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simple-pwquery.c
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/* simple-pwquery.c - A simple password query client for gpg-agent
* Copyright (C) 2002, 2004, 2007 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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/>.
*/
/* This module is intended as a simple client implementation to
gpg-agent's GET_PASSPHRASE command. It can only cope with an
already running gpg-agent. Some stuff is configurable in the
header file. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <assuan.h>
#ifdef HAVE_W32_SYSTEM
#include <winsock2.h>
#else
#include <sys/socket.h>
#include <sys/un.h>
#endif
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#define GNUPG_COMMON_NEED_AFLOCAL
#include "../common/mischelp.h"
#include "sysutils.h"
#include "membuf.h"
#define SIMPLE_PWQUERY_IMPLEMENTATION 1
#include "simple-pwquery.h"
#define SPWQ_OUT_OF_CORE gpg_error_from_errno (ENOMEM)
#define SPWQ_IO_ERROR gpg_error_from_errno (EIO)
#define SPWQ_PROTOCOL_ERROR gpg_error (GPG_ERR_PROTOCOL_VIOLATION)
#define SPWQ_ERR_RESPONSE gpg_error (GPG_ERR_INV_RESPONSE)
#define SPWQ_NO_AGENT gpg_error (GPG_ERR_NO_AGENT)
#define SPWQ_SYS_ERROR gpg_error_from_syserror ()
#define SPWQ_GENERAL_ERROR gpg_error (GPG_ERR_GENERAL)
#define SPWQ_NO_PIN_ENTRY gpg_error (GPG_ERR_NO_PIN_ENTRY)
#ifndef _
#define _(a) (a)
#endif
#if !defined (hexdigitp) && !defined (xtoi_2)
#define digitp(p) (*(p) >= '0' && *(p) <= '9')
#define hexdigitp(a) (digitp (a) \
|| (*(a) >= 'A' && *(a) <= 'F') \
|| (*(a) >= 'a' && *(a) <= 'f'))
#define xtoi_1(p) (*(p) <= '9'? (*(p)- '0'): \
*(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
#define xtoi_2(p) ((xtoi_1(p) * 16) + xtoi_1((p)+1))
#endif
/* Name of the socket to be used. This is a kludge to keep on using
the existsing code despite that we only support a standard socket. */
static char *default_gpg_agent_info;
#ifndef HAVE_STPCPY
static char *
my_stpcpy(char *a,const char *b)
{
while( *b )
*a++ = *b++;
*a = 0;
return (char*)a;
}
#define stpcpy(a,b) my_stpcpy((a), (b))
#endif
/* Send an option to the agent */
static int
agent_send_option (assuan_context_t ctx, const char *name, const char *value)
{
int err;
char *line;
line = spwq_malloc (7 + strlen (name) + 1 + strlen (value) + 2);
if (!line)
return SPWQ_OUT_OF_CORE;
strcpy (stpcpy (stpcpy (stpcpy (
stpcpy (line, "OPTION "), name), "="), value), "\n");
err = assuan_transact (ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
spwq_free (line);
return err;
}
/* Send all available options to the agent. */
static int
agent_send_all_options (assuan_context_t ctx)
{
char *dft_display = NULL;
char *dft_ttyname = NULL;
char *dft_ttytype = NULL;
char *dft_xauthority = NULL;
char *dft_pinentry_user_data = NULL;
int rc = 0;
dft_display = getenv ("DISPLAY");
if (dft_display)
{
if ((rc = agent_send_option (ctx, "display", dft_display)))
return rc;
}
dft_ttyname = getenv ("GPG_TTY");
#if !defined(HAVE_W32_SYSTEM) && !defined(HAVE_BROKEN_TTYNAME)
if ((!dft_ttyname || !*dft_ttyname) && ttyname (0))
dft_ttyname = ttyname (0);
#endif
if (dft_ttyname && *dft_ttyname)
{
if ((rc=agent_send_option (ctx, "ttyname", dft_ttyname)))
return rc;
}
dft_ttytype = getenv ("TERM");
if (dft_ttyname && dft_ttytype)
{
if ((rc = agent_send_option (ctx, "ttytype", dft_ttytype)))
return rc;
}
#if defined(HAVE_SETLOCALE)
{
char *old_lc = NULL;
char *dft_lc = NULL;
#if defined(LC_CTYPE)
old_lc = setlocale (LC_CTYPE, NULL);
