su: Verify default SIGCHLD handling.

The SIGCHLD handler could have been ignored by parent process.
Make sure that we have default handling activated.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>

diff --git a/login-utils/su-common.c b/login-utils/su-common.c
index 06282d21a1b313c97d56d96eb6b938d30d30be2a..e57ff64bdb60977e3cad3dd316d1812cee3bb54c 100644 (file)
--- a/login-utils/su-common.c
+++ b/login-utils/su-common.c
@@ -522,6 +522,7 @@ static void parent_setup_signals(struct su_context *su)
 
 static void create_watching_parent(struct su_context *su)
 {
+       struct sigaction action;
        int status;
 
        DBG(MISC, ul_debug("forking..."));
@@ -545,6 +546,19 @@ static void create_watching_parent(struct su_context *su)
 #endif
        fflush(stdout);                 /* ??? */
 
+       /* set default handler for SIGCHLD */
+       sigemptyset(&action.sa_mask);
+       action.sa_flags = 0;
+       action.sa_handler = SIG_DFL;
+       if (sigaction(SIGCHLD, &action, NULL)) {
+               supam_cleanup(su, PAM_ABORT);
+#ifdef USE_PTY
+               if (su->force_pty)
+                       ul_pty_cleanup(su->pty);
+#endif
+               err(EXIT_FAILURE, _("cannot set child signal handler"));
+       }
+
        switch ((int) (su->child = fork())) {
        case -1: /* error */
                supam_cleanup(su, PAM_ABORT);