x11 work

4 files changed, 229 insertions, 1 deletions

diff --git a/src/firejail/firejail.h b/src/firejail/firejail.h
index 4babc58e7..acb49d246 100644
--- a/src/firejail/firejail.h
+++ b/src/firejail/firejail.h
@@ -46,6 +46,7 @@
 #define RUN_PULSE_DIR   "/run/firejail/mnt/pulse"
 #define RUN_DEVLOG_FILE "/run/firejail/mnt/devlog"
 
+#define RUN_WHITELIST_X11_DIR   "/run/firejail/mnt/orig-x11"
 #define RUN_WHITELIST_HOME_DIR  "/run/firejail/mnt/orig-home"   // default home directory masking
 #define RUN_WHITELIST_HOME_USER_DIR     "/run/firejail/mnt/orig-home-user"      // home directory whitelisting
 #define RUN_WHITELIST_TMP_DIR   "/run/firejail/mnt/orig-tmp"
@@ -520,5 +521,9 @@ char **build_paths(void);
 // fs_mkdir.c
 void fs_mkdir(const char *name);
 
+// x11.c
+void fs_x11(void);
+void x11_start(int argc, char **argv);
+
 #endif
 
diff --git a/src/firejail/main.c b/src/firejail/main.c
index f02da66aa..2a5ded984 100644
--- a/src/firejail/main.c
+++ b/src/firejail/main.c
@@ -263,6 +263,10 @@ static void run_cmd_and_exit(int i, int argc, char **argv) {
 #endif
                 exit(0);
         }
+        else if (strcmp(argv[i], "--x11") == 0) {
+                x11_start(argc, argv);
+                exit(0);
+        }
 #ifdef HAVE_NETWORK     
         else if (strncmp(argv[i], "--bandwidth=", 12) == 0) {
                 logargs(argc, argv);
diff --git a/src/firejail/sandbox.c b/src/firejail/sandbox.c
index 1ba655301..d43e1dac1 100644
--- a/src/firejail/sandbox.c
+++ b/src/firejail/sandbox.c
@@ -588,13 +588,15 @@ int sandbox(void* sandbox_arg) {
                 errno = 0;
                 int rv = nice(cfg.nice);
                 (void) rv;
-printf("nice rv %d\n", rv);             
                 if (errno) {
                         fprintf(stderr, "Warning: cannot set nice value\n");
                         errno = 0;
                 }
         }
         
