From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Sat, 23 Oct 2021 11:44:23 +0000 (+0200)
Subject: su: Verify default SIGCHLD handling.
X-Git-Tag: v2.38-rc1~90
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=312b64d9d1cedeac8d926cc503ffb4fbe023ade0;p=thirdparty%2Futil-linux.git

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 06282d21a1..e57ff64bdb 100644
--- 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);