/* engine-assuan.c - Low-level Assuan protocol engine
* Copyright (C) 2009 g10 Code GmbH
*
* This file is part of GPGME.
*
* GPGME is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* GPGME 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, see <https://gnu.org/licenses/>.
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
/*
Note: This engine requires a modern Assuan server which uses
gpg-error codes. In particular there is no backward compatible
mapping of old Assuan error codes implemented.
*/
#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <assert.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#include <errno.h>
#include "gpgme.h"
#include "util.h"
#include "ops.h"
#include "wait.h"
#include "priv-io.h"
#include "sema.h"
#include "assuan.h"
#include "debug.h"
#include "engine-backend.h"
typedef struct
{
int fd; /* FD we talk about. */
int server_fd;/* Server FD for this connection. */
int dir; /* Inbound/Outbound, maybe given implicit? */
void *data; /* Handler-specific data. */
void *tag; /* ID from the user for gpgme_remove_io_callback. */
} iocb_data_t;
/* Engine instance data. */
struct engine_llass
{
assuan_context_t assuan_ctx;
int lc_ctype_set;
int lc_messages_set;
iocb_data_t status_cb;
struct gpgme_io_cbs io_cbs;
/* Hack for old opassuan.c interface, see there the result struct. */
gpg_error_t last_op_err;
/* User provided callbacks. */
struct {
gpgme_assuan_data_cb_t data_cb;
void *data_cb_value;
gpgme_assuan_inquire_cb_t inq_cb;
void *inq_cb_value;
gpgme_assuan_status_cb_t status_cb;
void *status_cb_value;
} user;
/* Option flags. */
struct {
int gpg_agent:1; /* Assume this is a gpg-agent connection. */
} opt;
char request_origin[10]; /* Copy from the CTX. */
};
typedef struct engine_llass *engine_llass_t;
gpg_error_t _gpgme_engine_assuan_last_op_err (void *engine)
{
engine_llass_t llass = engine;
return llass->last_op_err;
}
/* Prototypes. */
static void llass_io_event (void *engine,
gpgme_event_io_t type, void *type_data);
/* return the default home directory. */
static const char *
llass_get_home_dir (void)
{
/* For this engine the home directory is not a filename but a string
used to convey options. The exclamation mark is a marker to show
that this is not a directory name. Options are strings delimited
by a space. The only option defined for now is GPG_AGENT to
enable GPG_AGENT specific commands to send to the server at
connection startup. */
return "!GPG_AGENT";
}
static char *
llass_get_version (const char *file_name)
{
(void)file_name;
return NULL;
}
static const char *
llass_get_req_version (void)
{
return NULL;
}
static void
close_notify_handler (int fd, void *opaque)
{
engine_llass_t llass = opaque;
assert (fd != -1);
if (llass->status_cb.fd == fd)
{
if (llass->status_cb.tag)
llass->io_cbs.remove (llass->status_cb.tag);
llass->status_cb.fd = -1;
llass->status_cb.tag = NULL;
}
}
static gpgme_error_t
llass_cancel (void *engine)
{
engine_llass_t llass = engine;
if (!llass)
return gpg_error (GPG_ERR_INV_VALUE);
if (llass->status_cb.fd != -1)
_gpgme_io_close (llass->status_cb.fd);
if (llass->assuan_ctx)
{
assuan_release (llass->assuan_ctx);
llass->assuan_ctx = NULL;
}
return 0;
}
static gpgme_error_t
llass_cancel_op (void *engine)
{
engine_llass_t llass = engine;
if (!llass)
return gpg_error (GPG_ERR_INV_VALUE);
if (llass->status_cb.fd != -1)
_gpgme_io_close (llass->status_cb.fd);
return 0;
}
static void
llass_release (void *engine)
{
engine_llass_t llass = engine;
if (!llass)
return;
llass_cancel (engine);
free (llass);
}
/* Create a new instance. If HOME_DIR is NULL standard options for use
with gpg-agent are issued. */
static gpgme_error_t
llass_new (void **engine, const char *file_name, const char *home_dir,
const char *version)
{
gpgme_error_t err = 0;
engine_llass_t llass;
char *optstr;
char *env_tty = NULL;
(void)version; /* Not yet used. */
llass = calloc (1, sizeof *llass);
if (!llass)
return gpg_error_from_syserror ();
llass->status_cb.fd = -1;
llass->status_cb.dir = 1;
llass->status_cb.tag = 0;
llass->status_cb.data = llass;
/* Parse_options. */
if (home_dir && *home_dir == '!')
