fix joining of sandboxes without shell

regressed in c764520b5aa343c00c3a73633511df039645973c

1 files changed, 5 insertions, 0 deletions

diff --git a/src/firejail/join.c b/src/firejail/join.c
index b62a1ca9d..5d73f71be 100644
--- a/src/firejail/join.c
+++ b/src/firejail/join.c
@@ -315,6 +315,11 @@ static int open_shell(void) {
                 fprintf(stderr, "Error: cannot open shell %s\n", cfg.shell);
                 exit(1);
         }
+
+        // pass file descriptor through to the final fexecve
+        if (asprintf(&cfg.keep_fd, "%s,%d", cfg.keep_fd ? cfg.keep_fd : "", fd) == -1)
+                errExit("asprintf");
+
         return fd;
 }