1 files changed, 6 insertions, 0 deletions

diff --git a/src/firejail/shutdown.c b/src/firejail/shutdown.c
index 131f663d4..edaac7eb9 100644
--- a/src/firejail/shutdown.c
+++ b/src/firejail/shutdown.c
@@ -54,8 +54,14 @@ void shut(pid_t pid) {
                                 printf("Switching to pid %u, the first child process inside the sandbox\n", (unsigned) pid);
                         }
                 }
+                else {
+                        fprintf(stderr, "Error: this is not a firejail sandbox\n");
+                        exit(1);
+                }
                 free(comm);
         }
+        else
+                errExit("/proc/PID/comm");
 
         // check privileges for non-root users
         uid_t uid = getuid();