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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 <http://www.gnu.org/licenses/>.
*/
/* This module is intended as a standalone client implementation to
gpg-agent's GET_PASSPHRASE command. In particular it does not use
the Assuan library and 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>
#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
#ifdef HAVE_W32_SYSTEM
#include "../jnlib/w32-afunix.h"
#endif
#define SIMPLE_PWQUERY_IMPLEMENTATION 1
#include "simple-pwquery.h"
#if defined(SPWQ_USE_LOGGING) && !defined(HAVE_JNLIB_LOGGING)
# undef SPWQ_USE_LOGGING
#endif
#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 if GPG_AGENT_INFO has not been
set. No default socket is used if this is NULL. */
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
/* Write NBYTES of BUF to file descriptor FD. */
static int
writen (int fd, const void *buf, size_t nbytes)
{
size_t nleft = nbytes;
int nwritten;
while (nleft > 0)
{
#ifdef HAVE_W32_SYSTEM
nwritten = send (fd, buf, nleft, 0);
#else
nwritten = write (fd, buf, nleft);
#endif
if (nwritten < 0)
{
if (errno == EINTR)
nwritten = 0;
else {
#ifdef SPWQ_USE_LOGGING
log_error ("write failed: %s\n", strerror (errno));
#endif
return SPWQ_IO_ERROR;
}
}
nleft -= nwritten;
buf = (const char*)buf + nwritten;
}
return 0;
}
/* Read an entire line and return number of bytes read. */
static int
readline (int fd, char *buf, size_t buflen)
{
size_t nleft = buflen;
char *p;
int nread = 0;
while (nleft > 0)
{
#ifdef HAVE_W32_SYSTEM
int n = recv (fd, buf, nleft, 0);
#else
int n = read (fd, buf, nleft);
#endif
if (n < 0)
{
if (errno == EINTR)
continue;
return -(SPWQ_IO_ERROR);
}
else if (!n)
{
return -(SPWQ_PROTOCOL_ERROR); /* incomplete line */
}
p = buf;
nleft -= n;
buf += n;
nread += n;
for (; n && *p != '\n'; n--, p++)
;
if (n)
{
break; /* At least one full line available - that's enough.
This function is just a simple implementation, so
it is okay to forget about pending bytes. */
}
}
return nread;
}
/* Send an option to the agent */
static int
agent_send_option (int fd, const char *name, const char *value)
{
char buf[200];
int nread;
char *line;
int i;
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");
i = writen (fd, line, strlen (line));
spwq_free (line);
if (i)
return i;
/* get response */
nread = readline (fd, buf, DIM(buf)-1);
if (nread < 0)
return -nread;
if (nread < 3)
return SPWQ_PROTOCOL_ERROR;
if (buf[0] == 'O' && buf[1] == 'K' && (buf[2] == ' ' || buf[2] == '\n'))
return 0; /* okay */
return SPWQ_ERR_RESPONSE;
}
/* Send all available options to the agent. */
static int
agent_send_all_options (int fd)
{
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 (fd, "display", dft_display)))
return rc;
}
dft_ttyname = getenv ("GPG_TTY");
#ifndef HAVE_W32_SYSTEM
if ((!dft_ttyname || !*dft_ttyname) && ttyname (0))
dft_ttyname = ttyname (0);
#endif
if (dft_ttyname && *dft_ttyname)
{
if ((rc=agent_send_option (fd, "ttyname", dft_ttyname)))
return rc;
}
dft_ttytype = getenv ("TERM");
if (dft_ttyname && dft_ttytype)
{
if ((rc = agent_send_option (fd, "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 (fd, "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 (fd, "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 (fd, "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 (fd, "pinentry-user-data", dft_pinentry_user_data);
}
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 (int *rfd)
{
int rc;
int fd;
char *infostr, *p;
struct sockaddr_un client_addr;
size_t len;
int prot;
char line[200];
int nread;
*rfd = -1;
infostr = getenv ( "GPG_AGENT_INFO" );
if ( !infostr || !*infostr )
infostr = default_gpg_agent_info;
if ( !infostr || !*infostr )
{
#ifdef SPWQ_USE_LOGGING
log_error (_("gpg-agent is not available in this session\n"));
#endif
return SPWQ_NO_AGENT;
}
p = spwq_malloc (strlen (infostr)+1);
if (!p)
return SPWQ_OUT_OF_CORE;
strcpy (p, infostr);
infostr = p;
if ( !(p = strchr ( infostr, PATHSEP_C)) || p == infostr
|| (p-infostr)+1 >= sizeof client_addr.sun_path )
{
#ifdef SPWQ_USE_LOGGING
log_error ( _("malformed GPG_AGENT_INFO environment variable\n"));
#endif
return SPWQ_NO_AGENT;
}
*p++ = 0;
while (*p && *p != PATHSEP_C)
p++;
prot = *p? atoi (p+1) : 0;
if ( prot != 1)
{
#ifdef SPWQ_USE_LOGGING
log_error (_("gpg-agent protocol version %d is not supported\n"),prot);
#endif
