improve some error messages

2 files changed, 62 insertions, 42 deletions

diff --git a/src/firejail/fs.c b/src/firejail/fs.c
index f70c5ac8a..3ce2c7571 100644
--- a/src/firejail/fs.c
+++ b/src/firejail/fs.c
@@ -1195,73 +1195,78 @@ void fs_check_chroot_dir(const char *rootdir) {
         }
 
         // check /dev
-        fd = openat(parentfd, "dev", O_PATH|O_CLOEXEC);
+        char *dir = "dev";
+        fd = openat(parentfd, dir, O_PATH|O_CLOEXEC);
         if (fd == -1) {
-                fprintf(stderr, "Error: cannot open /dev in chroot directory\n");
-                exit(1);
+                if (errno == ENOENT)
+                        goto error1;
+                else
+                        goto error2;
         }
         if (fstat(fd, &s) == -1)
                 errExit("fstat");
-        if (!S_ISDIR(s.st_mode) || s.st_uid != 0) {
-                fprintf(stderr, "Error: chroot /dev should be a directory owned by root\n");
-                exit(1);
-        }
+        if (!S_ISDIR(s.st_mode) || s.st_uid != 0)
+                goto error3;
         close(fd);
 
         // check /var/tmp
-        fd = openat(parentfd, "var/tmp", O_PATH|O_CLOEXEC);
+        dir = "var/tmp";
+        fd = openat(parentfd, dir, O_PATH|O_CLOEXEC);
         if (fd == -1) {
-                fprintf(stderr, "Error: cannot open /var/tmp in chroot directory\n");
-                exit(1);
+                if (errno == ENOENT)
+                        goto error1;
+                else
+                        goto error2;
         }
         if (fstat(fd, &s) == -1)
                 errExit("fstat");
-        if (!S_ISDIR(s.st_mode) || s.st_uid != 0) {
-                fprintf(stderr, "Error: chroot /var/tmp should be a directory owned by root\n");
-                exit(1);
-        }
+        if (!S_ISDIR(s.st_mode) || s.st_uid != 0)
+                goto error3;
         close(fd);
 
         // check /proc
-        fd = openat(parentfd, "proc", O_PATH|O_CLOEXEC);
+        dir = "proc";
+        fd = openat(parentfd, dir, O_PATH|O_CLOEXEC);
         if (fd == -1) {
-                fprintf(stderr, "Error: cannot open /proc in chroot directory\n");
-                exit(1);
+                if (errno == ENOENT)
+                        goto error1;
+                else
+                        goto error2;
         }
         if (fstat(fd, &s) == -1)
                 errExit("fstat");
-        if (!S_ISDIR(s.st_mode) || s.st_uid != 0) {
-                fprintf(stderr, "Error: chroot /proc should be a directory owned by root\n");
-                exit(1);
-        }
+        if (!S_ISDIR(s.st_mode) || s.st_uid != 0)
+                goto error3;
         close(fd);
 
         // check /tmp
-        fd = openat(parentfd, "tmp", O_PATH|O_CLOEXEC);
+        dir = "tmp";
+        fd = openat(parentfd, dir, O_PATH|O_CLOEXEC);
         if (fd == -1) {
-                fprintf(stderr, "Error: cannot open /tmp in chroot directory\n");
-                exit(1);
+                if (errno == ENOENT)
+                        goto error1;
+                else
+                        goto error2;
         }
         if (fstat(fd, &s) == -1)
                 errExit("fstat");
-        if (!S_ISDIR(s.st_mode) || s.st_uid != 0) {
-                fprintf(stderr, "Error: chroot /tmp should be a directory owned by root\n");
-                exit(1);
-        }
+        if (!S_ISDIR(s.st_mode) || s.st_uid != 0)
+                goto error3;
         close(fd);
 
         // check /etc
-        fd = openat(parentfd, "etc", O_PATH|O_CLOEXEC);
+        dir = "etc";
+        fd = openat(parentfd, dir, O_PATH|O_CLOEXEC);
         if (fd == -1) {
-                fprintf(stderr, "Error: cannot open /etc in chroot directory\n");
-                exit(1);
+                if (errno == ENOENT)
+                        goto error1;
+                else
+                        goto error2;
         }
         if (fstat(fd, &s) == -1)
                 errExit("fstat");
-        if (!S_ISDIR(s.st_mode) || s.st_uid != 0) {
-                fprintf(stderr, "Error: chroot /etc should be a directory owned by root\n");
-                exit(1);
-        }
+        if (!S_ISDIR(s.st_mode) || s.st_uid != 0)
+                goto error3;
         if (((S_IWGRP|S_IWOTH) & s.st_mode) != 0) {
                 fprintf(stderr, "Error: only root user should be given write permission on chroot /etc\n");
                 exit(1);
@@ -1298,21 +1303,34 @@ void fs_check_chroot_dir(const char *rootdir) {
 
         // check x11 socket directory
         if (getenv("FIREJAIL_X11")) {
-                fd = openat(parentfd, "tmp/.X11-unix", O_PATH|O_CLOEXEC);
+                dir = "tmp/.X11-unix";
+                fd = openat(parentfd, dir, O_PATH|O_CLOEXEC);
                 if (fd == -1) {
-                        fprintf(stderr, "Error: cannot open /tmp/.X11-unix in chroot directory\n");
-                        exit(1);
+                        if (errno == ENOENT)
+                                goto error1;
+                        else
+                                goto error2;
                 }
                 if (fstat(fd, &s) == -1)
                         errExit("fstat");
-                if (!S_ISDIR(s.st_mode) || s.st_uid != 0) {
-                        fprintf(stderr, "Error: chroot /tmp/.X11-unix should be a directory owned by root\n");
-                        exit(1);
-                }
+                if (!S_ISDIR(s.st_mode) || s.st_uid != 0)
+                        goto error3;
                 close(fd);
         }
 
         close(parentfd);
+        return;
+
+error1:
+        fprintf(stderr, "Error: cannot find /%s in chroot directory\n", dir);
+        exit(1);
+error2:
+        perror("open");
+        fprintf(stderr, "Error: cannot open /%s in chroot directory\n", dir);
+        exit(1);
+error3:
+        fprintf(stderr, "Error: chroot /%s should be a directory owned by root\n", dir);
+        exit(1);
 }
 
 // chroot into an existing directory; mount exiting /dev and update /etc/resolv.conf
diff --git a/src/firejail/fs_home.c b/src/firejail/fs_home.c
index 47261d7c1..10232fa6e 100644
--- a/src/firejail/fs_home.c
+++ b/src/firejail/fs_home.c
@@ -393,6 +393,8 @@ static char *check_dir_or_file(const char *name) {
         // we allow only files in user home directory or symbolic links to files or directories owned by the user
         struct stat s;
         if (lstat(fname, &s) == 0 && S_ISLNK(s.st_mode)) {
+                if (strncmp(fname, cfg.homedir, strlen(cfg.homedir)) != 0 || fname[strlen(cfg.homedir)] != '/')
+                        goto errexit;
                 if (stat(fname, &s) == 0) {
                         if (s.st_uid != getuid()) {
                                 fprintf(stderr, "Error: symbolic link %s to file or directory not owned by the user\n", fname);