{
home_dir++;
/* Very simple parser only working for the one option we support. */
/* Note that wk promised to write a regression test if this
parser will be extended. */
if (!strncmp (home_dir, "GPG_AGENT", 9)
&& (!home_dir[9] || home_dir[9] == ' '))
llass->opt.gpg_agent = 1;
}
err = assuan_new_ext (&llass->assuan_ctx, GPG_ERR_SOURCE_GPGME,
&_gpgme_assuan_malloc_hooks, _gpgme_assuan_log_cb,
NULL);
if (err)
goto leave;
assuan_ctx_set_system_hooks (llass->assuan_ctx, &_gpgme_assuan_system_hooks);
assuan_set_flag (llass->assuan_ctx, ASSUAN_CONVEY_COMMENTS, 1);
err = assuan_socket_connect (llass->assuan_ctx, file_name, 0, 0);
if (err)
goto leave;
if (llass->opt.gpg_agent)
{
char *dft_display = NULL;
err = _gpgme_getenv ("DISPLAY", &dft_display);
if (err)
goto leave;
if (dft_display)
{
if (gpgrt_asprintf (&optstr, "OPTION display=%s", dft_display) < 0)
{
err = gpg_error_from_syserror ();
free (dft_display);
goto leave;
}
free (dft_display);
err = assuan_transact (llass->assuan_ctx, optstr, NULL, NULL, NULL,
NULL, NULL, NULL);
gpgrt_free (optstr);
if (err)
goto leave;
}
}
if (llass->opt.gpg_agent)
err = _gpgme_getenv ("GPG_TTY", &env_tty);
if (llass->opt.gpg_agent && (isatty (1) || env_tty || err))
{
int rc = 0;
char dft_ttyname[64];
char *dft_ttytype = NULL;
if (err)
goto leave;
else if (env_tty)
{
snprintf (dft_ttyname, sizeof (dft_ttyname), "%s", env_tty);
free (env_tty);
}
else
rc = ttyname_r (1, dft_ttyname, sizeof (dft_ttyname));
/* Even though isatty() returns 1, ttyname_r() may fail in many
ways, e.g., when /dev/pts is not accessible under chroot. */
if (!rc)
{
if (gpgrt_asprintf (&optstr, "OPTION ttyname=%s", dft_ttyname) < 0)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = assuan_transact (llass->assuan_ctx, optstr, NULL, NULL, NULL,
NULL, NULL, NULL);
gpgrt_free (optstr);
if (err)
goto leave;
err = _gpgme_getenv ("TERM", &dft_ttytype);
if (err)
goto leave;
if (dft_ttytype)
{
if (gpgrt_asprintf (&optstr, "OPTION ttytype=%s", dft_ttytype)< 0)
{
err = gpg_error_from_syserror ();
free (dft_ttytype);
goto leave;
}
free (dft_ttytype);
err = assuan_transact (llass->assuan_ctx, optstr, NULL, NULL,
NULL, NULL, NULL, NULL);
gpgrt_free (optstr);
if (err)
goto leave;
}
}
}
#ifdef HAVE_W32_SYSTEM
/* Under Windows we need to use AllowSetForegroundWindow. Tell
llass to tell us when it needs it. */
if (!err && llass->opt.gpg_agent)
{
err = assuan_transact (llass->assuan_ctx, "OPTION allow-pinentry-notify",
NULL, NULL, NULL, NULL, NULL, NULL);
if (gpg_err_code (err) == GPG_ERR_UNKNOWN_OPTION)
err = 0; /* This work only with recent gpg-agents. */
}
#endif /*HAVE_W32_SYSTEM*/
leave:
/* Close the server ends of the pipes (because of this, we must use
the stored server_fd_str in the function start). Our ends are
closed in llass_release(). */
if (err)
llass_release (llass);
else
*engine = llass;
return err;
}
/* Copy flags from CTX into the engine object. */
static void
llass_set_engine_flags (void *engine, const gpgme_ctx_t ctx)
{
engine_llass_t llass = engine;
if (ctx->request_origin)
{
if (strlen (ctx->request_origin) + 1 > sizeof llass->request_origin)
strcpy (llass->request_origin, "xxx"); /* Too long - force error */
else
strcpy (llass->request_origin, ctx->request_origin);
}
else
*llass->request_origin = 0;
}
static gpgme_error_t
llass_set_locale (void *engine, int category, const char *value)
{
gpgme_error_t err;
engine_llass_t llass = engine;
char *optstr;
const char *catstr;
if (!llass->opt.gpg_agent)
return 0;
/* FIXME: If value is NULL, we need to reset the option to default.
