mirror of
git://git.gnupg.org/gnupg.git
synced 2025-07-03 22:56:33 +02:00
Keep on hacking on g13. A simple --create and --mount does now work.
A hacked up encfs is required.
This commit is contained in:
Werner Koch
parent
9b345f2a8a
commit
536b6ab09f
24 changed files with 1801 additions and 26 deletions
413
g13/be-encfs.c
413
g13/be-encfs.c
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@ -23,12 +23,301 @@
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <assert.h>
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#include "g13.h"
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#include "i18n.h"
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#include "keyblob.h"
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#include "be-encfs.h"
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#include "runner.h"
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#include "../common/exechelp.h"
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/* Command values used to run the encfs tool. */
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enum encfs_cmds
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{
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ENCFS_CMD_CREATE,
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ENCFS_CMD_MOUNT,
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ENCFS_CMD_UMOUNT
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};
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/* An object to keep the private state of the encfs tool. It is
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released by encfs_handler_cleanup. */
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struct encfs_parm_s
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{
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enum encfs_cmds cmd; /* The current command. */
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tupledesc_t tuples; /* NULL or the tuples object. */
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char *mountpoint; /* The mountpoint. */
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};
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typedef struct encfs_parm_s *encfs_parm_t;
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static gpg_error_t
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send_cmd_bin (runner_t runner, const void *data, size_t datalen)
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{
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return runner_send_line (runner, data, datalen);
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}
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static gpg_error_t
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send_cmd (runner_t runner, const char *string)
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{
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log_debug ("sending command -->%s<--\n", string);
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return send_cmd_bin (runner, string, strlen (string));
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}
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static void
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run_umount_helper (const char *mountpoint)
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{
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gpg_error_t err;
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const char pgmname[] = "/usr/bin/fusermount";
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const char *args[3];
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args[0] = "-u";
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args[1] = mountpoint;
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args[2] = NULL;
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err = gnupg_spawn_process_detached (pgmname, args, NULL);
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if (err)
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log_error ("failed to run `%s': %s\n",
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pgmname, gpg_strerror (err));
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}
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/* Handle one line of the encfs tool's output. This function is
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allowed to modify the content of BUFFER. */
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static gpg_error_t
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handle_status_line (runner_t runner, const char *line,
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enum encfs_cmds cmd, tupledesc_t tuples)
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{
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gpg_error_t err;
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/* Check that encfs understands our new options. */
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if (!strncmp (line, "$STATUS$", 8))
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{
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for (line +=8; *line && spacep (line); line++)
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;
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log_info ("got status `%s'\n", line);
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if (!strcmp (line, "fuse_main_start"))
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{
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/* Send a special error code back to let the caller know
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that everything has been setup by encfs. */
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err = gpg_error (GPG_ERR_UNFINISHED);
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}
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else
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err = 0;
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}
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else if (!strncmp (line, "$PROMPT$", 8))
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{
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for (line +=8; *line && spacep (line); line++)
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;
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log_info ("got prompt `%s'\n", line);
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if (!strcmp (line, "create_root_dir"))
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err = send_cmd (runner, cmd == ENCFS_CMD_CREATE? "y":"n");
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else if (!strcmp (line, "create_mount_point"))
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err = send_cmd (runner, "y");
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else if (!strcmp (line, "passwd")
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|| !strcmp (line, "new_passwd"))
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{
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if (tuples)
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{
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size_t n;
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const void *value;
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value = find_tuple (tuples, KEYBLOB_TAG_ENCKEY, &n);
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if (!value)
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err = gpg_error (GPG_ERR_INV_SESSION_KEY);
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else if ((err = send_cmd_bin (runner, value, n)))
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{
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if (gpg_err_code (err) == GPG_ERR_BUG
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&& gpg_err_source (err) == GPG_ERR_SOURCE_DEFAULT)
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err = gpg_error (GPG_ERR_INV_SESSION_KEY);
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}
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}
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else
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err = gpg_error (GPG_ERR_NO_DATA);
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}
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else
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err = send_cmd (runner, ""); /* Default to send an empty line. */
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}
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else if (strstr (line, "encfs: unrecognized option '"))
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err = gpg_error (GPG_ERR_INV_ENGINE);
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else
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err = 0;
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return err;
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}
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/* The main processing function as used by the runner. */
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static gpg_error_t
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encfs_handler (void *opaque, runner_t runner, const char *status_line)
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{
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encfs_parm_t parm = opaque;
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gpg_error_t err;
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if (!parm || !runner)
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return gpg_error (GPG_ERR_BUG);
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if (!status_line)
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{
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/* Runner requested internal flushing - nothing to do here. */
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return 0;
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}
