entered passphrase. CACHE_ID is a gpg-agent style
+ passphrase cache id or NULL. ERR_MSG is a error message to be
+ presented to the user (e.g. "bad passphrase - try again") or NULL.
+ PROMPT is the prompt string to label the entry box, it may be NULL
+ for a default one. DESC_MSG is a longer description to be
+ displayed above the entry box, if may be NULL for a default one.
+ If USE_SECMEM is true, the returned passphrase is returned in
+ secure memory. The length of all these strings is limited; they
+ need to fit in their encoded form into a standard Assuan line (i.e
+ less then about 950 characters). All strings shall be UTF-8. */
+gpg_error_t
+gnupg_get_passphrase (const char *cache_id,
+ const char *err_msg,
+ const char *prompt,
+ const char *desc_msg,
+ int repeat,
+ int check_quality,
+ int use_secmem,
+ char **r_passphrase)
+{
+ gpg_error_t err;
+ char line[ASSUAN_LINELENGTH];
+ const char *arg1 = NULL;
+ char *arg2 = NULL;
+ char *arg3 = NULL;
+ char *arg4 = NULL;
+ membuf_t data;
+
+ *r_passphrase = NULL;
+
+ err = start_agent ();
+ if (err)
+ return err;
+
+ /* Check that the gpg-agent understands the repeat option. */
+ if (assuan_transact (agent_ctx,
+ "GETINFO cmd_has_option GET_PASSPHRASE repeat",
+ NULL, NULL, NULL, NULL, NULL, NULL))
+ return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+ arg1 = cache_id && *cache_id? cache_id:NULL;
+ if (err_msg && *err_msg)
+ if (!(arg2 = percent_plus_escape (err_msg)))
+ goto no_mem;
+ if (prompt && *prompt)
+ if (!(arg3 = percent_plus_escape (prompt)))
+ goto no_mem;
+ if (desc_msg && *desc_msg)
+ if (!(arg4 = percent_plus_escape (desc_msg)))
+ goto no_mem;
+
+ snprintf (line, DIM(line),
+ "GET_PASSPHRASE --data %s--repeat=%d -- %s %s %s %s",
+ check_quality? "--check ":"",
+ repeat,
+ arg1? arg1:"X",
+ arg2? arg2:"X",
+ arg3? arg3:"X",
+ arg4? arg4:"X");
+ xfree (arg2);
+ xfree (arg3);
+ xfree (arg4);
+
+ if (use_secmem)
+ init_membuf_secure (&data, 64);
+ else
+ init_membuf (&data, 64);
+ err = assuan_transact (agent_ctx, line,
+ put_membuf_cb, &data,
+ default_inq_cb, NULL, NULL, NULL);
+
+ /* Older Pinentries return the old assuan error code for canceled
+ which gets translated by libassuan to GPG_ERR_ASS_CANCELED and
+ not to the code for a user cancel. Fix this here. */
+ if (err && gpg_err_source (err)
+ && gpg_err_code (err) == GPG_ERR_ASS_CANCELED)
+ err = gpg_err_make (gpg_err_source (err), GPG_ERR_CANCELED);
+
+ if (err)
+ {
+ void *p;
+ size_t n;
+
+ p = get_membuf (&data, &n);
+ if (p)
+ wipememory (p, n);
+ xfree (p);
+ }
+ else
+ {
+ put_membuf (&data, "", 1);
+ *r_passphrase = get_membuf (&data, NULL);
+ if (!*r_passphrase)
+ err = gpg_error_from_syserror ();
+ }
+ return err;
+ no_mem:
+ err = gpg_error_from_syserror ();
+ xfree (arg2);
+ xfree (arg3);
+ xfree (arg4);
+ return err;
+}
+
+
+/* Flush the passphrase cache with Id CACHE_ID. */
+gpg_error_t
+gnupg_clear_passphrase (const char *cache_id)
+{
+ gpg_error_t err;
+ char line[ASSUAN_LINELENGTH];
+
+ if (!cache_id || !*cache_id)
+ return 0;
+
+ err = start_agent ();
+ if (err)
+ return err;
+
+ snprintf (line, DIM(line), "CLEAR_PASSPHRASE %s", cache_id);
+ return assuan_transact (agent_ctx, line, NULL, NULL,
+ default_inq_cb, NULL, NULL, NULL);
+}