But we can't do this. So we error out here. gpg-agent needs
support for this. */
if (0)
;
#ifdef LC_CTYPE
else if (category == LC_CTYPE)
{
catstr = "lc-ctype";
if (!value && llass->lc_ctype_set)
return gpg_error (GPG_ERR_INV_VALUE);
if (value)
llass->lc_ctype_set = 1;
}
#endif
#ifdef LC_MESSAGES
else if (category == LC_MESSAGES)
{
catstr = "lc-messages";
if (!value && llass->lc_messages_set)
return gpg_error (GPG_ERR_INV_VALUE);
if (value)
llass->lc_messages_set = 1;
}
#endif /* LC_MESSAGES */
else
return gpg_error (GPG_ERR_INV_VALUE);
/* FIXME: Reset value to default. */
if (!value)
return 0;
if (gpgrt_asprintf (&optstr, "OPTION %s=%s", catstr, value) < 0)
err = gpg_error_from_syserror ();
else
{
err = assuan_transact (llass->assuan_ctx, optstr, NULL, NULL,
NULL, NULL, NULL, NULL);
gpgrt_free (optstr);
}
return err;
}
/* This is the inquiry callback. It handles stuff which ee need to
handle here and passes everything on to the user callback. */
static gpgme_error_t
inquire_cb (engine_llass_t llass, const char *keyword, const char *args)
{
gpg_error_t err;
if (llass->opt.gpg_agent && !strcmp (keyword, "PINENTRY_LAUNCHED"))
{
_gpgme_allow_set_foreground_window ((pid_t)strtoul (args, NULL, 10));
}
if (llass->user.inq_cb)
{
gpgme_data_t data = NULL;
err = llass->user.inq_cb (llass->user.inq_cb_value,
keyword, args, &data);
if (!err && data)
{
/* FIXME: Returning data is not yet implemented. However we
need to allow the caller to cleanup his data object.
Thus we run the callback in finish mode immediately. */
err = llass->user.inq_cb (llass->user.inq_cb_value,
NULL, NULL, &data);
}
}
else
err = 0;
return err;
}
static gpgme_error_t
llass_status_handler (void *opaque, int fd)
{
struct io_cb_data *data = (struct io_cb_data *) opaque;
engine_llass_t llass = (engine_llass_t) data->handler_value;
gpgme_error_t err = 0;
char *line;
size_t linelen;
do
{
err = assuan_read_line (llass->assuan_ctx, &line, &linelen);
if (err)
{
/* Reading a full line may not be possible when
communicating over a socket in nonblocking mode. In this
case, we are done for now. */
if (gpg_err_code (err) == GPG_ERR_EAGAIN)
{
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: EAGAIN reading assuan line (ignored)", fd);
err = 0;
continue;
}
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: error reading assuan line: %s",
fd, gpg_strerror (err));
}
else if (linelen >= 2 && line[0] == 'D' && line[1] == ' ')
{
char *src = line + 2;
char *end = line + linelen;
char *dst = src;
linelen = 0;
while (src < end)
{
if (*src == '%' && src + 2 < end)
{
/* Handle escaped characters. */
++src;
*dst++ = _gpgme_hextobyte (src);
src += 2;
}
else
*dst++ = *src++;
linelen++;
}
src = line + 2;
if (linelen && llass->user.data_cb)
err = llass->user.data_cb (llass->user.data_cb_value,
src, linelen);
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: D inlinedata; status from cb: %s",
fd, (llass->user.data_cb ?
(err? gpg_strerror (err):"ok"):"no callback"));
}
else if (linelen >= 3
&& line[0] == 'E' && line[1] == 'N' && line[2] == 'D'
&& (line[3] == '\0' || line[3] == ' '))
{
/* END received. Tell the data callback. */
if (llass->user.data_cb)
err = llass->user.data_cb (llass->user.data_cb_value, NULL, 0);
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: END line; status from cb: %s",
fd, (llass->user.data_cb ?
