/* sh-cmd.c - The Assuan server for g13-syshelp
* Copyright (C) 2015 Werner Koch
*
* 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 .
*/
#include
#include
#include
#include
#include
#include
#include
#include "g13-syshelp.h"
#include
#include "../common/i18n.h"
#include "../common/asshelp.h"
#include "keyblob.h"
/* Local data for this server module. A pointer to this is stored in
the CTRL object of each connection. */
struct server_local_s
{
/* The Assuan context we are working on. */
assuan_context_t assuan_ctx;
/* The malloced name of the device. */
char *devicename;
/* A stream open for read of the device set by the DEVICE command or
NULL if no DEVICE command has been used. */
estream_t devicefp;
};
/* Local prototypes. */
/*
Helper functions.
*/
/* Set an error and a description. */
#define set_error(e,t) assuan_set_error (ctx, gpg_error (e), (t))
#define set_error_fail_cmd() set_error (GPG_ERR_NOT_INITIALIZED, \
"not called via userv or unknown user")
/* Skip over options. Blanks after the options are also removed. */
static char *
skip_options (const char *line)
{
while (spacep (line))
line++;
while ( *line == '-' && line[1] == '-' )
{
while (*line && !spacep (line))
line++;
while (spacep (line))
line++;
}
return (char*)line;
}
/* Check whether the option NAME appears in LINE. */
static int
has_option (const char *line, const char *name)
{
const char *s;
int n = strlen (name);
s = strstr (line, name);
if (s && s >= skip_options (line))
return 0;
return (s && (s == line || spacep (s-1)) && (!s[n] || spacep (s+n)));
}
/* Helper to print a message while leaving a command. */
static gpg_error_t
leave_cmd (assuan_context_t ctx, gpg_error_t err)
{
if (err)
{
const char *name = assuan_get_command_name (ctx);
if (!name)
name = "?";
if (gpg_err_source (err) == GPG_ERR_SOURCE_DEFAULT)
log_error ("command '%s' failed: %s\n", name,
gpg_strerror (err));
else
log_error ("command '%s' failed: %s <%s>\n", name,
gpg_strerror (err), gpg_strsource (err));
}
return err;
}
/* The handler for Assuan OPTION commands. */
static gpg_error_t
option_handler (assuan_context_t ctx, const char *key, const char *value)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
(void)ctrl;
(void)key;
(void)value;
if (ctrl->fail_all_cmds)
err = set_error_fail_cmd ();
else
err = gpg_error (GPG_ERR_UNKNOWN_OPTION);
return err;
}
/* The handler for an Assuan RESET command. */
static gpg_error_t
reset_notify (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
(void)line;
xfree (ctrl->server_local->devicename);
ctrl->server_local->devicename = NULL;
es_fclose (ctrl->server_local->devicefp);
ctrl->server_local->devicefp = NULL;
ctrl->devti = NULL;
assuan_close_input_fd (ctx);
assuan_close_output_fd (ctx);
return 0;
}
static const char hlp_finddevice[] =
"FINDDEVICE \n"
"\n"
"Find the device matching NAME. NAME be any identifier from\n"
"g13tab permissible for the user. The corresponding block\n"
"device is returned using a status line.";
static gpg_error_t
cmd_finddevice (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
tab_item_t ti;
const char *s;
const char *name;
name = skip_options (line);
/* Are we allowed to use the given device? We check several names:
* 1. The full block device
* 2. The label
* 3. The final part of the block device if NAME does not have a slash.
