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glib/gio/gdbusauthmechanismsha1.c
Philip Withnall dc0eb5e49a gdbusauthmechanismsha1: Don’t delete a stale lock file if it’s changed 
The retry loop for acquiring the lock for the authentication cookie file
currently tries to acquire the lock for 0.5s, then gives up, assumes the
lock file is stale, and deletes it.

That’s great if the lock file *is* stale because it’s been left there by
a crashed process.

It’s not so great if the lock file just happens to have been there every
time this process checked, because the cookie file is highly contested
while (for example) running lots of parallel unit tests.

Check for that situation by comparing the mtime of the lock file and
continuing to retry if it’s changed.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>

Fixes: #1929
2022-02-18 13:17:19 +00:00

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/* GDBus - GLib D-Bus Library
*
* Copyright (C) 2008-2010 Red Hat, Inc.
*
* This library 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.
*
* This library 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 library; if not, see <http://www.gnu.org/licenses/>.
*
* Author: David Zeuthen <davidz@redhat.com>
*/
#include "config.h"
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <glib/gstdio.h>
#ifdef G_OS_UNIX
#include <unistd.h>
#endif
#ifdef G_OS_WIN32
#include <io.h>
#include "gwin32sid.h"
#endif
#include "gdbusauthmechanismsha1.h"
#include "gcredentials.h"
#include "gdbuserror.h"
#include "glocalfileinfo.h"
#include "gioenumtypes.h"
#include "gioerror.h"
#include "gdbusprivate.h"
#include "glib-private.h"
#include "glibintl.h"
/*
* Arbitrary timeouts for keys in the keyring.
* For interoperability, these match the reference implementation, libdbus.
* To make them easier to compare, their names also match libdbus
* (see dbus/dbus-keyring.c).
*/
/*
* Maximum age of a key before we create a new key to use in challenges:
* 5 minutes.
*/
#define NEW_KEY_TIMEOUT_SECONDS (60*5)
/*
* Time before we drop a key from the keyring: 7 minutes.
* Authentication will succeed if it takes less than
* EXPIRE_KEYS_TIMEOUT_SECONDS - NEW_KEY_TIMEOUT_SECONDS (2 minutes)
* to complete.
* The spec says "delete any cookies that are old (the timeout can be
* fairly short)".
*/
#define EXPIRE_KEYS_TIMEOUT_SECONDS (NEW_KEY_TIMEOUT_SECONDS + (60*2))
/*
* Maximum amount of time a key can be in the future due to clock skew
* with a shared home directory: 5 minutes.
* The spec says "a reasonable time in the future".
*/
#define MAX_TIME_TRAVEL_SECONDS (60*5)
struct _GDBusAuthMechanismSha1Private
{
gboolean is_client;
gboolean is_server;
GDBusAuthMechanismState state;
gchar *reject_reason; /* non-NULL iff (state == G_DBUS_AUTH_MECHANISM_STATE_REJECTED) */
/* used on the client side */
gchar *to_send;
/* used on the server side */
gchar *cookie;
gchar *server_challenge;
};
static gint mechanism_get_priority (void);
static const gchar *mechanism_get_name (void);
static gboolean mechanism_is_supported (GDBusAuthMechanism *mechanism);
static gchar *mechanism_encode_data (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len,
gsize *out_data_len);
static gchar *mechanism_decode_data (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len,
gsize *out_data_len);
static GDBusAuthMechanismState mechanism_server_get_state (GDBusAuthMechanism *mechanism);
static void mechanism_server_initiate (GDBusAuthMechanism *mechanism,
const gchar *initial_response,
gsize initial_response_len);
static void mechanism_server_data_receive (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len);
static gchar *mechanism_server_data_send (GDBusAuthMechanism *mechanism,
gsize *out_data_len);
static gchar *mechanism_server_get_reject_reason (GDBusAuthMechanism *mechanism);
static void mechanism_server_shutdown (GDBusAuthMechanism *mechanism);
static GDBusAuthMechanismState mechanism_client_get_state (GDBusAuthMechanism *mechanism);
static gchar *mechanism_client_initiate (GDBusAuthMechanism *mechanism,
gsize *out_initial_response_len);
static void mechanism_client_data_receive (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len);
static gchar *mechanism_client_data_send (GDBusAuthMechanism *mechanism,
gsize *out_data_len);
static void mechanism_client_shutdown (GDBusAuthMechanism *mechanism);
/* ---------------------------------------------------------------------------------------------------- */
G_DEFINE_TYPE_WITH_PRIVATE (GDBusAuthMechanismSha1, _g_dbus_auth_mechanism_sha1, G_TYPE_DBUS_AUTH_MECHANISM)
/* ---------------------------------------------------------------------------------------------------- */
static void
_g_dbus_auth_mechanism_sha1_finalize (GObject *object)
{
GDBusAuthMechanismSha1 *mechanism = G_DBUS_AUTH_MECHANISM_SHA1 (object);
g_free (mechanism->priv->reject_reason);
g_free (mechanism->priv->to_send);
g_free (mechanism->priv->cookie);
g_free (mechanism->priv->server_challenge);
if (G_OBJECT_CLASS (_g_dbus_auth_mechanism_sha1_parent_class)->finalize != NULL)
G_OBJECT_CLASS (_g_dbus_auth_mechanism_sha1_parent_class)->finalize (object);
}
static void
_g_dbus_auth_mechanism_sha1_class_init (GDBusAuthMechanismSha1Class *klass)
{
GObjectClass *gobject_class;
GDBusAuthMechanismClass *mechanism_class;
gobject_class = G_OBJECT_CLASS (klass);
gobject_class->finalize = _g_dbus_auth_mechanism_sha1_finalize;
mechanism_class = G_DBUS_AUTH_MECHANISM_CLASS (klass);
mechanism_class->get_priority = mechanism_get_priority;
mechanism_class->get_name = mechanism_get_name;
mechanism_class->is_supported = mechanism_is_supported;
mechanism_class->encode_data = mechanism_encode_data;
mechanism_class->decode_data = mechanism_decode_data;
mechanism_class->server_get_state = mechanism_server_get_state;
mechanism_class->server_initiate = mechanism_server_initiate;
mechanism_class->server_data_receive = mechanism_server_data_receive;
mechanism_class->server_data_send = mechanism_server_data_send;
mechanism_class->server_get_reject_reason = mechanism_server_get_reject_reason;
mechanism_class->server_shutdown = mechanism_server_shutdown;
mechanism_class->client_get_state = mechanism_client_get_state;
mechanism_class->client_initiate = mechanism_client_initiate;
mechanism_class->client_data_receive = mechanism_client_data_receive;
mechanism_class->client_data_send = mechanism_client_data_send;
mechanism_class->client_shutdown = mechanism_client_shutdown;
}
static void
_g_dbus_auth_mechanism_sha1_init (GDBusAuthMechanismSha1 *mechanism)
{
mechanism->priv = _g_dbus_auth_mechanism_sha1_get_instance_private (mechanism);
}
/* ---------------------------------------------------------------------------------------------------- */
static gint
mechanism_get_priority (void)
{
return 0;
}
static const gchar *
mechanism_get_name (void)
{
return "DBUS_COOKIE_SHA1";
}
static gboolean
mechanism_is_supported (GDBusAuthMechanism *mechanism)
{
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), FALSE);
return TRUE;
}
static gchar *
mechanism_encode_data (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len,
gsize *out_data_len)
{
return NULL;
}
static gchar *
mechanism_decode_data (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len,
gsize *out_data_len)
{
return NULL;
}
/* ---------------------------------------------------------------------------------------------------- */
static gint
random_ascii (void)
{
gint ret;
ret = g_random_int_range (0, 60);
if (ret < 25)
ret += 'A';
else if (ret < 50)
ret += 'a' - 25;
else
ret += '0' - 50;
return ret;
}
static gchar *
random_ascii_string (guint len)
{
GString *challenge;
guint n;
challenge = g_string_new (NULL);
for (n = 0; n < len; n++)
g_string_append_c (challenge, random_ascii ());
return g_string_free (challenge, FALSE);
}
static gchar *
random_blob (guint len)
{
GString *challenge;
guint n;
challenge = g_string_new (NULL);
for (n = 0; n < len; n++)
g_string_append_c (challenge, g_random_int_range (0, 256));
return g_string_free (challenge, FALSE);
}
/* ---------------------------------------------------------------------------------------------------- */
/* ensure keyring dir exists and permissions are correct */
static gchar *
ensure_keyring_directory (GError **error)
{
gchar *path;
const gchar *e;
gboolean is_setuid;
#ifdef G_OS_UNIX
struct stat statbuf;
#endif
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
e = g_getenv ("G_DBUS_COOKIE_SHA1_KEYRING_DIR");
if (e != NULL)
{
path = g_strdup (e);
}
else
{
