[openssh-commits] [openssh] 04/06: upstream: Instead of using possibly complex ssh_signal(), write all

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djm pushed a commit to branch master
in repository openssh.

commit d6bcd13297c2ab8b528df5a6898f994734849031
Author: deraadt at openbsd.org <deraadt at openbsd.org>
AuthorDate: Wed Jun 26 23:16:52 2024 +0000

    upstream: Instead of using possibly complex ssh_signal(), write all
    
    the parts of the grace_alarm_handler() using the exact things allowed by the
    signal-safe rules.  This is a good rule of thumb: Handlers should be written
    to either set a global volatile sig_atomic_t inspected from outside, and/or
    directly perform only safe operations listed in our sigaction(2) manual page.
    ok djm markus
    
    OpenBSD-Commit-ID: 14168ae8368aab76e4ed79e17a667cb46f404ecd
---
 sshd-session.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/sshd-session.c b/sshd-session.c
index 7ab1ea47..fe6ae7f3 100644
--- a/sshd-session.c
+++ b/sshd-session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd-session.c,v 1.3 2024/06/06 17:15:25 djm Exp $ */
+/* $OpenBSD: sshd-session.c,v 1.4 2024/06/26 23:16:52 deraadt Exp $ */
 /*
  * SSH2 implementation:
  * Privilege Separation:
@@ -197,6 +197,8 @@ static void do_ssh2_kex(struct ssh *);
 
 /*
  * Signal handler for the alarm after the login grace period has expired.
+ * As usual, this may only take signal-safe actions, even though it is
+ * terminal.
  */
 static void
 grace_alarm_handler(int sig)
@@ -206,7 +208,14 @@ grace_alarm_handler(int sig)
 	 * keys command helpers or privsep children.
 	 */
 	if (getpgid(0) == getpid()) {
-		ssh_signal(SIGTERM, SIG_IGN);
+		struct sigaction sa;
+
+		/* mask all other signals while in handler */
+		memset(&sa, 0, sizeof(sa));
+		sa.sa_handler = SIG_IGN;
+		sigfillset(&sa.sa_mask);
+		sa.sa_flags = SA_RESTART;
+		(void)sigaction(SIGTERM, &sa, NULL);
 		kill(0, SIGTERM);
 	}
 	_exit(EXIT_LOGIN_GRACE);

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