return SPWQ_PROTOCOL_ERROR;
}
#ifdef HAVE_W32_SYSTEM
fd = _w32_sock_new (AF_UNIX, SOCK_STREAM, 0);
#else
fd = socket (AF_UNIX, SOCK_STREAM, 0);
#endif
if (fd == -1)
{
#ifdef SPWQ_USE_LOGGING
log_error ("can't create socket: %s\n", strerror(errno) );
#endif
return SPWQ_SYS_ERROR;
}
memset (&client_addr, 0, sizeof client_addr);
client_addr.sun_family = AF_UNIX;
strcpy (client_addr.sun_path, infostr);
len = (offsetof (struct sockaddr_un, sun_path)
+ strlen(client_addr.sun_path) + 1);
#ifdef HAVE_W32_SYSTEM
rc = _w32_sock_connect (fd, (struct sockaddr*)&client_addr, len );
#else
rc = connect (fd, (struct sockaddr*)&client_addr, len );
#endif
if (rc == -1)
{
#ifdef SPWQ_USE_LOGGING
log_error ( _("can't connect to `%s': %s\n"), infostr, strerror (errno));
#endif
close (fd );
return SPWQ_IO_ERROR;
}
nread = readline (fd, line, DIM(line));
if (nread < 3 || !(line[0] == 'O' && line[1] == 'K'
&& (line[2] == '\n' || line[2] == ' ')) )
{
#ifdef SPWQ_USE_LOGGING
log_error ( _("communication problem with gpg-agent\n"));
#endif
close (fd );
return SPWQ_PROTOCOL_ERROR;
}
rc = agent_send_all_options (fd);
if (rc)
{
#ifdef SPWQ_USE_LOGGING
log_error (_("problem setting the gpg-agent options\n"));
#endif
close (fd);
return rc;
}
*rfd = fd;
return 0;
}
/* 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);
if (name)
{
default_gpg_agent_info = spwq_malloc (strlen (name) + 4 + 1);
if (!default_gpg_agent_info)
return SPWQ_OUT_OF_CORE;
/* We don't know the PID thus we use 0. */
strcpy (stpcpy (default_gpg_agent_info, name),
PATHSEP_S "0" PATHSEP_S "1");
}
else
default_gpg_agent_info = NULL;
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 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 fd = -1;
int nread;
char *result = NULL;
char *pw = NULL;
char *p;
int rc, i;
rc = agent_open (&fd);
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';
rc = writen (fd, line, p - line);
spwq_free (line);
if (rc)
goto leave;
}
/* get response */
pw = spwq_secure_malloc (500);
nread = readline (fd, pw, 499);
if (nread < 0)
{
rc = -nread;
goto leave;
}
if (nread < 3)
{
rc = SPWQ_PROTOCOL_ERROR;
goto leave;
}
if (pw[0] == 'O' && pw[1] == 'K' && pw[2] == ' ')
{ /* we got a passphrase - convert it back from hex */
size_t pwlen = 0;
for (i=3; i < nread && hexdigitp (pw+i); i+=2)
pw[pwlen++] = xtoi_2 (pw+i);
pw[pwlen] = 0; /* make a C String */
result = pw;
pw = NULL;
}
else if ((nread > 7 && !memcmp (pw, "ERR 111", 7)
&& (pw[7] == ' ' || pw[7] == '\n') )
|| ((nread > 4 && !memcmp (pw, "ERR ", 4)
&& (strtoul (pw+4, NULL, 0) & 0xffff) == 99)) )
{
/* 111 is the old Assuan code for canceled which might still
be in use by old installations. 99 is GPG_ERR_CANCELED as
used by modern gpg-agents; 0xffff is used to mask out the
error source. */
#ifdef SPWQ_USE_LOGGING
log_info (_("canceled by user\n") );
#endif
*errorcode = 0; /* Special error code to indicate Cancel. */
}
else if (nread > 4 && !memcmp (pw, "ERR ", 4))
{
switch ( (strtoul (pw+4, NULL, 0) & 0xffff) )
{
case 85: rc = SPWQ_NO_PIN_ENTRY; break;
default: rc = SPWQ_GENERAL_ERROR; break;
}
}
else
{
#ifdef SPWQ_USE_LOGGING
log_error (_("problem with the agent\n"));
#endif
rc = SPWQ_ERR_RESPONSE;
}
leave:
if (errorcode)
*errorcode = rc;
if (fd != -1)
close (fd);
if (pw)
spwq_secure_free (pw);
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)
{
int fd = -1;
int nread;
char response[500];
int rc;
rc = agent_open (&fd);
if (rc)
goto leave;
rc = writen (fd, query, strlen (query));
if (rc)
goto leave;
/* get response */
nread = readline (fd, response, 499);
if (nread < 0)
{
rc = -nread;
goto leave;
}
if (nread < 3)
{
rc = SPWQ_PROTOCOL_ERROR;
goto leave;
}
if (response[0] == 'O' && response[1] == 'K')
/* OK, do nothing. */;
else if ((nread > 7 && !memcmp (response, "ERR 111", 7)
&& (response[7] == ' ' || response[7] == '\n') )
|| ((nread > 4 && !memcmp (response, "ERR ", 4)
&& (strtoul (response+4, NULL, 0) & 0xffff) == 99)) )
{
/* 111 is the old Assuan code for canceled which might still
be in use by old installations. 99 is GPG_ERR_CANCELED as
used by modern gpg-agents; 0xffff is used to mask out the
error source. */
#ifdef SPWQ_USE_LOGGING
log_info (_("canceled by user\n") );
#endif
}
else
{
#ifdef SPWQ_USE_LOGGING
log_error (_("problem with the agent\n"));
#endif
rc = SPWQ_ERR_RESPONSE;
}
leave:
if (fd != -1)
close (fd);
return rc;
}

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