Kill off PAM thread if privsep slave dies (closes: #248125).

1 files changed, 9 insertions, 2 deletions

diff --git a/auth-pam.c b/auth-pam.c
index 36dbb7e15..361573807 100644
--- a/auth-pam.c
+++ b/auth-pam.c
@@ -93,10 +93,17 @@ static mysig_t sshpam_oldsig;
 static void 
 sshpam_sigchld_handler(int sig)
 {
+        signal(SIGCHLD, SIG_DFL);
         if (cleanup_ctxt == NULL)
                 return; /* handler called after PAM cleanup, shouldn't happen */
-        if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1)
-                return; /* couldn't wait for process */
+        if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
+             == -1) {
+                /* PAM thread has not exitted, privsep slave must have */
+                kill(cleanup_ctxt->pam_thread, SIGTERM);
+                if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0)
+                    == -1)
+                        return; /* could not wait */
+        }
         if (WIFSIGNALED(sshpam_thread_status) &&
             WTERMSIG(sshpam_thread_status) == SIGTERM)
                 return; /* terminated by pthread_cancel */