if (old_lc)
{
char *p = spwq_malloc (strlen (old_lc)+1);
if (!p)
return SPWQ_OUT_OF_CORE;
strcpy (p, old_lc);
old_lc = p;
}
dft_lc = setlocale (LC_CTYPE, "");
if (dft_ttyname && dft_lc)
rc = agent_send_option (ctx, "lc-ctype", dft_lc);
if (old_lc)
{
setlocale (LC_CTYPE, old_lc);
spwq_free (old_lc);
}
if (rc)
return rc;
#endif
#if defined(LC_MESSAGES)
old_lc = setlocale (LC_MESSAGES, NULL);
if (old_lc)
{
char *p = spwq_malloc (strlen (old_lc)+1);
if (!p)
return SPWQ_OUT_OF_CORE;
strcpy (p, old_lc);
old_lc = p;
}
dft_lc = setlocale (LC_MESSAGES, "");
if (dft_ttyname && dft_lc)
rc = agent_send_option (ctx, "lc-messages", dft_lc);
if (old_lc)
{
setlocale (LC_MESSAGES, old_lc);
spwq_free (old_lc);
}
if (rc)
return rc;
#endif
}
#endif /*HAVE_SETLOCALE*/
/* Send the XAUTHORITY variable. */
dft_xauthority = getenv ("XAUTHORITY");
if (dft_xauthority)
{
/* We ignore errors here because older gpg-agents don't support
this option. */
agent_send_option (ctx, "xauthority", dft_xauthority);
}
/* Send the PINENTRY_USER_DATA variable. */
dft_pinentry_user_data = getenv ("PINENTRY_USER_DATA");
if (dft_pinentry_user_data)
{
/* We ignore errors here because older gpg-agents don't support
this option. */
agent_send_option (ctx, "pinentry-user-data", dft_pinentry_user_data);
}
/* Tell the agent that we support Pinentry notifications. No
error checking so that it will work with older agents. */
assuan_transact (ctx, "OPTION allow-pinentry-notify",
NULL, NULL, NULL, NULL, NULL, NULL);
return 0;
}
/* Try to open a connection to the agent, send all options and return
the file descriptor for the connection. Return -1 in case of
error. */
static int
agent_open (assuan_context_t *ctx)
{
int rc;
char *infostr;
infostr = default_gpg_agent_info;
if ( !infostr || !*infostr )
{
#ifdef SPWQ_USE_LOGGING
log_error (_("no gpg-agent running in this session\n"));
#endif
*ctx = NULL;
return SPWQ_NO_AGENT;
}
rc = assuan_new (ctx);
if (rc)
return rc;
rc = assuan_socket_connect (*ctx, infostr, 0, 0);
if (rc)
{
#ifdef SPWQ_USE_LOGGING
log_error (_("can't connect to '%s': %s\n"),
infostr, gpg_strerror (rc));
#endif
goto errout;
}
rc = agent_send_all_options (*ctx);
if (rc)
{
#ifdef SPWQ_USE_LOGGING
log_error (_("problem setting the gpg-agent options\n"));
#endif
goto errout;
}
return 0;
errout:
assuan_release (*ctx);
*ctx = NULL;
return rc;
}
/* Copy text to BUFFER and escape as required. Return a pointer to
the end of the new buffer. Note that BUFFER must be large enough
to keep the entire text; allocataing it 3 times the size of TEXT
is sufficient. */
static char *
copy_and_escape (char *buffer, const char *text)
{
int i;
const unsigned char *s = (unsigned char *)text;
char *p = buffer;
for (i=0; s[i]; i++)
{
if (s[i] < ' ' || s[i] == '+')
{
sprintf (p, "%%%02X", s[i]);
p += 3;
}
else if (s[i] == ' ')
*p++ = '+';
else
*p++ = s[i];
}
return p;
}
/* Set the name of the default socket to NAME. */
int
simple_pw_set_socket (const char *name)
{
spwq_free (default_gpg_agent_info);
default_gpg_agent_info = NULL;
if (name)
{
default_gpg_agent_info = spwq_malloc (strlen (name) + 1);
if (!default_gpg_agent_info)
return SPWQ_OUT_OF_CORE;
strcpy (default_gpg_agent_info, name);
}
return 0;
}
/* 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
{
#ifdef SPWQ_USE_LOGGING
log_debug ("ignoring gpg-agent inquiry '%s'\n", line);
#endif
}
return 0;
}
/* Ask the gpg-agent for a passphrase and present the user with a
DESCRIPTION, a PROMPT and optionally with a TRYAGAIN extra text.
