path: root/mail/mail-crypto.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */

/*
 * mail-crypto.h: OpenPGP en/decryption & signature code
 *
 * FIXME FIXME FIXME: This should be in its own library or component
 */

/*
 * Authors:
 *  Nathan Thompson-Amato <ndt@jps.net>
 *  Dan Winship <danw@helixcode.com>
 *
 *  Copyright 2000, Helix Code, Inc. (http://www.helixcode.com)
 *  Copyright 2000, Nathan Thompson-Amato
 *  Copyright 1999, 2000, Anthony Mulcahy
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
 *
 */

#include "config.h"

#ifdef PGP_PROGRAM
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include <gnome.h>

#include "mail.h"

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <signal.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <termios.h>
#include <unistd.h>
#include <signal.h>

static int
cleanup_child (pid_t child)
{
    int status;
    pid_t wait_result;
    sigset_t mask, omask;

    /* PGP5 closes fds before exiting, meaning this might be called
     * too early. So wait a bit for the result.
     */
    sigemptyset (&mask);
    sigaddset (&mask, SIGALRM);
    sigprocmask (SIG_BLOCK, &mask, &omask);
    alarm (1);
    wait_result = waitpid (child, &status, 0);
    alarm (0);
    sigprocmask (SIG_SETMASK, &omask, NULL);

    if (wait_result == -1 && errno == EINTR) {
        /* The child is hanging: send a friendly reminder. */
        kill (child, SIGTERM);
        sleep (1);
        wait_result = waitpid (child, &status, WNOHANG);
        if (wait_result == 0) {
            /* Still hanging; use brute force. */
            kill (child, SIGKILL);
            sleep (1);
            wait_result = waitpid (child, &status, WNOHANG);
        }
    }

    if (wait_result != -1 && WIFEXITED (status))
        return WEXITSTATUS (status);
    else
        return -1;
}

static void
cleanup_before_exec (int fd)
{
    int maxfd, i;

    maxfd = sysconf (_SC_OPEN_MAX);
    if (maxfd < 0)
        return;

    /* Loop over all fds. */
    for (i = 0; i < maxfd; i++) {
        if ((STDIN_FILENO != i) &&
            (STDOUT_FILENO != i) &&
            (STDERR_FILENO != i) &&
            (fd != i))
            close (i);
    }
}

static int
crypto_exec_with_passwd (char *path, char *argv[], const char *input,
             int passwd_fds[], const char *passphrase,
             char **output, char **diagnostics)
{
    fd_set fdset, write_fdset;
    int ip_fds[2], op_fds[2], diag_fds[2];
    int select_result, read_len, write_len;
        size_t tmp_len;
    pid_t child;
    char *buf, *diag_buf;
    const char *passwd_next, *input_next;
    size_t size, alloc_size, diag_size, diag_alloc_size;
        gboolean eof_seen, diag_eof_seen, passwd_eof_seen, input_eof_seen;
        size_t passwd_remaining, passwd_incr, input_remaining, input_incr;
    struct timeval timeout;
        long tmp;

    if ((pipe (ip_fds) < 0 ) ||
        (pipe (op_fds) < 0 ) ||
        (pipe (diag_fds) < 0 )) {
        *diagnostics = g_strdup_printf ("Couldn't create pipe to %s: "
                        "%s", PGP_PROGRAM,
                        g_strerror (errno));
        return 0;
    }

    if (!(child = fork ())) {
        /* In child */

                if ((dup2 (ip_fds[0], STDIN_FILENO) < 0 ) ||
            (dup2 (op_fds[1], STDOUT_FILENO) < 0 ) ||
            (dup2 (diag_fds[1], STDERR_FILENO) < 0 )) {
            _exit (255);
        }

        /* Dissociate from evolution-mail's controlling
         * terminal so that pgp/gpg won't be able to read from
         * it: PGP 2 will fall back to asking for the password
         * on /dev/tty if the passed-in password is incorrect.
         * This will make that fail rather than hanging.
         */
        setsid ();

        /* Close excess fds */
                cleanup_before_exec(passwd_fds[0]);

        execvp (path, argv);
        fprintf (stderr, "Could not execute %s: %s\n", argv[0],
             g_strerror (errno));
        _exit (255);
    } else if (child < 0) {
        *diagnostics = g_strdup_printf ("Cannot fork %s: %s",
                        argv[0], g_strerror (errno));
        return 0;
    }

    /* Parent */
    close (ip_fds[0]);
    close (op_fds[1]);
    close (diag_fds[1]);
    close (passwd_fds[0]);

    timeout.tv_sec = 10; /* timeout in seconds */
    timeout.tv_usec = 0;

    size = diag_size = 0;
    alloc_size = 4096;
    diag_alloc_size = 1024;
        eof_seen = diag_eof_seen = FALSE;

    buf = g_malloc (alloc_size);
    diag_buf = g_malloc (diag_alloc_size);

        passwd_next = passphrase;
        passwd_remaining = strlen (passphrase);
        passwd_incr = fpathconf (passwd_fds[1], _PC_PIPE_BUF);
    /* Use a reasonable default value on error. */
        if (passwd_incr <= 0)
        passwd_incr = 1024;
        passwd_eof_seen = FALSE;

    input_next = input;
    input_remaining = strlen (input);
    input_incr = fpathconf (ip_fds[1], _PC_PIPE_BUF);
    if (input_incr <= 0)
                input_incr = 1024;
    input_eof_seen = FALSE;

    while (!(eof_seen && diag_eof_seen)) {
        FD_ZERO (&fdset);
                if (!eof_seen)
            FD_SET (op_fds[0], &fdset);
                if (!diag_eof_seen)
            FD_SET (diag_fds[0], &fdset);

