1 files changed, 28 insertions, 35 deletions

diff --git a/src/firejail/fs_home.c b/src/firejail/fs_home.c
index 4bcefa443..eab952eb8 100644
--- a/src/firejail/fs_home.c
+++ b/src/firejail/fs_home.c
@@ -42,15 +42,14 @@ static void skel(const char *homedir, uid_t u, gid_t g) {
                 // copy skel files
                 if (asprintf(&fname, "%s/.zshrc", homedir) == -1)
                         errExit("asprintf");
-                struct stat s;
                 // don't copy it if we already have the file
-                if (stat(fname, &s) == 0)
+                if (access(fname, F_OK) == 0)
                         return;
-                if (is_link(fname)) { // stat on dangling symlinks fails, try again using lstat
+                if (is_link(fname)) { // access(3) on dangling symlinks fails, try again using lstat
                         fprintf(stderr, "Error: invalid %s file\n", fname);
                         exit(1);
                 }
-                if (stat("/etc/skel/.zshrc", &s) == 0) {
+                if (access("/etc/skel/.zshrc", R_OK) == 0) {
                         copy_file_as_user("/etc/skel/.zshrc", fname, u, g, 0644); // regular user
                         fs_logger("clone /etc/skel/.zshrc");
                         fs_logger2("clone", fname);
@@ -67,16 +66,14 @@ static void skel(const char *homedir, uid_t u, gid_t g) {
                 // copy skel files
                 if (asprintf(&fname, "%s/.cshrc", homedir) == -1)
                         errExit("asprintf");
-                struct stat s;
-
                 // don't copy it if we already have the file
-                if (stat(fname, &s) == 0)
+                if (access(fname, F_OK) == 0)
                         return;
-                if (is_link(fname)) { // stat on dangling symlinks fails, try again using lstat
+                if (is_link(fname)) { // access(3) on dangling symlinks fails, try again using lstat
                         fprintf(stderr, "Error: invalid %s file\n", fname);
                         exit(1);
                 }
-                if (stat("/etc/skel/.cshrc", &s) == 0) {
+                if (access("/etc/skel/.cshrc", R_OK) == 0) {
                         copy_file_as_user("/etc/skel/.cshrc", fname, u, g, 0644); // regular user
                         fs_logger("clone /etc/skel/.cshrc");
                         fs_logger2("clone", fname);
@@ -93,15 +90,14 @@ static void skel(const char *homedir, uid_t u, gid_t g) {
                 // copy skel files
                 if (asprintf(&fname, "%s/.bashrc", homedir) == -1)
                         errExit("asprintf");
-                struct stat s;
                 // don't copy it if we already have the file
-                if (stat(fname, &s) == 0)
+                if (access(fname, F_OK) == 0)
                         return;
-                if (is_link(fname)) { // stat on dangling symlinks fails, try again using lstat
+                if (is_link(fname)) { // access(3) on dangling symlinks fails, try again using lstat
                         fprintf(stderr, "Error: invalid %s file\n", fname);
                         exit(1);
                 }
-                if (stat("/etc/skel/.bashrc", &s) == 0) {
+                if (access("/etc/skel/.bashrc", R_OK) == 0) {
                         copy_file_as_user("/etc/skel/.bashrc", fname, u, g, 0644); // regular user
                         fs_logger("clone /etc/skel/.bashrc");
                         fs_logger2("clone", fname);
@@ -122,8 +118,8 @@ static int store_xauthority(void) {
                 errExit("asprintf");
 
         struct stat s;
-        if (stat(src, &s) == 0) {
-                if (is_link(src)) {
+        if (lstat_as_user(src, &s) == 0) {
+                if (S_ISLNK(s.st_mode)) {
                         fwarning("invalid .Xauthority file\n");
                         free(src);
                         return 0;
@@ -161,11 +157,11 @@ static int store_asoundrc(void) {
                 errExit("asprintf");
 
