Set signal handlers directly after the fork(2), so that we avoid

situations, where the privileged child dies before the unprivileged
parent has set a signal handler for SIGCHLD.

ok deraadt@ canacar@

1 files changed, 13 insertions, 1 deletions

diff --git a/usr.sbin/tcpdump/privsep.c b/usr.sbin/tcpdump/privsep.c
index 9f27b403c7f..275cc52a5b7 100644
--- a/usr.sbin/tcpdump/privsep.c
+++ b/usr.sbin/tcpdump/privsep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: privsep.c,v 1.24 2006/04/22 17:24:33 moritz Exp $	*/
+/*	$OpenBSD: privsep.c,v 1.25 2006/04/22 19:26:05 moritz Exp $	*/
 
 /*
  * Copyright (c) 2003 Can Erkin Acar
@@ -107,6 +107,8 @@ int		priv_fd = -1;
 volatile	pid_t child_pid = -1;
 static volatile	sig_atomic_t cur_state = STATE_INIT;
 
+extern void	set_slave_signals(void);
+
 static void	impl_open_bpf(int, int *);
 static void	impl_open_dump(int, const char *);
 static void	impl_open_output(int, const char *);
@@ -134,6 +136,7 @@ priv_init(int argc, char **argv)
 	char *cmdbuf, *infile = NULL;
 	char *RFileName = NULL;
 	char *WFileName = NULL;
+	sigset_t allsigs, oset;
 
 	if (geteuid() != 0)
 		errx(1, "need root privileges");
@@ -146,6 +149,9 @@ priv_init(int argc, char **argv)
 	if (socketpair(AF_LOCAL, SOCK_STREAM, PF_UNSPEC, socks) == -1)
 		err(1, "socketpair() failed");
 
+	sigfillset(&allsigs);
+	sigprocmask(SIG_BLOCK, &allsigs, &oset);
+
 	child_pid = fork();
 	if (child_pid < 0)
 		err(1, "fork() failed");
@@ -173,9 +179,15 @@ priv_init(int argc, char **argv)
 
 		close(socks[0]);
 		priv_fd = socks[1];
+
+		set_slave_signals();
+		sigprocmask(SIG_SETMASK, &oset, NULL);
+
 		return (0);
 	}
 
+	sigprocmask(SIG_SETMASK, &oset, NULL);
+
 	/* Child - drop suid privileges */
 	gid = getgid();
 	uid = getuid();