Fix race condition when setting up /run/firejail files (#1013)

1 files changed, 3 insertions, 1 deletions

diff --git a/src/firejail/util.c b/src/firejail/util.c
index acbc19234..9ad7271ba 100644
--- a/src/firejail/util.c
+++ b/src/firejail/util.c
@@ -821,7 +821,9 @@ void create_empty_dir_as_root(const char *dir, mode_t mode) {
                 if (arg_debug)
                         printf("Creating empty %s directory\n", dir);
                 /* coverity[toctou] */
-                if (mkdir(dir, mode) == -1)
+                // don't fail if directory already exists. This can be the case in a race
+                // condition, when two jails launch at the same time. See #1013
+                if (mkdir(dir, mode) == -1 && errno != EEXIST)
                         errExit("mkdir");
                 if (set_perms(dir, 0, 0, mode))
                         errExit("set_perms");