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-rw-r--r--src/pam-x2go-children.c231
1 files changed, 231 insertions, 0 deletions
diff --git a/src/pam-x2go-children.c b/src/pam-x2go-children.c
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+++ b/src/pam-x2go-children.c
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+/*
+ * Copyright © 2012 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Ted Gould <ted@canonical.com>
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/un.h>
+#include <pwd.h>
+#include <grp.h>
+#include <errno.h>
+
+#include <security/pam_modules.h>
+#include <security/pam_modutil.h>
+#include <security/pam_appl.h>
+
+#include "pam-freerdp-children.h"
+#include "auth-check-path.h"
+
+void
+pam_sm_authenticate_helper (int *stdinpipe, const char* username, const char* rhost, const char* ruser, const char* rdomain)
+{
+
+ dup2(stdinpipe[0], 0);
+
+ char * args[5];
+
+ args[0] = (char *)auth_check_path;
+ args[1] = (char *)rhost;
+ args[2] = (char *)ruser;
+ args[3] = (char *)rdomain;
+ args[4] = NULL;
+
+ struct passwd * pwdent = getpwnam(username);
+ if (pwdent == NULL) {
+ _exit(EXIT_FAILURE);
+ }
+
+ /* Setting groups, but allowing EPERM as if we're not 100% root
+ we might not be able to do this */
+ if (setgroups(1, &pwdent->pw_gid) != 0 && errno != EPERM) {
+ _exit(EXIT_FAILURE);
+ }
+
+ if (setgid(pwdent->pw_gid) < 0 || setuid(pwdent->pw_uid) < 0 ||
+ setegid(pwdent->pw_gid) < 0 || seteuid(pwdent->pw_uid) < 0) {
+ _exit(EXIT_FAILURE);
+ }
+
+ if (clearenv() != 0) {
+ _exit(EXIT_FAILURE);
+ }
+
+ if (chdir(pwdent->pw_dir) != 0) {
+ _exit(EXIT_FAILURE);
+ }
+
+ setenv("HOME", pwdent->pw_dir, 1);
+
+ execvp(args[0], args);
+ _exit(0);
+}
+
+int
+session_socket_handler (struct passwd * pwdent, int readypipe, const char * ruser, const char * rhost, const char * rdomain, const char * password)
+{
+ /* Socket stuff */
+ int socketfd = 0;
+ struct sockaddr_un socket_addr;
+
+ /* Connected user */
+ socklen_t connected_addr_size;
+ int connectfd = 0;
+ struct sockaddr_un connected_addr;
+
+ /* Our buffer */
+ char * buffer = NULL;
+ int buffer_len = 0;
+ int buffer_fill = 0;
+
+ /* Track write out */
+ int writedata = 0;
+
+ /* Track ready writing */
+ int readywrite = 0;
+
+ /* Setting groups, but allowing EPERM as if we're not 100% root
+ we might not be able to do this */
+ if (setgroups(1, &pwdent->pw_gid) != 0 && errno != EPERM) {
+ _exit(EXIT_FAILURE);
+ }
+
+ if (setgid(pwdent->pw_gid) < 0 || setuid(pwdent->pw_uid) < 0 ||
+ setegid(pwdent->pw_gid) < 0 || seteuid(pwdent->pw_uid) < 0) {
+ /* Don't need to clean up yet */
+ return EXIT_FAILURE;
+ }
+
+ if (clearenv() != 0) {
+ /* Don't need to clean up yet */
+ return EXIT_FAILURE;
+ }
+
+ if (chdir(pwdent->pw_dir) != 0) {
+ /* Don't need to clean up yet */
+ return EXIT_FAILURE;
+ }
+
+ if (rdomain[0] == '\0') {
+ rdomain = ".";
+ }
+
+ /* Build this up as a buffer so we can just write it and see that
+ very, very clearly */
+ buffer_len += strlen(ruser) + 1; /* Add one for the space */
+ buffer_len += strlen(rhost) + 1; /* Add one for the space */
+ buffer_len += strlen(rdomain) + 1; /* Add one for the space */
+ buffer_len += strlen(password) + 1; /* Add one for the NULL */
+
+ if (buffer_len < 5) {
+ /* Don't need to clean up yet */
+ return EXIT_FAILURE;
+ }
+
+ buffer = malloc(buffer_len);
+
+ if (buffer == NULL) {
+ /* Don't need to clean up yet */
+ return EXIT_FAILURE;
+ }
+
+ /* Lock the buffer before writing */
+ if (mlock(buffer, buffer_len) != 0) {
+ /* We can't lock, we go home */
+ goto cleanup;
+ }
+
+ buffer_fill = snprintf(buffer, buffer_len, "%s %s %s %s", ruser, password, rdomain, rhost);
+ if (buffer_fill > buffer_len) {
+ /* This really shouldn't happen, but if for some reason we have an
+ difference between they way that the lengths are calculated we want
+ to catch that. */
+ goto cleanup;
+ }
+
+ /* Make our socket and bind it */
+ socketfd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (socketfd < 0) {
+ goto cleanup;
+ }
+
+ memset(&socket_addr, 0, sizeof(struct sockaddr_un));
+ socket_addr.sun_family = AF_UNIX;
+ strncpy(socket_addr.sun_path, pwdent->pw_dir, sizeof(socket_addr.sun_path) - 1);
+ strncpy(socket_addr.sun_path + strlen(pwdent->pw_dir), "/.freerdp-socket", (sizeof(socket_addr.sun_path) - strlen(pwdent->pw_dir)) - 1);
+
+ /* We bind the socket before forking so that we ensure that
+ there isn't a race condition to get to it. Things will block
+ otherwise. */
+ if (bind(socketfd, (struct sockaddr *)&socket_addr, sizeof(struct sockaddr_un)) < 0) {
+ goto cleanup;
+ }
+
+ /* Set the socket file permissions to be 600 and the user and group
+ to be the guest user. NOTE: This won't protect on BSD */
+ if (chmod(socket_addr.sun_path, S_IRUSR | S_IWUSR) != 0 ||
+ chown(socket_addr.sun_path, pwdent->pw_uid, pwdent->pw_gid) != 0) {
+ goto cleanup;
+ }
+
+ if (listen(socketfd, 1) < 0) {
+ goto cleanup;
+ }
+
+ readywrite = write(readypipe, ALL_GOOD_SIGNAL, strlen(ALL_GOOD_SIGNAL) + 1);
+ if (readywrite != strlen(ALL_GOOD_SIGNAL) + 1) {
+ goto cleanup;
+ }
+
+ connected_addr_size = sizeof(struct sockaddr_un);
+ connectfd = accept(socketfd, (struct sockaddr *)&connected_addr, &connected_addr_size);
+ if (connectfd < 0) {
+ goto cleanup;
+ }
+
+ writedata = write(connectfd, buffer, buffer_len);
+
+cleanup:
+ if (socketfd != 0) {
+ close(socketfd);
+ }
+ if (connectfd != 0) {
+ close(connectfd);
+ }
+
+ if (buffer != NULL) {
+ memset(buffer, 0, buffer_len);
+ munlock(buffer, buffer_len);
+ free(buffer);
+ buffer = NULL;
+ }
+
+ /* This should be only true on the write, so we can use this to check
+ out as writedata is init to 0 */
+ if (writedata == buffer_len) {
+ _exit (0);
+ }
+
+ _exit(EXIT_FAILURE);
+}
+