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err = handle_status_line (runner, status_line, parm->cmd, parm->tuples);
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if (gpg_err_code (err) == GPG_ERR_UNFINISHED
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&& gpg_err_source (err) == GPG_ERR_SOURCE_DEFAULT)
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{
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err = 0;
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/* No more need for the tuples. */
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destroy_tupledesc (parm->tuples);
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parm->tuples = NULL;
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if (parm->cmd == ENCFS_CMD_CREATE)
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{
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/* The encfs tool keeps on running after creation of the
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container. We don't want that and thus need to stop the
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encfs process. */
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run_umount_helper (parm->mountpoint);
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/* In case the umount helper does not work we try to kill
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the engine. FIXME: We should figure out how to make
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fusermount work. */
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runner_cancel (runner);
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}
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}
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return err;
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}
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/* Called by the runner to cleanup the private data. */
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static void
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encfs_handler_cleanup (void *opaque)
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{
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encfs_parm_t parm = opaque;
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if (!parm)
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return;
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destroy_tupledesc (parm->tuples);
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xfree (parm->mountpoint);
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xfree (parm);
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}
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/* Run the encfs tool. */
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static gpg_error_t
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run_encfs_tool (ctrl_t ctrl, enum encfs_cmds cmd,
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const char *rawdir, const char *mountpoint, tupledesc_t tuples)
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{
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gpg_error_t err;
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encfs_parm_t parm;
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runner_t runner = NULL;
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int outbound[2] = { -1, -1 };
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int inbound[2] = { -1, -1 };
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const char *pgmname;
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const char *argv[10];
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pid_t pid = (pid_t)(-1);
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int idx;
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(void)ctrl;
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parm = xtrycalloc (1, sizeof *parm);
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if (!parm)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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parm->cmd = cmd;
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parm->tuples = ref_tupledesc (tuples);
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parm->mountpoint = xtrystrdup (mountpoint);
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if (!parm->mountpoint)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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{
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static int namecounter;
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char buffer[50];
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snprintf (buffer, sizeof buffer, "encfs-%d", ++namecounter);
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err = runner_new (&runner, buffer);
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if (err)
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goto leave;
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}
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err = gnupg_create_inbound_pipe (inbound);
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if (!err)
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err = gnupg_create_outbound_pipe (outbound);
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if (err)
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{
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log_error (_("error creating a pipe: %s\n"), gpg_strerror (err));
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goto leave;
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}
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pgmname = "/usr/bin/encfs";
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idx = 0;
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argv[idx++] = "-f";
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argv[idx++] = "-v";
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argv[idx++] = "--stdinpass";
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argv[idx++] = "--annotate";
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argv[idx++] = rawdir;
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argv[idx++] = mountpoint;
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argv[idx++] = NULL;
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assert (idx <= DIM (argv));
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err = gnupg_spawn_process_fd (pgmname, argv,
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outbound[0], -1, inbound[1], &pid);
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if (err)
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{
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log_error ("error spawning `%s': %s\n", pgmname, gpg_strerror (err));
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goto leave;
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}
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close (outbound[0]); outbound[0] = -1;
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close ( inbound[1]); inbound[1] = -1;
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runner_set_fds (runner, inbound[0], outbound[1]);
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inbound[0] = -1; /* Now owned by RUNNER. */
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outbound[1] = -1; /* Now owned by RUNNER. */
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runner_set_handler (runner, encfs_handler, encfs_handler_cleanup, parm);
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parm = NULL; /* Now owned by RUNNER. */
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runner_set_pid (runner, pid);
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pid = (pid_t)(-1); /* The process is now owned by RUNNER. */
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err = runner_spawn (runner);
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if (err)
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goto leave;
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log_info ("running `%s' in the background\n", pgmname);
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leave:
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if (inbound[0] != -1)
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close (inbound[0]);
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if (inbound[1] != -1)
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close (inbound[1]);
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if (outbound[0] != -1)
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close (outbound[0]);
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if (outbound[1] != -1)
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close (outbound[1]);
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if (pid != (pid_t)(-1))
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{
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gnupg_wait_process (pgmname, pid, NULL);
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}
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runner_release (runner);
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encfs_handler_cleanup (parm);
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return err;
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}
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/* See be_get_detached_name for a description. Note that the
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dispatcher code makes sure that NULL is stored at R_NAME before
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calling us. */
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@ -49,10 +338,134 @@ be_encfs_get_detached_name (const char *fname, char **r_name, int *r_isdir)
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}
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/* Create a new session key and append it as a tuple to the memory
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buffer MB.