        FD_ZERO (&write_fdset);
                if (!passwd_eof_seen)
            FD_SET (passwd_fds[1], &write_fdset);
                if (!input_eof_seen)
            FD_SET (ip_fds[1], &write_fdset);

        select_result = select (FD_SETSIZE, &fdset, &write_fdset,
                    NULL, &timeout);
        if (select_result < 0) {
            if (errno == EINTR)
                continue;
            break;
        }
        if (select_result == 0) {
            /* timeout */
            break;
        }

                if (FD_ISSET (op_fds[0], &fdset)) {
            /* More output is available. */

            if (size + 4096 > alloc_size) {
                alloc_size += 4096;
                buf = g_realloc (buf , alloc_size);
            }
            read_len = read (op_fds[0], &buf[size],
                     alloc_size - size - 1);
            if (read_len < 0) {
                if (errno == EINTR)
                    continue;
                break;
            }
            if (read_len == 0)
                eof_seen = TRUE;
            size += read_len;
                }

                if (FD_ISSET(diag_fds[0], &fdset) ) {
            /* More stderr is available. */

            if (diag_size + 1024 > diag_alloc_size) {
                diag_alloc_size += 1024;
                diag_buf = g_realloc (diag_buf,
                              diag_alloc_size);
            }

            read_len = read (diag_fds[0], &diag_buf[diag_size],
                     diag_alloc_size - diag_size - 1);
            if (read_len < 0) {
                if (errno == EINTR)
                    continue;
                break;
            }
            if (read_len == 0)
                diag_eof_seen = TRUE;
            diag_size += read_len;
                }

                if (FD_ISSET(passwd_fds[1], &write_fdset)) {
            /* Ready for more password input. */

            tmp_len = passwd_incr;
            if (tmp_len > passwd_remaining)
                tmp_len = passwd_remaining;
            write_len = write (passwd_fds[1], passwd_next,
                       tmp_len);
            if (write_len < 0) {
                if (errno == EINTR)
                    continue;
                break;
            }
            passwd_next += write_len;
            passwd_remaining -= write_len;
            if (passwd_remaining == 0) {
                close (passwd_fds[1]);
                passwd_eof_seen = TRUE;
            }
                }

                if (FD_ISSET(ip_fds[1], &write_fdset)) {
            /* Ready for more ciphertext input. */

            tmp_len = input_incr;
            if (tmp_len > input_remaining)
                tmp_len = input_remaining;
            write_len = write (ip_fds[1], input_next, tmp_len);
            if (write_len < 0) {
                if (errno == EINTR)
                    continue;
                break;
            }
            input_next += write_len;
            input_remaining -= write_len;
            if (input_remaining == 0 ) {
                close (ip_fds[1]);
                input_eof_seen = TRUE;
            }
                }
    }

    buf[size] = 0;
    diag_buf[diag_size] = 0;
    close (op_fds[0]);
    close (diag_fds[0]);

    *output = buf;
    *diagnostics = diag_buf;

        return cleanup_child (child);
}

/*----------------------------------------------------------------------*
 *                     Public crypto functions
 *----------------------------------------------------------------------*/


char *
mail_crypto_openpgp_decrypt (const char *ciphertext, const char *passphrase,
                 CamelException *ex)
{
    int retval;
    char *path, *argv[12];
    int i;
    char *plaintext = NULL;
    char *diagnostics = NULL;
    int passwd_fds[2];
    char passwd_fd[32];

#ifndef PGP_PROGRAM
    camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                  "No GPG/PGP program available.");
    return NULL;
#endif

    if (pipe (passwd_fds) < 0) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("Couldn't create pipe to GPG/PGP: %s"),
                      g_strerror (errno));
        return NULL;
    }

    i = 0;
#if defined(GPG_PATH)
    path = GPG_PATH;

    argv[i++] = "gpg";
    argv[i++] = "--verbose";
    argv[i++] = "--yes";
    argv[i++] = "--batch";

    argv[i++] = "--output";
    argv[i++] = "-";            /* output to stdout */

    argv[i++] = "--decrypt";

    argv[i++] = "--passphrase-fd";
    sprintf (passwd_fd, "%d", passwd_fds[0]);
    argv[i++] = passwd_fd;
#elif defined(PGP5_PATH)
    path = PGP5_PATH;

    argv[i++] = "pgpv";
    argv[i++] = "-f";
    argv[i++] = "+batchmode=1";

    sprintf (passwd_fd, "PGPPASSFD=%d", passwd_fds[0]);
    putenv (passwd_fd);
#else
    path = PGP_PATH;

    argv[i++] = "pgp";
    argv[i++] = "-f";

    sprintf (passwd_fd, "PGPPASSFD=%d", passwd_fds[0]);
    putenv (passwd_fd);
#endif
    argv[i++] = NULL;

    retval = crypto_exec_with_passwd (path, argv, ciphertext, passwd_fds,
                      passphrase, &plaintext,
                      &diagnostics);
    if (retval != 0 || !*plaintext) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      "%s", diagnostics);
        g_free (plaintext);
        g_free (diagnostics);
        return NULL;
    }

    g_free (diagnostics);
    return plaintext;
}

#endif /* PGP_PROGRAM */