+        // clean /tmp/.X11-unix sockets
+        fs_x11();
+        
         //****************************
         // set security filters
         //****************************
diff --git a/src/firejail/x11.c b/src/firejail/x11.c
new file mode 100644
index 000000000..5e8fb9bbd
--- /dev/null
+++ b/src/firejail/x11.c
@@ -0,0 +1,217 @@
+/*
+ * Copyright (C) 2014-2016 Firejail Authors
+ *
+ * This file is part of firejail project
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "firejail.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <sys/mount.h>
+
+void fs_x11(void) {
+        // extract display
+        char *d = getenv("DISPLAY");
+        if (!d)
+                return;
+        
+        int display;
+        int rv = sscanf(d, ":%d", &display);
+        if (rv != 1)
+                return;
+        if (arg_debug)
+                printf("DISPLAY %s, %d\n", d, display);
+
+        char *x11file;
+        if (asprintf(&x11file, "/tmp/.X11-unix/X%d", display) == -1)
+                errExit("asprintf");
+        struct stat s;
+        if (stat(x11file, &s) == -1)
+                return;
+
+        // keep a copy of real /tmp/.X11-unix directory in WHITELIST_TMP_DIR
+        rv = mkdir(RUN_WHITELIST_X11_DIR, 1777);
+        if (rv == -1)
+                errExit("mkdir");
+        if (chown(RUN_WHITELIST_X11_DIR, 0, 0) < 0)
+                errExit("chown");
+        if (chmod(RUN_WHITELIST_X11_DIR, 1777) < 0)
+                errExit("chmod");
+
+        if (mount("/tmp/.X11-unix", RUN_WHITELIST_X11_DIR, NULL, MS_BIND|MS_REC, NULL) < 0)
+                errExit("mount bind");
+
+        // mount tmpfs on /tmp/.X11-unix
+        if (arg_debug || arg_debug_whitelists)
+                printf("Mounting tmpfs on /tmp/.X11-unix directory\n");
+        if (mount("tmpfs", "/tmp/.X11-unix", "tmpfs", MS_NOSUID | MS_STRICTATIME | MS_REC,  "mode=1777,gid=0") < 0)
+                errExit("mounting tmpfs on /tmp");
+        fs_logger("mount tmpfs on /tmp/.X11-unix");
+
+        // create an empty file
+        FILE *fp = fopen(x11file, "w");
+        if (!fp) {
+                fprintf(stderr, "Error: cannot create empty file in x11 directory\n");
+                exit(1);
+        }
+        fclose(fp);
+
+        // set file properties
+        if (chown(x11file, s.st_uid, s.st_gid) < 0)
+                errExit("chown");
+        if (chmod(x11file, s.st_mode) < 0)
+                errExit("chmod");
+
+        // mount
+        char *wx11file;
+        if (asprintf(&wx11file, "%s/X%d", RUN_WHITELIST_X11_DIR, display) == -1)
+                errExit("asprintf");
+        if (mount(wx11file, x11file, NULL, MS_BIND|MS_REC, NULL) < 0)
+                errExit("mount bind");
+         fs_logger2("whitelist", x11file);
+
+        free(x11file);
+        free(wx11file);
+        
+        // block access to RUN_WHITELIST_X11_DIR
+         if (mount(RUN_RO_DIR, RUN_WHITELIST_X11_DIR, "none", MS_BIND, "mode=400,gid=0") == -1)
+                errExit("mount");
+         fs_logger2("blacklist", RUN_WHITELIST_X11_DIR);
+}
+
+
+void x11_start(int argc, char **argv) {
+        EUID_ASSERT();
+        int i;
+        struct stat s;
+        pid_t client = 0;
+        pid_t server = 0;
+        
+        // check xpra
+        if (stat("/usr/bin/xpra", &s) == -1) {
+                fprintf(stderr, "\nError: Xpra program was not found in /usr/bin directory, please install it:\n");
+                fprintf(stderr, "   Arch: sudo pacman -S xpra\n");
+                fprintf(stderr, "   Debian/Ubuntu/Mint: sudo apt-get install xpra\n");
+                fprintf(stderr, "   Fedora/CentOS: sudo yum install xpra\n");
+                fprintf(stderr, "   Gentoo: sudo emerge xpra\n\n");
+                exit(0);
+        }
+        
+        int display;
+        int found = 1;
+        for (i = 0; i < 100; i++) {
+                display = rand() % 1024;
+                char *fname;
+                if (asprintf(&fname, "/tmp/.X11-unix/X%d", display) == -1)
+                        errExit("asprintf");
+                if (stat(fname, &s) == -1) {
+                        found = 1;
+                        break;
+                }
+        }
+        if (!found) {
+                fprintf(stderr, "Error: cannot pick up a random X11 display number, exiting...\n");
+                exit(1);
+        }
+
+        // build the start command
+        int len = 50; // xpra start...
+        for (i = 0; i < argc; i++) {
+                len += strlen(argv[i]) + 1; // + ' '
+        }
+        
+        char *cmd1 = malloc(len + 1); // + '\0'
+        if (!cmd1)
+                errExit("malloc");
+        
+        sprintf(cmd1, "xpra start :%d --exit-with-children --start-child=\"", display);
+        char *ptr = cmd1 + strlen(cmd1);
+        for (i = 0; i < argc; i++) {
+                if (strcmp(argv[i], "--x11") == 0)
+                        continue;
+                ptr += sprintf(ptr, "%s ", argv[i]);
+        }
+        sprintf(ptr, "\"");
+        if (arg_debug)
+                printf("xpra server: %s\n", cmd1);      
+        
+        // build the attach command
+        char *cmd2;
+        if (asprintf(&cmd2, "xpra attach :%d", display) == -1)
+                errExit("asprintf");
+        if (arg_debug)
+                printf("xpra client: %s\n", cmd2);
+
+        signal(SIGHUP,SIG_IGN); // fix sleep(1`) below
+        server = fork();
+        if (server < 0)
+                errExit("fork");
+        if (server == 0) {
+                if (arg_debug)
+                        printf("Starting xpra...\n");
+        
+                char *a[4];
+                a[0] = "/bin/bash";
+                a[1] = "-c";
+                a[2] = cmd1;
+                a[3] = NULL;
+        
+                execvp(a[0], a); 
+                perror("execvp");
+                exit(1);
+        }
+        sleep(1);
+        if (arg_debug) {
+                printf("X11 sockets: "); fflush(0);
+                int rv = system("ls /tmp/.X11-unix");
+                (void) rv;
+        }
+
+        // check X11 socket
+        char *fname;
+        if (asprintf(&fname, "/tmp/.X11-unix/X%d", display) == -1)
+                errExit("asprintf");
+        if (stat(fname, &s) == -1) {
+                fprintf(stderr, "Error: failed to start xpra\n");
+                exit(1);
+        }
+        
+        // run attach command
+        client = fork();
+        if (client < 0)
+                errExit("fork");
+        if (client == 0) {
+                printf("\n*** Attaching to xpra display %d ***\n\n", display);
+                char *a[4];
+                a[0] = "/bin/bash";
+                a[1] = "-c";
+                a[2] = cmd2;
+                a[3] = NULL;
+        
+                execvp(a[0], a); 
+                perror("execvp");
+                exit(1);
+        }
+        sleep(1);
+        
+        if (!arg_quiet)
+                printf("Xpra server pid %d, client pid %d\n", server, client);
+        exit(0);
+}