bluhm discovered "script < /dev/null" attempts tty operations in violation

of pledge.  We can wrap isatty() around those codepaths.
ok bluhm beck

diff --git a/usr.bin/script/script.c b/usr.bin/script/script.c
index 57359ed..9dea1f1 100644 (file)
--- a/usr.bin/script/script.c
+++ b/usr.bin/script/script.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: script.c,v 1.32 2015/10/20 14:55:21 semarie Exp $     */
+/*     $OpenBSD: script.c,v 1.33 2017/04/12 14:49:05 deraadt Exp $     */
 /*     $NetBSD: script.c,v 1.3 1994/12/21 08:55:43 jtc Exp $   */
 
 /*
@@ -85,6 +85,7 @@ volatile sig_atomic_t sigdeadstatus;
 volatile sig_atomic_t flush;
 
 struct termios tt;
+int            istty;
 
 __dead void done(int);
 void dooutput(void);
@@ -99,7 +100,6 @@ main(int argc, char *argv[])
 {
        extern char *__progname;
        struct sigaction sa;
-       struct termios rtt;
        struct winsize win;
        char ibuf[BUFSIZ];
        ssize_t cc, off;
@@ -126,16 +126,22 @@ main(int argc, char *argv[])
        if ((fscript = fopen(fname, aflg ? "a" : "w")) == NULL)
                err(1, "%s", fname);
 
-       (void)tcgetattr(STDIN_FILENO, &tt);
-       (void)ioctl(STDIN_FILENO, TIOCGWINSZ, &win);
+       if (isatty(0)) {
+               if (tcgetattr(STDIN_FILENO, &tt) == 0 &&
+                   ioctl(STDIN_FILENO, TIOCGWINSZ, &win) == 0)
+                       istty = 1;
+       }
        if (openpty(&master, &slave, NULL, &tt, &win) == -1)
                err(1, "openpty");
 
        (void)printf("Script started, output file is %s\n", fname);
-       rtt = tt;
-       cfmakeraw(&rtt);
-       rtt.c_lflag &= ~ECHO;
-       (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &rtt);
+       if (istty) {
+               struct termios rtt = tt;
+
+               cfmakeraw(&rtt);
+               rtt.c_lflag &= ~ECHO;
+               (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &rtt);
+       }
 
        bzero(&sa, sizeof sa);
        sigemptyset(&sa.sa_mask);
@@ -331,7 +337,8 @@ done(int eval)
                (void)fclose(fscript);
                (void)close(master);
        } else {
-               (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &tt);
+               if (istty)
+                       (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &tt);
                (void)printf("Script done, output file is %s\n", fname);
        }
        exit(eval);