path = g_build_filename (g_get_home_dir (),
".dbus-keyrings",
NULL);
}
#ifdef G_OS_UNIX
if (stat (path, &statbuf) != 0)
{
int errsv = errno;
if (errsv != ENOENT)
{
g_set_error (error,
G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error when getting information for directory “%s”: %s"),
path,
g_strerror (errsv));
g_clear_pointer (&path, g_free);
return NULL;
}
}
else if (S_ISDIR (statbuf.st_mode))
{
if (g_getenv ("G_DBUS_COOKIE_SHA1_KEYRING_DIR_IGNORE_PERMISSION") == NULL &&
(statbuf.st_mode & 0777) != 0700)
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("Permissions on directory “%s” are malformed. Expected mode 0700, got 0%o"),
path,
(guint) (statbuf.st_mode & 0777));
g_clear_pointer (&path, g_free);
return NULL;
}
return g_steal_pointer (&path);
}
#else /* if !G_OS_UNIX */
/* On non-Unix platforms, check that it exists as a directory, but don’t do
* permissions checks at the moment. */
if (g_file_test (path, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR))
{
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic warning "-Wcpp"
#warning Please implement permission checking on this non-UNIX platform
#pragma GCC diagnostic pop
#endif /* __GNUC__ */
return g_steal_pointer (&path);
}
#endif /* if !G_OS_UNIX */
/* Only create the directory if not running as setuid */
is_setuid = GLIB_PRIVATE_CALL (g_check_setuid) ();
if (!is_setuid &&
g_mkdir_with_parents (path, 0700) != 0)
{
int errsv = errno;
g_set_error (error,
G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error creating directory “%s”: %s"),
path,
g_strerror (errsv));
g_clear_pointer (&path, g_free);
return NULL;
}
else if (is_setuid)
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_PERMISSION_DENIED,
_("Error creating directory “%s”: %s"),
path,
_("Operation not supported"));
g_clear_pointer (&path, g_free);
return NULL;
}
return g_steal_pointer (&path);
}
/* ---------------------------------------------------------------------------------------------------- */
/* looks up an entry in the keyring */
static gchar *
keyring_lookup_entry (const gchar *cookie_context,
gint cookie_id,
GError **error)
{
gchar *ret;
gchar *keyring_dir;
gchar *contents;
gchar *path;
guint n;
gchar **lines;
g_return_val_if_fail (cookie_context != NULL, NULL);
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
ret = NULL;
path = NULL;
contents = NULL;
lines = NULL;
keyring_dir = ensure_keyring_directory (error);
if (keyring_dir == NULL)
goto out;
path = g_build_filename (keyring_dir, cookie_context, NULL);
if (!g_file_get_contents (path,
&contents,
NULL,
error))
{
g_prefix_error (error,
_("Error opening keyring “%s” for reading: "),
path);
goto out;
}
g_assert (contents != NULL);
lines = g_strsplit (contents, "\n", 0);
for (n = 0; lines[n] != NULL; n++)
{
const gchar *line = lines[n];
gchar **tokens;
gchar *endp;
gint line_id;
if (line[0] == '\0')
continue;
tokens = g_strsplit (line, " ", 0);
if (g_strv_length (tokens) != 3)
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("Line %d of the keyring at “%s” with content “%s” is malformed"),
n + 1,
path,
line);
g_strfreev (tokens);
goto out;
}
line_id = g_ascii_strtoll (tokens[0], &endp, 10);
if (*endp != '\0')
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("First token of line %d of the keyring at “%s” with content “%s” is malformed"),
n + 1,
path,
line);
g_strfreev (tokens);
goto out;
}
(void)g_ascii_strtoll (tokens[1], &endp, 10); /* do not care what the timestamp is */
if (*endp != '\0')
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("Second token of line %d of the keyring at “%s” with content “%s” is malformed"),
n + 1,
path,
line);
g_strfreev (tokens);
goto out;
}
if (line_id == cookie_id)
{
/* YAY, success */
ret = tokens[2]; /* steal pointer */
tokens[2] = NULL;
g_strfreev (tokens);
goto out;
}
g_strfreev (tokens);
}
/* BOOH, didn't find the cookie */
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("Didn’t find cookie with id %d in the keyring at “%s”"),
cookie_id,
path);
out:
g_free (keyring_dir);
g_free (path);
g_free (contents);
g_strfreev (lines);
return ret;
}
/* function for logging important events that the system administrator should take notice of */
G_GNUC_PRINTF(1, 2)
static void
_log (const gchar *message,
...)