         struct stat s;
-        if (stat(src, &s) == 0) {
-                if (is_link(src)) {
+        if (lstat_as_user(src, &s) == 0) {
+                if (S_ISLNK(s.st_mode)) {
                         // make sure the real path of the file is inside the home directory
                         /* coverity[toctou] */
-                        char* rp = realpath(src, NULL);
+                        char *rp = realpath_as_user(src);
                         if (!rp) {
                                 fprintf(stderr, "Error: Cannot access %s\n", src);
                                 exit(1);
@@ -234,6 +230,7 @@ static void copy_asoundrc(void) {
         }
 
         copy_file_as_user(src, dest, getuid(), getgid(), S_IRUSR | S_IWUSR); // regular user
+        selinux_relabel_path(dest, src);
         fs_logger2("clone", dest);
         free(dest);
 
@@ -262,6 +259,7 @@ void fs_private_homedir(void) {
         if (arg_debug)
                 printf("Mount-bind %s on top of %s\n", private_homedir, homedir);
         // get file descriptors for homedir and private_homedir, fails if there is any symlink
+        EUID_USER();
         int src = safer_openat(-1, private_homedir, O_PATH|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC);
         if (src == -1)
                 errExit("opening private directory");
@@ -286,17 +284,10 @@ void fs_private_homedir(void) {
                 exit(1);
         }
         // mount via the links in /proc/self/fd
-        char *proc_src, *proc_dst;
-        if (asprintf(&proc_src, "/proc/self/fd/%d", src) == -1)
-                errExit("asprintf");
-        if (asprintf(&proc_dst, "/proc/self/fd/%d", dst) == -1)
-                errExit("asprintf");
-        if (mount(proc_src, proc_dst, NULL, MS_NOSUID | MS_NODEV | MS_BIND | MS_REC, NULL) < 0)
+        EUID_ROOT();
+        if (bind_mount_by_fd(src, dst))
                 errExit("mount bind");
-        free(proc_src);
-        free(proc_dst);
-        close(src);
-        close(dst);
+
         // check /proc/self/mountinfo to confirm the mount is ok
         MountData *mptr = get_last_mount();
         size_t len = strlen(homedir);
@@ -304,6 +295,8 @@ void fs_private_homedir(void) {
            (*(mptr->dir + len) != '\0' && *(mptr->dir + len) != '/'))
                 errLogExit("invalid private mount");
 
+        close(src);
+        close(dst);
         fs_logger3("mount-bind", private_homedir, homedir);
         fs_logger2("whitelist", homedir);
 // preserve mode and ownership
@@ -438,6 +431,7 @@ void fs_check_private_cwd(const char *dir) {
 // --private-home
 //***********************************************************************************
 static char *check_dir_or_file(const char *name) {
+        EUID_ASSERT();
         assert(name);
 
         // basic checks
@@ -498,6 +492,7 @@ errexit:
 }
 
 static void duplicate(char *name) {
+        EUID_ASSERT();
         char *fname = check_dir_or_file(name);
 
         if (arg_debug)
@@ -553,10 +548,10 @@ void fs_private_home_list(void) {
         selinux_relabel_path(RUN_HOME_DIR, homedir);
         fs_logger_print();      // save the current log
 
+        // copy the list of files in the new home directory
+        EUID_USER();
         if (arg_debug)
                 printf("Copying files in the new home:\n");
-
-        // copy the list of files in the new home directory
         char *dlist = strdup(cfg.home_private_keep);
         if (!dlist)
                 errExit("strdup");
@@ -589,13 +584,11 @@ void fs_private_home_list(void) {
                 exit(1);
         }
         // mount using the file descriptor
-        char *proc;
-        if (asprintf(&proc, "/proc/self/fd/%d", fd) == -1)
-                errExit("asprintf");
-        if (mount(RUN_HOME_DIR, proc, NULL, MS_BIND|MS_REC, NULL) < 0)
+        EUID_ROOT();
+        if (bind_mount_path_to_fd(RUN_HOME_DIR, fd))
                 errExit("mount bind");
-        free(proc);
         close(fd);
+
         // check /proc/self/mountinfo to confirm the mount is ok
         MountData *mptr = get_last_mount();
         if (strcmp(mptr->dir, homedir) != 0 || strcmp(mptr->fstype, "tmpfs") != 0)