If a CACHEID is not NULL it is used to locate the passphrase in
the cache and store it under this ID. If OPT_CHECK is true
gpg-agent is asked to apply some checks on the passphrase security.
If ERRORCODE is not NULL it should point a variable receiving an
errorcode; this error code might be 0 if the user canceled the
operation. The function returns NULL to indicate an error. */
char *
simple_pwquery (const char *cacheid,
const char *tryagain,
const char *prompt,
const char *description,
int opt_check,
int *errorcode)
{
int rc;
assuan_context_t ctx;
membuf_t data;
char *result = NULL;
char *pw = NULL;
char *p;
size_t n;
rc = agent_open (&ctx);
if (rc)
goto leave;
if (!cacheid)
cacheid = "X";
if (!tryagain)
tryagain = "X";
if (!prompt)
prompt = "X";
if (!description)
description = "X";
{
char *line;
/* We allocate 3 times the needed space so that there is enough
space for escaping. */
line = spwq_malloc (15 + 10
+ 3*strlen (cacheid) + 1
+ 3*strlen (tryagain) + 1
+ 3*strlen (prompt) + 1
+ 3*strlen (description) + 1
+ 2);
if (!line)
{
rc = SPWQ_OUT_OF_CORE;
goto leave;
}
strcpy (line, "GET_PASSPHRASE ");
p = line+15;
if (opt_check)
p = stpcpy (p, "--check ");
p = copy_and_escape (p, cacheid);
*p++ = ' ';
p = copy_and_escape (p, tryagain);
*p++ = ' ';
p = copy_and_escape (p, prompt);
*p++ = ' ';
p = copy_and_escape (p, description);
*p++ = '\n';
init_membuf_secure (&data, 64);
rc = assuan_transact (ctx, line, put_membuf_cb, &data,
default_inq_cb, NULL, NULL, NULL);
spwq_free (line);
/* 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 (rc && gpg_err_source (rc)
&& gpg_err_code (rc) == GPG_ERR_ASS_CANCELED)
rc = gpg_err_make (gpg_err_source (rc), GPG_ERR_CANCELED);
if (rc)
{
p = get_membuf (&data, &n);
if (p)
wipememory (p, n);
spwq_free (p);
}
else
{
put_membuf (&data, "", 1);
result = get_membuf (&data, NULL);
if (pw == NULL)
rc = gpg_error_from_syserror ();
}
}
leave:
if (errorcode)
*errorcode = rc;
assuan_release (ctx);
return result;
}
/* Ask the gpg-agent to clear the passphrase for the cache ID CACHEID. */
int
simple_pwclear (const char *cacheid)
{
char line[500];
char *p;
/* We need not more than 50 characters for the command and the
terminating nul. */
if (strlen (cacheid) * 3 > sizeof (line) - 50)
return SPWQ_PROTOCOL_ERROR;
strcpy (line, "CLEAR_PASSPHRASE ");
p = line + 17;
p = copy_and_escape (p, cacheid);
*p++ = '\n';
*p++ = '\0';
return simple_query (line);
}
/* Perform the simple query QUERY (which must be new-line and 0
terminated) and return the error code. */
int
simple_query (const char *query)
{
assuan_context_t ctx;
int rc;
rc = agent_open (&ctx);
if (rc)
return rc;
rc = assuan_transact (ctx, query, NULL, NULL, NULL, NULL, NULL, NULL);
assuan_release (ctx);
return rc;
}

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