* 4. The mountpoint
*/
for (ti=ctrl->client.tab; ti; ti = ti->next)
if (!strcmp (name, ti->blockdev))
break;
if (!ti)
{
for (ti=ctrl->client.tab; ti; ti = ti->next)
if (ti->label && !strcmp (name, ti->label))
break;
}
if (!ti && !strchr (name, '/'))
{
for (ti=ctrl->client.tab; ti; ti = ti->next)
{
s = strrchr (ti->blockdev, '/');
if (s && s[1] && !strcmp (name, s+1))
break;
}
}
if (!ti)
{
for (ti=ctrl->client.tab; ti; ti = ti->next)
if (ti->mountpoint && !strcmp (name, ti->mountpoint))
break;
}
if (!ti)
{
err = set_error (GPG_ERR_NOT_FOUND, "device not configured for user");
goto leave;
}
/* Check whether we have permissions to open the device. */
{
estream_t fp = es_fopen (ti->blockdev, "rb");
if (!fp)
{
err = gpg_error_from_syserror ();
log_error ("error opening '%s': %s\n",
ti->blockdev, gpg_strerror (err));
goto leave;
}
es_fclose (fp);
}
err = g13_status (ctrl, STATUS_BLOCKDEV, ti->blockdev, NULL);
if (err)
return err;
leave:
return leave_cmd (ctx, err);
}
static const char hlp_device[] =
"DEVICE \n"
"\n"
"Set the device used by further commands.\n"
"A device name or a PARTUUID string may be used.\n"
"Access to that device (by the g13 system) is locked\n"
"until a new DEVICE command or end of this process\n";
static gpg_error_t
cmd_device (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
tab_item_t ti;
estream_t fp = NULL;
line = skip_options (line);
/* # warning hardwired to /dev/sdb1 ! */
/* if (strcmp (line, "/dev/sdb1")) */
/* { */
/* err = gpg_error (GPG_ERR_ENOENT); */
/* goto leave; */
/* } */
/* Always close an open device stream of this session. */
xfree (ctrl->server_local->devicename);
ctrl->server_local->devicename = NULL;
es_fclose (ctrl->server_local->devicefp);
ctrl->server_local->devicefp = NULL;
/* Are we allowed to use the given device? */
for (ti=ctrl->client.tab; ti; ti = ti->next)
if (!strcmp (line, ti->blockdev))
break;
if (!ti)
{
err = set_error (GPG_ERR_EACCES, "device not configured for user");
goto leave;
}
ctrl->server_local->devicename = xtrystrdup (line);
if (!ctrl->server_local->devicename)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Check whether we have permissions to open the device and keep an
FD open. */
fp = es_fopen (ctrl->server_local->devicename, "rb");
if (!fp)
{
err = gpg_error_from_syserror ();
log_error ("error opening '%s': %s\n",
ctrl->server_local->devicename, gpg_strerror (err));
goto leave;
}
es_fclose (ctrl->server_local->devicefp);
ctrl->server_local->devicefp = fp;
fp = NULL;
ctrl->devti = ti;
/* Fixme: Take some kind of lock. */
leave:
es_fclose (fp);
if (err)
{
xfree (ctrl->server_local->devicename);
ctrl->server_local->devicename = NULL;
ctrl->devti = NULL;
}
return leave_cmd (ctx, err);
}
static const char hlp_create[] =
"CREATE \n"
"\n"
"Create a new encrypted partition on the current device.\n"
" must be \"dm-crypt\" for now.";
static gpg_error_t
cmd_create (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
estream_t fp = NULL;
line = skip_options (line);
if (strcmp (line, "dm-crypt"))
{
err = set_error (GPG_ERR_INV_ARG, "Type must be \"dm-crypt\"");
goto leave;
}
if (!ctrl->server_local->devicename
|| !ctrl->server_local->devicefp
|| !ctrl->devti)
{
err = set_error (GPG_ERR_ENOENT, "No device has been set");
goto leave;
}
err = sh_is_empty_partition (ctrl->server_local->devicename);
if (err)
{
if (gpg_err_code (err) == GPG_ERR_FALSE)
err = gpg_error (GPG_ERR_CONFLICT);
err = assuan_set_error (ctx, err, "Partition is not empty");
goto leave;
}
/* We need a writeable stream to create the container. */
fp = es_fopen (ctrl->server_local->devicename, "r+b");
if (!fp)
{
err = gpg_error_from_syserror ();
log_error ("error opening '%s': %s\n",
ctrl->server_local->devicename, gpg_strerror (err));
goto leave;
}
if (es_setvbuf (fp, NULL, _IONBF, 0))
{
err = gpg_error_from_syserror ();
log_error ("error setting '%s' to _IONBF: %s\n",
ctrl->server_local->devicename, gpg_strerror (err));
goto leave;
}
err = sh_dmcrypt_create_container (ctrl,
ctrl->server_local->devicename,
fp);
if (es_fclose (fp))
{
gpg_error_t err2 = gpg_error_from_syserror ();
log_error ("error closing '%s': %s\n",
ctrl->server_local->devicename, gpg_strerror (err2));
if (!err)
err = err2;
}
fp = NULL;
leave:
es_fclose (fp);
return leave_cmd (ctx, err);
}
static const char hlp_getkeyblob[] =
"GETKEYBLOB\n"
"\n"
"Return the encrypted keyblob of the current device.";
static gpg_error_t
cmd_getkeyblob (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err;
void *enckeyblob = NULL;
size_t enckeybloblen;
line = skip_options (line);
if (!ctrl->server_local->devicename
|| !ctrl->server_local->devicefp
|| !ctrl->devti)
{
err = set_error (GPG_ERR_ENOENT, "No device has been set");
goto leave;
}
err = sh_is_empty_partition (ctrl->server_local->devicename);
if (!err)
{
err = gpg_error (GPG_ERR_ENODEV);
assuan_set_error (ctx, err, "Partition is empty");
goto leave;
}
err = 0;
err = g13_keyblob_read (ctrl->server_local->devicename,
&enckeyblob, &enckeybloblen);
if (err)
goto leave;
err = assuan_send_data (ctx, enckeyblob, enckeybloblen);
if (!err)
err = assuan_send_data (ctx, NULL, 0); /* Flush */
leave:
xfree (enckeyblob);
return leave_cmd (ctx, err);
}
static const char hlp_mount[] =
"MOUNT [--no-mount] \n"
"\n"
"Mount an encrypted partition on the current device.\n"
" must be \"dm-crypt\" for now. Option --no-mount\n"
"stops right before calling the mount command.\n";
static gpg_error_t
cmd_mount (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
unsigned char *keyblob = NULL;
size_t keybloblen;
tupledesc_t tuples = NULL;
int nomount;
nomount = has_option (line, "--no-mount");
line = skip_options (line);
if (strcmp (line, "dm-crypt"))
{
err = set_error (GPG_ERR_INV_ARG, "Type must be \"dm-crypt\"");
goto leave;
}
if (!ctrl->server_local->devicename
|| !ctrl->server_local->devicefp
|| !ctrl->devti)
{
err = set_error (GPG_ERR_ENOENT, "No device has been set");
goto leave;
}
err = sh_is_empty_partition (ctrl->server_local->devicename);
if (!err)
{
err = gpg_error (GPG_ERR_ENODEV);
assuan_set_error (ctx, err, "Partition is empty");
goto leave;
}
err = 0;
/* We expect that the client already decrypted the keyblob.
* Eventually we should move reading of the keyblob to here and ask
* the client to decrypt it. */
assuan_begin_confidential (ctx);
err = assuan_inquire (ctx, "KEYBLOB",
&keyblob, &keybloblen, 4 * 1024);
assuan_end_confidential (ctx);
if (err)
{
log_error (_("assuan_inquire failed: %s\n"), gpg_strerror (err));
goto leave;
}
err = create_tupledesc (&tuples, keyblob, keybloblen);
if (!err)
keyblob = NULL;
else
{
if (gpg_err_code (err) == GPG_ERR_NOT_SUPPORTED)
log_error ("unknown keyblob version received\n");
goto leave;
}
err = sh_dmcrypt_mount_container (ctrl,
ctrl->server_local->devicename,
tuples, nomount);
leave:
destroy_tupledesc (tuples);
return leave_cmd (ctx, err);
}
static const char hlp_umount[] =
"UMOUNT \n"
"\n"
"Unmount an encrypted partition and wipe the key.\n"
" must be \"dm-crypt\" for now.";
static gpg_error_t
cmd_umount (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
line = skip_options (line);
if (strcmp (line, "dm-crypt"))
{
err = set_error (GPG_ERR_INV_ARG, "Type must be \"dm-crypt\"");
goto leave;
}
if (!ctrl->server_local->devicename
|| !ctrl->server_local->devicefp
|| !ctrl->devti)
{
err = set_error (GPG_ERR_ENOENT, "No device has been set");
goto leave;
}
err = sh_dmcrypt_umount_container (ctrl, ctrl->server_local->devicename);
leave:
return leave_cmd (ctx, err);
}
static const char hlp_suspend[] =
"SUSPEND \n"
"\n"
"Suspend an encrypted partition and wipe the key.\n"
" must be \"dm-crypt\" for now.";
static gpg_error_t
cmd_suspend (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
line = skip_options (line);
if (strcmp (line, "dm-crypt"))
{
err = set_error (GPG_ERR_INV_ARG, "Type must be \"dm-crypt\"");
goto leave;
}
if (!ctrl->server_local->devicename
|| !ctrl->server_local->devicefp
|| !ctrl->devti)
{
err = set_error (GPG_ERR_ENOENT, "No device has been set");
goto leave;
}
err = sh_is_empty_partition (ctrl->server_local->devicename);
if (!err)
{
err = gpg_error (GPG_ERR_ENODEV);
assuan_set_error (ctx, err, "Partition is empty");
goto leave;
}
err = 0;
err = sh_dmcrypt_suspend_container (ctrl, ctrl->server_local->devicename);
leave:
return leave_cmd (ctx, err);
}
static const char hlp_resume[] =
"RESUME \n"
"\n"
"Resume an encrypted partition and set the key.\n"
" must be \"dm-crypt\" for now.";
static gpg_error_t
cmd_resume (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
unsigned char *keyblob = NULL;
size_t keybloblen;
tupledesc_t tuples = NULL;
line = skip_options (line);
if (strcmp (line, "dm-crypt"))
{
err = set_error (GPG_ERR_INV_ARG, "Type must be \"dm-crypt\"");
goto leave;
}
if (!ctrl->server_local->devicename
|| !ctrl->server_local->devicefp
|| !ctrl->devti)
{
err = set_error (GPG_ERR_ENOENT, "No device has been set");
goto leave;
}
err = sh_is_empty_partition (ctrl->server_local->devicename);
if (!err)
{
err = gpg_error (GPG_ERR_ENODEV);
assuan_set_error (ctx, err, "Partition is empty");
goto leave;
}
err = 0;
/* We expect that the client already decrypted the keyblob.
* Eventually we should move reading of the keyblob to here and ask
* the client to decrypt it. */
assuan_begin_confidential (ctx);
err = assuan_inquire (ctx, "KEYBLOB",
&keyblob, &keybloblen, 4 * 1024);
assuan_end_confidential (ctx);
if (err)
{
log_error (_("assuan_inquire failed: %s\n"), gpg_strerror (err));
goto leave;
}
err = create_tupledesc (&tuples, keyblob, keybloblen);
if (!err)
keyblob = NULL;
else
{
if (gpg_err_code (err) == GPG_ERR_NOT_SUPPORTED)
log_error ("unknown keyblob version received\n");
goto leave;
}
err = sh_dmcrypt_resume_container (ctrl,
ctrl->server_local->devicename,
tuples);
leave:
destroy_tupledesc (tuples);
return leave_cmd (ctx, err);
}
static const char hlp_getinfo[] =
"GETINFO \n"
"\n"
"Multipurpose function to return a variety of information.\n"
"Supported values for WHAT are:\n"
"\n"
" version - Return the version of the program.\n"
" pid - Return the process id of the server.\n"
" showtab - Show the table for the user.";
static gpg_error_t
cmd_getinfo (assuan_context_t ctx, char *line)
{
ctrl_t ctrl = assuan_get_pointer (ctx);
gpg_error_t err = 0;
char *buf;
if (!strcmp (line, "version"))
{
const char *s = PACKAGE_VERSION;
err = assuan_send_data (ctx, s, strlen (s));
}
else if (!strcmp (line, "pid"))
{
char numbuf[50];
snprintf (numbuf, sizeof numbuf, "%lu", (unsigned long)getpid ());
err = assuan_send_data (ctx, numbuf, strlen (numbuf));
}
else if (!strncmp (line, "getsz", 5))
{
unsigned long long nblocks;
err = sh_blockdev_getsz (line+6, &nblocks);
if (!err)
log_debug ("getsz=%llu\n", nblocks);
}
else if (!strcmp (line, "showtab"))
{
tab_item_t ti;
for (ti=ctrl->client.tab; !err && ti; ti = ti->next)
{
buf = es_bsprintf ("%s %s%s %s %s%s\n",
ctrl->client.uname,
*ti->blockdev=='/'? "":"partuuid=",
ti->blockdev,
ti->label? ti->label : "-",
ti->mountpoint? " ":"",
ti->mountpoint? ti->mountpoint:"");
if (!buf)
err = gpg_error_from_syserror ();
else
{
err = assuan_send_data (ctx, buf, strlen (buf));
if (!err)
err = assuan_send_data (ctx, NULL, 0); /* Flush */
}
xfree (buf);
}
}
else
err = set_error (GPG_ERR_ASS_PARAMETER, "unknown value for WHAT");
return leave_cmd (ctx, err);
}
/* This command handler is used for all commands if this process has
not been started as expected. */
static gpg_error_t
fail_command (assuan_context_t ctx, char *line)
{
gpg_error_t err;
const char *name = assuan_get_command_name (ctx);
(void)line;
if (!name)
name = "?";
err = set_error_fail_cmd ();
log_error ("command '%s' failed: %s\n", name, gpg_strerror (err));
return err;
}
/* Tell the Assuan library about our commands. */
static int
register_commands (assuan_context_t ctx, int fail_all)
{
static struct {
const char *name;
assuan_handler_t handler;
const char * const help;
} table[] = {
{ "FINDDEVICE", cmd_finddevice, hlp_finddevice },
{ "DEVICE", cmd_device, hlp_device },
{ "CREATE", cmd_create, hlp_create },
{ "GETKEYBLOB", cmd_getkeyblob, hlp_getkeyblob },
{ "MOUNT", cmd_mount, hlp_mount },
{ "UMOUNT", cmd_umount, hlp_umount },
{ "SUSPEND", cmd_suspend,hlp_suspend},
{ "RESUME", cmd_resume, hlp_resume },
{ "INPUT", NULL },
{ "OUTPUT", NULL },
{ "GETINFO", cmd_getinfo, hlp_getinfo },
{ NULL }
};
gpg_error_t err;
int i;
for (i=0; table[i].name; i++)
{
err = assuan_register_command (ctx, table[i].name,
fail_all ? fail_command : table[i].handler,
table[i].help);
if (err)
return err;
}
return 0;
}
/* Startup the server. */
gpg_error_t
syshelp_server (ctrl_t ctrl)
{
gpg_error_t err;
assuan_fd_t filedes[2];
assuan_context_t ctx = NULL;
/* We use a pipe based server so that we can work from scripts.
assuan_init_pipe_server will automagically detect when we are
called with a socketpair and ignore FILEDES in this case. */
filedes[0] = assuan_fdopen (0);
filedes[1] = assuan_fdopen (1);
err = assuan_new (&ctx);
if (err)
{
log_error ("failed to allocate an Assuan context: %s\n",
gpg_strerror (err));
goto leave;
}
err = assuan_init_pipe_server (ctx, filedes);
if (err)
{
log_error ("failed to initialize the server: %s\n", gpg_strerror (err));
goto leave;
}
err = register_commands (ctx, 0 /*FIXME:ctrl->fail_all_cmds*/);
if (err)
{
log_error ("failed to the register commands with Assuan: %s\n",
gpg_strerror (err));
goto leave;
}
assuan_set_pointer (ctx, ctrl);
{
char *tmp = xtryasprintf ("G13-syshelp %s ready to serve requests "
"from %lu(%s)",
PACKAGE_VERSION,
(unsigned long)ctrl->client.uid,
ctrl->client.uname);
if (tmp)
{
assuan_set_hello_line (ctx, tmp);
xfree (tmp);
}
}
assuan_register_reset_notify (ctx, reset_notify);
assuan_register_option_handler (ctx, option_handler);
ctrl->server_local = xtrycalloc (1, sizeof *ctrl->server_local);
if (!ctrl->server_local)
{
err = gpg_error_from_syserror ();
goto leave;
}
ctrl->server_local->assuan_ctx = ctx;
while ( !(err = assuan_accept (ctx)) )
{
err = assuan_process (ctx);
if (err)
log_info ("Assuan processing failed: %s\n", gpg_strerror (err));
}
if (err == -1)
err = 0;
else
log_info ("Assuan accept problem: %s\n", gpg_strerror (err));
leave:
reset_notify (ctx, NULL); /* Release all items hold by SERVER_LOCAL. */
if (ctrl->server_local)
{
xfree (ctrl->server_local);
ctrl->server_local = NULL;
}
assuan_release (ctx);
return err;
}
gpg_error_t
sh_encrypt_keyblob (ctrl_t ctrl, const void *keyblob, size_t keybloblen,
char **r_enckeyblob, size_t *r_enckeybloblen)
{
assuan_context_t ctx = ctrl->server_local->assuan_ctx;
gpg_error_t err;
unsigned char *enckeyblob;
size_t enckeybloblen;
*r_enckeyblob = NULL;
/* Send the plaintext. */
err = g13_status (ctrl, STATUS_PLAINTEXT_FOLLOWS, NULL);
if (err)
return err;
assuan_begin_confidential (ctx);
err = assuan_send_data (ctx, keyblob, keybloblen);
if (!err)
err = assuan_send_data (ctx, NULL, 0);
assuan_end_confidential (ctx);
if (!err)
err = assuan_write_line (ctx, "END");
if (err)
{
log_error (_("error sending data: %s\n"), gpg_strerror (err));
return err;
}
/* Inquire the ciphertext. */
err = assuan_inquire (ctx, "ENCKEYBLOB",
&enckeyblob, &enckeybloblen, 16 * 1024);
if (err)
{
log_error (_("assuan_inquire failed: %s\n"), gpg_strerror (err));
return err;
}
*r_enckeyblob = enckeyblob;
*r_enckeybloblen = enckeybloblen;
return 0;
}
/* Send a status line with status ID NO. The arguments are a list of
strings terminated by a NULL argument. */
gpg_error_t
g13_status (ctrl_t ctrl, int no, ...)
{
gpg_error_t err;
va_list arg_ptr;
va_start (arg_ptr, no);
err = vprint_assuan_status_strings (ctrl->server_local->assuan_ctx,
get_status_string (no), arg_ptr);
va_end (arg_ptr);
return err;
}