(err? gpg_strerror (err):"ok"):"no callback"));
}
else if (linelen > 2 && line[0] == 'S' && line[1] == ' ')
{
char *args;
char *src;
for (src=line+2; *src == ' '; src++)
;
args = strchr (src, ' ');
if (!args)
args = line + linelen; /* Let it point to an empty string. */
else
*(args++) = 0;
while (*args == ' ')
args++;
if (llass->user.status_cb)
err = llass->user.status_cb (llass->user.status_cb_value,
src, args);
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: S line (%s) - status from cb: %s",
fd, line+2, (llass->user.status_cb ?
(err? gpg_strerror (err):"ok"):"no callback"));
}
else if (linelen >= 7
&& line[0] == 'I' && line[1] == 'N' && line[2] == 'Q'
&& line[3] == 'U' && line[4] == 'I' && line[5] == 'R'
&& line[6] == 'E'
&& (line[7] == '\0' || line[7] == ' '))
{
char *src;
char *args;
for (src=line+7; *src == ' '; src++)
;
args = strchr (src, ' ');
if (!args)
args = line + linelen; /* Let it point to an empty string. */
else
*(args++) = 0;
while (*args == ' ')
args++;
err = inquire_cb (llass, src, args);
if (!err)
{
/* Flush and send END. */
err = assuan_send_data (llass->assuan_ctx, NULL, 0);
}
else if (gpg_err_code (err) == GPG_ERR_ASS_CANCELED)
{
/* Flush and send CANcel. */
err = assuan_send_data (llass->assuan_ctx, NULL, 1);
}
}
else if (linelen >= 3
&& line[0] == 'E' && line[1] == 'R' && line[2] == 'R'
&& (line[3] == '\0' || line[3] == ' '))
{
if (line[3] == ' ')
err = atoi (line+4);
else
err = gpg_error (GPG_ERR_GENERAL);
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: ERR line: %s",
fd, err ? gpg_strerror (err) : "ok");
/* Command execution errors are not fatal, as we use
a session based protocol. */
data->op_err = err;
llass->last_op_err = err;
/* The caller will do the rest (namely, call cancel_op,
which closes status_fd). */
return 0;
}
else if (linelen >= 2
&& line[0] == 'O' && line[1] == 'K'
&& (line[2] == '\0' || line[2] == ' '))
{
TRACE (DEBUG_CTX, "gpgme:llass_status_handler", llass,
"fd 0x%x: OK line", fd);
llass->last_op_err = 0;
_gpgme_io_close (llass->status_cb.fd);
return 0;
}
else
{
/* Comment line or invalid line. */
}
}
while (!err && assuan_pending_line (llass->assuan_ctx));
return err;
}
static gpgme_error_t
add_io_cb (engine_llass_t llass, iocb_data_t *iocbd, gpgme_io_cb_t handler)
{
gpgme_error_t err;
TRACE_BEG (DEBUG_ENGINE, "engine-assuan:add_io_cb", llass,
"fd=%d, dir %d", iocbd->fd, iocbd->dir);
err = (*llass->io_cbs.add) (llass->io_cbs.add_priv,
iocbd->fd, iocbd->dir,
handler, iocbd->data, &iocbd->tag);
if (err)
return TRACE_ERR (err);
if (!iocbd->dir)
/* FIXME Kludge around poll() problem. */
err = _gpgme_io_set_nonblocking (iocbd->fd);
return TRACE_ERR (err);
}
static gpgme_error_t
start (engine_llass_t llass, const char *command)
{
gpgme_error_t err;
assuan_fd_t afdlist[5];
int fdlist[5];
int nfds;
int i;
if (*llass->request_origin && llass->opt.gpg_agent)
{
char *cmd;
cmd = _gpgme_strconcat ("OPTION pretend-request-origin=",
llass->request_origin, NULL);
if (!cmd)
return gpg_error_from_syserror ();
err = assuan_transact (llass->assuan_ctx, cmd, NULL, NULL, NULL,
NULL, NULL, NULL);
free (cmd);
if (err && gpg_err_code (err) != GPG_ERR_UNKNOWN_OPTION)
return err;
}
/* We need to know the fd used by assuan for reads. We do this by
using the assumption that the first returned fd from
assuan_get_active_fds() is always this one. */
nfds = assuan_get_active_fds (llass->assuan_ctx, 0 /* read fds */,