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The EncFS daemon takes a passphrase from stdin and internally
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mangles it by means of some KDF from OpenSSL. We want to store a
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binary key but we need to make sure that certain characters are not
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used because the EncFS utility reads it from stdin and obviously
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acts on some of the characters. This we replace CR (in case of an
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MSDOS version of EncFS), LF (the delimiter used by EncFS) and Nul
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(because it is unlikely to work). We use 32 bytes (256 bit)
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because that is sufficient for the largest cipher (AES-256) and in
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addition gives enough margin for a possible entropy degradation by
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the KDF. */
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gpg_error_t
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be_encfs_create_new_keys (membuf_t *mb)
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{
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char *buffer;
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int i, j;
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/* Allocate a buffer of 32 bytes plus 8 spare bytes we may need to
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replace the unwanted values. */
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buffer = xtrymalloc_secure (32+8);
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if (!buffer)
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return gpg_error_from_syserror ();
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/* Randomize the buffer. STRONG random should be enough as it is a
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good compromise between security and performance. The
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anticipated usage of this tool is the quite often creation of new
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containers and thus this should not deplete the system's entropy
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tool too much. */
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gcry_randomize (buffer, 32+8, GCRY_STRONG_RANDOM);
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for (i=j=0; i < 32; i++)
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{
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if (buffer[i] == '\r' || buffer[i] == '\n' || buffer[i] == 0 )
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{
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/* Replace. */
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if (j == 8)
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{
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/* Need to get more random. */
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gcry_randomize (buffer+32, 8, GCRY_STRONG_RANDOM);
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j = 0;
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}
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buffer[i] = buffer[32+j];
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j++;
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}
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}
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/* Store the key. */
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append_tuple (mb, KEYBLOB_TAG_ENCKEY, buffer, 32);
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/* Free the temporary buffer. */
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wipememory (buffer, 32+8); /* A failsafe extra wiping. */
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xfree (buffer);
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return 0;
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}
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/* Create the container described by the filename FNAME and the keyblob
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information in TUPLES. */
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gpg_error_t
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be_encfs_create_container (ctrl_t ctrl, const char *fname, tupledesc_t tuples)
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{
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gpg_error_t err;
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int dummy;
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char *containername = NULL;
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char *mountpoint = NULL;
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err = be_encfs_get_detached_name (fname, &containername, &dummy);
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if (err)
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goto leave;
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mountpoint = xtrystrdup ("/tmp/.#g13_XXXXXX");
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if (!mountpoint)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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if (!mkdtemp (mountpoint))
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{
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err = gpg_error_from_syserror ();
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log_error (_("can't create directory `%s': %s\n"),
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"/tmp/g13-XXXXXX", gpg_strerror (err));
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goto leave;
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}
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err = run_encfs_tool (ctrl, ENCFS_CMD_CREATE, containername, mountpoint,
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tuples);
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/* In any case remove the temporary mount point. */
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if (rmdir (mountpoint))
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log_error ("error removing temporary mount point `%s': %s\n",
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mountpoint, gpg_strerror (gpg_error_from_syserror ()));
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leave:
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xfree (containername);
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xfree (mountpoint);
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return err;
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}
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/* Mount the container described by the filename FNAME and the keyblob
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information in TUPLES. */
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gpg_error_t
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be_encfs_mount_container (ctrl_t ctrl,
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const char *fname, const char *mountpoint,
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tupledesc_t tuples)
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{
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gpg_error_t err;
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int dummy;
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char *containername = NULL;
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if (!mountpoint)
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{
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log_error ("the encfs backend requires an explicit mountpoint\n");
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err = gpg_error (GPG_ERR_NOT_SUPPORTED);
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goto leave;
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}
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err = be_encfs_get_detached_name (fname, &containername, &dummy);
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if (err)
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goto leave;
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err = run_encfs_tool (ctrl, ENCFS_CMD_MOUNT, containername, mountpoint,
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tuples);
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leave:
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xfree (containername);
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return err;
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}
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