1 files changed, 38 insertions, 0 deletions

diff --git a/src/firejail/fs.c b/src/firejail/fs.c
index 484b99537..63ffa8bff 100644
--- a/src/firejail/fs.c
+++ b/src/firejail/fs.c
@@ -814,6 +814,44 @@ void fs_basic_fs(void) {
 }
 
 
+
+char *fs_check_overlay_dir(const char *subdirname, int allow_reuse) {
+        // create ~/.firejail directory
+        struct stat s;
+        char *dirname;
+        if (asprintf(&dirname, "%s/.firejail", cfg.homedir) == -1)
+                errExit("asprintf");
+        if (stat(dirname, &s) == -1) {
+                /* coverity[toctou] */
+                if (mkdir(dirname, 0700))
+                        errExit("mkdir");
+                if (chown(dirname, getuid(), getgid()) < 0)
+                        errExit("chown");
+                if (chmod(dirname, 0700) < 0)
+                        errExit("chmod");
+        }
+        else if (is_link(dirname)) {
+                fprintf(stderr, "Error: invalid ~/.firejail directory\n");
+                exit(1);
+        }
+
+        free(dirname);
+
+        // check overlay directory
+        if (asprintf(&dirname, "%s/.firejail/%s", cfg.homedir, subdirname) == -1)
+                errExit("asprintf");
+        if (allow_reuse == 0) {
+                if (stat(dirname, &s) == 0) {
+                        fprintf(stderr, "Error: overlay directory already exists: %s\n", dirname);
+                        exit(1);
+                }
+        }
+
+        return dirname;
+}
+
+
+
 // mount overlayfs on top of / directory
 // mounting an overlay and chrooting into it:
 //