afdlist, DIM (afdlist));
if (nfds < 1)
return gpg_error (GPG_ERR_GENERAL); /* FIXME */
/* For now... */
for (i = 0; i < nfds; i++)
fdlist[i] = (int) afdlist[i];
/* We "duplicate" the file descriptor, so we can close it here (we
can't close fdlist[0], as that is closed by libassuan, and
closing it here might cause libassuan to close some unrelated FD
later). Alternatively, we could special case status_fd and
register/unregister it manually as needed, but this increases
code duplication and is more complicated as we can not use the
close notifications etc. A third alternative would be to let
Assuan know that we closed the FD, but that complicates the
Assuan interface. */
llass->status_cb.fd = _gpgme_io_dup (fdlist[0]);
if (llass->status_cb.fd < 0)
return gpg_error_from_syserror ();
if (_gpgme_io_set_close_notify (llass->status_cb.fd,
close_notify_handler, llass))
{
_gpgme_io_close (llass->status_cb.fd);
llass->status_cb.fd = -1;
return gpg_error (GPG_ERR_GENERAL);
}
err = add_io_cb (llass, &llass->status_cb, llass_status_handler);
if (!err)
err = assuan_write_line (llass->assuan_ctx, command);
/* FIXME: If *command == '#' no answer is expected. */
if (!err)
llass_io_event (llass, GPGME_EVENT_START, NULL);
return err;
}
static gpgme_error_t
llass_transact (void *engine,
const char *command,
gpgme_assuan_data_cb_t data_cb,
void *data_cb_value,
gpgme_assuan_inquire_cb_t inq_cb,
void *inq_cb_value,
gpgme_assuan_status_cb_t status_cb,
void *status_cb_value)
{
engine_llass_t llass = engine;
gpgme_error_t err;
if (!llass || !command || !*command)
return gpg_error (GPG_ERR_INV_VALUE);
llass->user.data_cb = data_cb;
llass->user.data_cb_value = data_cb_value;
llass->user.inq_cb = inq_cb;
llass->user.inq_cb_value = inq_cb_value;
llass->user.status_cb = status_cb;
llass->user.status_cb_value = status_cb_value;
err = start (llass, command);
return err;
}
static void
llass_set_io_cbs (void *engine, gpgme_io_cbs_t io_cbs)
{
engine_llass_t llass = engine;
llass->io_cbs = *io_cbs;
}
static void
llass_io_event (void *engine, gpgme_event_io_t type, void *type_data)
{
engine_llass_t llass = engine;
TRACE (DEBUG_ENGINE, "gpgme:llass_io_event", llass,
"event %p, type %d, type_data %p",
llass->io_cbs.event, type, type_data);
if (llass->io_cbs.event)
(*llass->io_cbs.event) (llass->io_cbs.event_priv, type, type_data);
}
struct engine_ops _gpgme_engine_ops_assuan =
{
/* Static functions. */
_gpgme_get_default_agent_socket,
llass_get_home_dir,
llass_get_version,
llass_get_req_version,
llass_new,
/* Member functions. */
llass_release,
NULL, /* reset */
NULL, /* set_status_cb */
NULL, /* set_status_handler */
NULL, /* set_command_handler */
NULL, /* set_colon_line_handler */
llass_set_locale,
NULL, /* set_protocol */
llass_set_engine_flags,
NULL, /* decrypt */
NULL, /* delete */
NULL, /* edit */
NULL, /* encrypt */
NULL, /* encrypt_sign */
NULL, /* export */
NULL, /* export_ext */
NULL, /* genkey */
NULL, /* import */
NULL, /* keylist */
NULL, /* keylist_ext */
NULL, /* keylist_data */
NULL, /* keysign */
NULL, /* tofu_policy */
NULL, /* sign */
NULL, /* trustlist */
NULL, /* verify */
NULL, /* getauditlog */
llass_transact, /* opassuan_transact */
NULL, /* conf_load */
NULL, /* conf_save */
NULL, /* conf_dir */
NULL, /* query_swdb */
llass_set_io_cbs,
llass_io_event,
llass_cancel,
llass_cancel_op,
NULL, /* passwd */
NULL, /* set_pinentry_mode */
NULL /* opspawn */
};