Apply the correct fix for bin/50679: don't mess around with process groups

or the tty, just block selected signals in the parent like system(3) does.
Many thanks to bde for his assistance in finding the correct solution.

PR:		bin/50679

1 files changed, 19 insertions, 13 deletions

diff --git a/libutil/pw_util.c b/libutil/pw_util.c
index 5d831e0..053ac56 100644
--- a/libutil/pw_util.c
+++ b/libutil/pw_util.c
@@ -287,54 +287,60 @@ pw_mkdb(const char *user)
 int
 pw_edit(int notsetuid)
 {
+	struct sigaction sa, sa_int, sa_quit;
+	sigset_t sigset, oldsigset;
 	struct stat st1, st2;
 	const char *editor;
-	char *editcmd;
 	int pstat;
 
 	if ((editor = getenv("EDITOR")) == NULL)
 		editor = _PATH_VI;
 	if (stat(tempname, &st1) == -1)
 		return (-1);
+	sa.sa_handler = SIG_IGN;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = 0;
+	sigaction(SIGINT, &sa, &sa_int);
+	sigaction(SIGQUIT, &sa, &sa_quit);
+	sigemptyset(&sigset);
+	sigaddset(&sigset, SIGCHLD);
+	sigprocmask(SIG_BLOCK, &sigset, &oldsigset);
 	switch ((editpid = fork())) {
 	case -1:
 		return (-1);
 	case 0:
-		/* child */
+		sigaction(SIGINT, &sa_int, NULL);
+		sigaction(SIGQUIT,  &sa_quit, NULL);
+		sigprocmask(SIG_SETMASK, &oldsigset, NULL);
 		if (notsetuid) {
 			(void)setgid(getgid());
 			(void)setuid(getuid());
 		}
-		if (asprintf(&editcmd, "exec %s %s", editor, tempname) == NULL)
-			_exit(EXIT_FAILURE);
 		errno = 0;
-		execl(_PATH_BSHELL, "sh", "-c", editcmd, NULL);
-		free(editcmd);
+		execlp(editor, editor, tempname, NULL);
 		_exit(errno);
 	default:
 		/* parent */
 		break;
 	}
-	setpgid(editpid, editpid);
-	tcsetpgrp(1, editpid);
 	for (;;) {
 		if (waitpid(editpid, &pstat, WUNTRACED) == -1) {
 			unlink(tempname);
-			return (-1);
+			break;
 		} else if (WIFSTOPPED(pstat)) {
 			raise(WSTOPSIG(pstat));
-			tcsetpgrp(1, getpgid(editpid));
-			kill(editpid, SIGCONT);
 		} else if (WIFEXITED(pstat) && WEXITSTATUS(pstat) == 0) {
 			editpid = -1;
 			break;
 		} else {
 			unlink(tempname);
-			*tempname = '\0';
 			editpid = -1;
-			return (-1);
+			break;
 		}
 	}
+	sigaction(SIGINT, &sa_int, NULL);
+	sigaction(SIGQUIT,  &sa_quit, NULL);
+	sigprocmask(SIG_SETMASK, &oldsigset, NULL);
 	if (stat(tempname, &st2) == -1)
 		return (-1);
 	return (st1.st_mtime != st2.st_mtime);