{
gchar *s;
va_list var_args;
va_start (var_args, message);
s = g_strdup_vprintf (message, var_args);
va_end (var_args);
/* TODO: might want to send this to syslog instead */
g_printerr ("GDBus-DBUS_COOKIE_SHA1: %s\n", s);
g_free (s);
}
/* Returns FD for lock file, if it was created exclusively (didn't exist already,
* and was created successfully) */
static gint
create_lock_exclusive (const gchar *lock_path,
gint64 *mtime_nsec,
GError **error)
{
int errsv;
gint ret;
ret = g_open (lock_path, O_CREAT | O_EXCL, 0600);
errsv = errno;
if (ret < 0)
{
GLocalFileStat stat_buf;
/* Get the modification time to distinguish between the lock being stale
* or highly contested. */
if (mtime_nsec != NULL &&
g_local_file_stat (lock_path, G_LOCAL_FILE_STAT_FIELD_MTIME, G_LOCAL_FILE_STAT_FIELD_ALL, &stat_buf) == 0)
*mtime_nsec = _g_stat_mtime (&stat_buf) * G_USEC_PER_SEC * 1000 + _g_stat_mtim_nsec (&stat_buf);
else if (mtime_nsec != NULL)
*mtime_nsec = 0;
g_set_error (error,
G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error creating lock file “%s”: %s"),
lock_path,
g_strerror (errsv));
return -1;
}
return ret;
}
static gint
keyring_acquire_lock (const gchar *path,
GError **error)
{
gchar *lock = NULL;
gint ret;
guint num_tries;
int errsv;
gint64 lock_mtime_nsec = 0, lock_mtime_nsec_prev = 0;
/* Total possible sleep period = max_tries * timeout_usec = 0.5s */
const guint max_tries = 50;
const guint timeout_usec = 1000 * 10;
g_return_val_if_fail (path != NULL, -1);
g_return_val_if_fail (error == NULL || *error == NULL, -1);
ret = -1;
lock = g_strconcat (path, ".lock", NULL);
/* This is what the D-Bus spec says
* (https://dbus.freedesktop.org/doc/dbus-specification.html#auth-mechanisms-sha)
*
* Create a lockfile name by appending ".lock" to the name of the
* cookie file. The server should attempt to create this file using
* O_CREAT | O_EXCL. If file creation fails, the lock
* fails. Servers should retry for a reasonable period of time,
* then they may choose to delete an existing lock to keep users
* from having to manually delete a stale lock. [1]
*
* [1] : Lockfiles are used instead of real file locking fcntl() because
* real locking implementations are still flaky on network filesystems
*/
for (num_tries = 0; num_tries < max_tries; num_tries++)
{
lock_mtime_nsec_prev = lock_mtime_nsec;
/* Ignore the error until the final call. */
ret = create_lock_exclusive (lock, &lock_mtime_nsec, NULL);
if (ret >= 0)
break;
/* sleep 10ms, then try again */
g_usleep (timeout_usec);
/* If the mtime of the lock file changed, don’t count the retry, as it
* seems like there’s contention between processes for the lock file,
* rather than a stale lock file from a crashed process. */
if (num_tries > 0 && lock_mtime_nsec != lock_mtime_nsec_prev)
num_tries--;
}
if (num_tries == max_tries)
{
/* ok, we slept 50*10ms = 0.5 seconds. Conclude that the lock file must be
* stale (nuke it from orbit)
*/
if (g_unlink (lock) != 0)
{
errsv = errno;
g_set_error (error,
G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error deleting stale lock file “%s”: %s"),
lock,
g_strerror (errsv));
goto out;
}
_log ("Deleted stale lock file '%s'", lock);
/* Try one last time to create it, now that we've deleted the stale one */
ret = create_lock_exclusive (lock, NULL, error);
if (ret < 0)
goto out;
}
out:
g_free (lock);
return ret;
}
static gboolean
keyring_release_lock (const gchar *path,
gint lock_fd,
GError **error)
{
gchar *lock;
gboolean ret;
g_return_val_if_fail (path != NULL, FALSE);
g_return_val_if_fail (lock_fd != -1, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
ret = FALSE;
lock = g_strdup_printf ("%s.lock", path);
if (close (lock_fd) != 0)
{
int errsv = errno;
g_set_error (error,
G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error closing (unlinked) lock file “%s”: %s"),
lock,
g_strerror (errsv));
goto out;
}
if (g_unlink (lock) != 0)
{
int errsv = errno;
g_set_error (error,
G_IO_ERROR,
g_io_error_from_errno (errsv),
_("Error unlinking lock file “%s”: %s"),
lock,
g_strerror (errsv));
goto out;
}
ret = TRUE;
out:
g_free (lock);
return ret;
}
/* adds an entry to the keyring, taking care of locking and deleting stale/future entries */
static gboolean
keyring_generate_entry (const gchar *cookie_context,
gint *out_id,
gchar **out_cookie,
GError **error)
{
gboolean ret;
gchar *keyring_dir;
gchar *path;
gchar *contents;
GError *local_error;
gchar **lines;
gint max_line_id;
GString *new_contents;
gint64 now;
gboolean have_id;
gint use_id;
gchar *use_cookie;
gboolean changed_file;
gint lock_fd;
g_return_val_if_fail (cookie_context != NULL, FALSE);
g_return_val_if_fail (out_id != NULL, FALSE);
g_return_val_if_fail (out_cookie != NULL, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
ret = FALSE;
path = NULL;
contents = NULL;
lines = NULL;
new_contents = NULL;
have_id = FALSE;
use_id = 0;
use_cookie = NULL;
lock_fd = -1;
keyring_dir = ensure_keyring_directory (error);
if (keyring_dir == NULL)
goto out;
path = g_build_filename (keyring_dir, cookie_context, NULL);
lock_fd = keyring_acquire_lock (path, error);
if (lock_fd == -1)
goto out;
local_error = NULL;
contents = NULL;
if (!g_file_get_contents (path,
&contents,
NULL,
&local_error))
{
if (local_error->domain == G_FILE_ERROR && local_error->code == G_FILE_ERROR_NOENT)
{
/* file doesn't have to exist */
g_error_free (local_error);
}
else
{
g_propagate_prefixed_error (error,
local_error,
_("Error opening keyring “%s” for writing: "),
path);
goto out;
}
}
new_contents = g_string_new (NULL);
now = g_get_real_time () / G_USEC_PER_SEC;
changed_file = FALSE;
max_line_id = 0;
if (contents != NULL)
{
guint n;
lines = g_strsplit (contents, "\n", 0);
for (n = 0; lines[n] != NULL; n++)
{
const gchar *line = lines[n];
gchar **tokens;
gchar *endp;
gint line_id;
gint64 line_when;
gboolean keep_entry;
if (line[0] == '\0')
continue;
tokens = g_strsplit (line, " ", 0);
if (g_strv_length (tokens) != 3)
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("Line %d of the keyring at “%s” with content “%s” is malformed"),
n + 1,
path,
line);
g_strfreev (tokens);
goto out;
}
line_id = g_ascii_strtoll (tokens[0], &endp, 10);
if (*endp != '\0')
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("First token of line %d of the keyring at “%s” with content “%s” is malformed"),
n + 1,
path,
line);
g_strfreev (tokens);
goto out;
}
line_when = g_ascii_strtoll (tokens[1], &endp, 10);
if (*endp != '\0')
{
g_set_error (error,
G_IO_ERROR,
G_IO_ERROR_FAILED,
_("Second token of line %d of the keyring at “%s” with content “%s” is malformed"),
n + 1,
path,
line);
g_strfreev (tokens);
goto out;
}
/* D-Bus spec says:
*
* Once the lockfile has been created, the server loads the
* cookie file. It should then delete any cookies that are
* old (the timeout can be fairly short), or more than a
* reasonable time in the future (so that cookies never
* accidentally become permanent, if the clock was set far
* into the future at some point). If no recent keys remain,
* the server may generate a new key.
*
*/
keep_entry = TRUE;
if (line_when > now)
{
/* Oddball case: entry is more recent than our current wall-clock time..
* This is OK, it means that another server on another machine but with
* same $HOME wrote the entry. */
if (line_when - now > MAX_TIME_TRAVEL_SECONDS)
{
keep_entry = FALSE;
_log ("Deleted SHA1 cookie from %" G_GUINT64_FORMAT " seconds in the future", line_when - now);
}
}
else
{
/* Discard entry if it's too old. */
if (now - line_when > EXPIRE_KEYS_TIMEOUT_SECONDS)
{
keep_entry = FALSE;
}
}
if (!keep_entry)
{
changed_file = FALSE;
}
else
{
g_string_append_printf (new_contents,
"%d %" G_GUINT64_FORMAT " %s\n",
line_id,
line_when,
tokens[2]);
max_line_id = MAX (line_id, max_line_id);
/* Only reuse entry if not older than 5 minutes.
*
* (We need a bit of grace time compared to 7 minutes above.. otherwise
* there's a race where we reuse the 6min59.9 secs old entry and a
* split-second later another server purges the now 7 minute old entry.)
*/
if (now - line_when < NEW_KEY_TIMEOUT_SECONDS)
{
if (!have_id)
{
use_id = line_id;
use_cookie = tokens[2]; /* steal memory */
tokens[2] = NULL;
have_id = TRUE;
}
}
}
g_strfreev (tokens);
}
} /* for each line */
ret = TRUE;
if (have_id)
{
*out_id = use_id;
*out_cookie = use_cookie;
use_cookie = NULL;
}
else
{
gchar *raw_cookie;
*out_id = max_line_id + 1;
raw_cookie = random_blob (32);
*out_cookie = _g_dbus_hexencode (raw_cookie, 32);
g_free (raw_cookie);
g_string_append_printf (new_contents,
"%d %" G_GINT64_FORMAT " %s\n",
*out_id,
g_get_real_time () / G_USEC_PER_SEC,
*out_cookie);
changed_file = TRUE;
}
/* and now actually write the cookie file if there are changes (this is atomic) */
if (changed_file)
{
if (!g_file_set_contents_full (path,
new_contents->str,
-1,
G_FILE_SET_CONTENTS_CONSISTENT,
0600,
error))
{
*out_id = 0;
g_free (*out_cookie);
*out_cookie = 0;
ret = FALSE;
goto out;
}
}
out:
if (lock_fd != -1)
{
GError *local_error;
local_error = NULL;
if (!keyring_release_lock (path, lock_fd, &local_error))
{
if (error != NULL)
{
if (*error == NULL)
{
*error = local_error;
}
else
{
g_prefix_error (error,
_("(Additionally, releasing the lock for “%s” also failed: %s) "),
path,
local_error->message);
g_error_free (local_error);
}
}
else
{
g_error_free (local_error);
}
}
}
g_free (keyring_dir);
g_free (path);
g_strfreev (lines);
g_free (contents);
if (new_contents != NULL)
g_string_free (new_contents, TRUE);
g_free (use_cookie);
return ret;
}
/* ---------------------------------------------------------------------------------------------------- */
static gchar *
generate_sha1 (const gchar *server_challenge,
const gchar *client_challenge,
const gchar *cookie)
{
GString *str;
gchar *sha1;
str = g_string_new (server_challenge);
g_string_append_c (str, ':');
g_string_append (str, client_challenge);
g_string_append_c (str, ':');
g_string_append (str, cookie);
sha1 = g_compute_checksum_for_string (G_CHECKSUM_SHA1, str->str, -1);
g_string_free (str, TRUE);
return sha1;
}
/* ---------------------------------------------------------------------------------------------------- */
static GDBusAuthMechanismState
mechanism_server_get_state (GDBusAuthMechanism *mechanism)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), G_DBUS_AUTH_MECHANISM_STATE_INVALID);
g_return_val_if_fail (m->priv->is_server && !m->priv->is_client, G_DBUS_AUTH_MECHANISM_STATE_INVALID);
return m->priv->state;
}
static void
mechanism_server_initiate (GDBusAuthMechanism *mechanism,
const gchar *initial_response,
gsize initial_response_len)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
g_return_if_fail (!m->priv->is_server && !m->priv->is_client);
m->priv->is_server = TRUE;
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
if (initial_response != NULL && initial_response_len > 0)
{
#ifdef G_OS_UNIX
gint64 uid;
gchar *endp;
uid = g_ascii_strtoll (initial_response, &endp, 10);
if (*endp == '\0')
{
if (uid == getuid ())
{
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND;
}
}
#elif defined(G_OS_WIN32)
gchar *sid;
sid = _g_win32_current_process_sid_string (NULL);
if (g_strcmp0 (initial_response, sid) == 0)
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND;
g_free (sid);
#else
#error Please implement for your OS
#endif
}
}
static void
mechanism_server_data_receive (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
gchar **tokens;
const gchar *client_challenge;
const gchar *alleged_sha1;
gchar *sha1;
g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
g_return_if_fail (m->priv->is_server && !m->priv->is_client);
g_return_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA);
tokens = NULL;
sha1 = NULL;
tokens = g_strsplit (data, " ", 0);
if (g_strv_length (tokens) != 2)
{
g_free (m->priv->reject_reason);
m->priv->reject_reason = g_strdup_printf ("Malformed data '%s'", data);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
goto out;
}
client_challenge = tokens[0];
alleged_sha1 = tokens[1];
sha1 = generate_sha1 (m->priv->server_challenge, client_challenge, m->priv->cookie);
if (g_strcmp0 (sha1, alleged_sha1) == 0)
{
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_ACCEPTED;
}
else
{
g_free (m->priv->reject_reason);
m->priv->reject_reason = g_strdup_printf ("SHA-1 mismatch");
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
}
out:
g_strfreev (tokens);
g_free (sha1);
}
static gchar *
mechanism_server_data_send (GDBusAuthMechanism *mechanism,
gsize *out_data_len)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
gchar *s;
gint cookie_id;
const gchar *cookie_context;
GError *error;
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
g_return_val_if_fail (m->priv->is_server && !m->priv->is_client, NULL);
g_return_val_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND, NULL);
s = NULL;
*out_data_len = 0;
/* TODO: use GDBusAuthObserver here to get the cookie context to use? */
cookie_context = "org_gtk_gdbus_general";
cookie_id = -1;
error = NULL;
if (!keyring_generate_entry (cookie_context,
&cookie_id,
&m->priv->cookie,
&error))
{
g_free (m->priv->reject_reason);
m->priv->reject_reason = g_strdup_printf ("Error adding entry to keyring: %s", error->message);
g_error_free (error);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
goto out;
}
m->priv->server_challenge = random_ascii_string (16);
s = g_strdup_printf ("%s %d %s",
cookie_context,
cookie_id,
m->priv->server_challenge);
*out_data_len = strlen (s);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA;
out:
return s;
}
static gchar *
mechanism_server_get_reject_reason (GDBusAuthMechanism *mechanism)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
g_return_val_if_fail (m->priv->is_server && !m->priv->is_client, NULL);
g_return_val_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_REJECTED, NULL);
return g_strdup (m->priv->reject_reason);
}
static void
mechanism_server_shutdown (GDBusAuthMechanism *mechanism)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
g_return_if_fail (m->priv->is_server && !m->priv->is_client);
m->priv->is_server = FALSE;
}
/* ---------------------------------------------------------------------------------------------------- */
static GDBusAuthMechanismState
mechanism_client_get_state (GDBusAuthMechanism *mechanism)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), G_DBUS_AUTH_MECHANISM_STATE_INVALID);
g_return_val_if_fail (m->priv->is_client && !m->priv->is_server, G_DBUS_AUTH_MECHANISM_STATE_INVALID);
return m->priv->state;
}
static gchar *
mechanism_client_initiate (GDBusAuthMechanism *mechanism,
gsize *out_initial_response_len)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
gchar *initial_response;
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
g_return_val_if_fail (!m->priv->is_server && !m->priv->is_client, NULL);
m->priv->is_client = TRUE;
*out_initial_response_len = 0;
#ifdef G_OS_UNIX
initial_response = g_strdup_printf ("%" G_GINT64_FORMAT, (gint64) getuid ());
#elif defined (G_OS_WIN32)
initial_response = _g_win32_current_process_sid_string (NULL);
#else
#error Please implement for your OS
#endif
if (initial_response)
{
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA;
*out_initial_response_len = strlen (initial_response);
}
else
{
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
}
return initial_response;
}
static void
mechanism_client_data_receive (GDBusAuthMechanism *mechanism,
const gchar *data,
gsize data_len)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
gchar **tokens;
const gchar *cookie_context;
guint cookie_id;
const gchar *server_challenge;
gchar *client_challenge;
gchar *endp;
gchar *cookie;
GError *error;
gchar *sha1;
g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
g_return_if_fail (m->priv->is_client && !m->priv->is_server);
g_return_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_WAITING_FOR_DATA);
tokens = NULL;
cookie = NULL;
client_challenge = NULL;
tokens = g_strsplit (data, " ", 0);
if (g_strv_length (tokens) != 3)
{
g_free (m->priv->reject_reason);
m->priv->reject_reason = g_strdup_printf ("Malformed data '%s'", data);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
goto out;
}
cookie_context = tokens[0];
cookie_id = g_ascii_strtoll (tokens[1], &endp, 10);
if (*endp != '\0')
{
g_free (m->priv->reject_reason);
m->priv->reject_reason = g_strdup_printf ("Malformed cookie_id '%s'", tokens[1]);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
goto out;
}
server_challenge = tokens[2];
error = NULL;
cookie = keyring_lookup_entry (cookie_context, cookie_id, &error);
if (cookie == NULL)
{
g_free (m->priv->reject_reason);
m->priv->reject_reason = g_strdup_printf ("Problems looking up entry in keyring: %s", error->message);
g_error_free (error);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_REJECTED;
goto out;
}
client_challenge = random_ascii_string (16);
sha1 = generate_sha1 (server_challenge, client_challenge, cookie);
m->priv->to_send = g_strdup_printf ("%s %s", client_challenge, sha1);
g_free (sha1);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND;
out:
g_strfreev (tokens);
g_free (cookie);
g_free (client_challenge);
}
static gchar *
mechanism_client_data_send (GDBusAuthMechanism *mechanism,
gsize *out_data_len)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_val_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism), NULL);
g_return_val_if_fail (m->priv->is_client && !m->priv->is_server, NULL);
g_return_val_if_fail (m->priv->state == G_DBUS_AUTH_MECHANISM_STATE_HAVE_DATA_TO_SEND, NULL);
g_assert (m->priv->to_send != NULL);
m->priv->state = G_DBUS_AUTH_MECHANISM_STATE_ACCEPTED;
*out_data_len = strlen (m->priv->to_send);
return g_strdup (m->priv->to_send);
}
static void
mechanism_client_shutdown (GDBusAuthMechanism *mechanism)
{
GDBusAuthMechanismSha1 *m = G_DBUS_AUTH_MECHANISM_SHA1 (mechanism);
g_return_if_fail (G_IS_DBUS_AUTH_MECHANISM_SHA1 (mechanism));
g_return_if_fail (m->priv->is_client && !m->priv->is_server);
m->priv->is_client = FALSE;
}
/* ---------------------------------------------------------------------------------------------------- */
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