diff options
Diffstat (limited to 'common/get-passphrase.c')
| -rw-r--r-- | common/get-passphrase.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/common/get-passphrase.c b/common/get-passphrase.c new file mode 100644 index 0000000..c24b40e --- /dev/null +++ b/common/get-passphrase.c @@ -0,0 +1,255 @@ +/* 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); +} |