From fcusack@ratbert.iconnet.net  Mon Dec 28 13:16:25 1998
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Message-Id: <199812281817.NAA25987@ratbert.iconnet.net>
Date: Mon, 28 Dec 1998 13:17:43 -0500 (EST)
From: fcusack@iconnet.net
Reply-To: fcusack@iconnet.net
To: krb5-bugs@MIT.EDU
Cc: fcusack@iconnet.net
Subject: prompter_posix() does not reset terminal on interrupt
X-Send-Pr-Version: 3.99

>Number:         680
>Category:       krb5-libs
>Synopsis:       krb5_prompter_posix does not restore terms setting on interrupt
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    krb5-unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   unknown
>Arrival-Date:   Mon Dec 28 13:17:00 EST 1998
>Last-Modified:
>Originator:     Frank Cusack
>Organization:
Icon CMT Corp.
>Release:        krb5-current-19981119
>Environment:
Unix
System: SunOS ratbert 5.6 Generic_105181-09 sun4u sparc SUNW,Ultra-5_10
Architecture: sun4

>Description:
	Signal handler used in krb5_prompter_posix() does not restore
	terminal echo settings. This will leave the terminal in a
	"non-echo" state if user sends an interrupt while the
	library is reading a hidden password.
>How-To-Repeat:
	Run kinit (using the new creds API) and type ^C when asked
	for the password.
>Fix:
fd and save_control are declared volatile b/c of setjmp()/longjmp()
semantics.

Index: prompter.c
===================================================================
RCS file: /icon/d04/cvsroot/3rd-party/krb5-19981119/lib/krb5/os/prompter.c,v
retrieving revision 1.3
diff -u -r1.3 prompter.c
--- prompter.c	1998/12/28 17:44:50	1.3
+++ prompter.c	1998/12/28 18:10:57
@@ -38,8 +38,9 @@
     krb5_error_code errcode;
     int i;
 #ifndef ECHO_PASSWORD
-    struct termios echo_control, save_control;
-    int fd;
+    struct termios echo_control;
+    volatile struct termios save_control;
+    volatile int fd;
 #endif
 
     if (name) {
@@ -52,8 +53,23 @@
        fputs("\n", stdout);
     }
 
+#ifndef ECHO_PASSWORD
+    fd = fileno(stdin);
+
+    if (isatty(fd) == 1) {
+	if (tcgetattr(fd, &echo_control) == -1)
+	    return errno;
+
+	save_control = echo_control;
+	echo_control.c_lflag &= ~(ECHO|ECHONL);
+    }
+#endif /* ECHO_PASSWORD */
+
     if (setjmp(pwd_jump)) {
 	errcode = KRB5_LIBOS_PWDINTR; 	/* we were interrupted... */
+#ifndef ECHO_PASSWORD
+	(void) tcsetattr(fd, TCSANOW, &save_control);
+#endif /* ECHO_PASSWORD */
 	goto cleanup;
     }
     /* save intrfunc */
@@ -62,16 +78,7 @@
     for (i=0; i<num_prompts; i++) {
 #ifndef ECHO_PASSWORD
 	if (prompts[i].hidden) {
-	    /* get the file descriptor associated with stdin */
-	    fd = fileno(stdin);
-
 	    if (isatty(fd) == 1) {
-		if (tcgetattr(fd, &echo_control) == -1)
-		    return errno;
-
-		save_control = echo_control;
-		echo_control.c_lflag &= ~(ECHO|ECHONL);
-
 		if (tcsetattr(fd, TCSANOW, &echo_control) == -1)
 		    return errno;
 	    }
@@ -110,7 +117,7 @@
 	    if ((tcsetattr(fd, TCSANOW, &save_control) == -1) &&
 		(errcode == 0))
 	        return errno;
-#endif
+#endif /* ECHO_PASSWORD */
     }
 
     errcode = 0;
>Audit-Trail:
>Unformatted: